taxonID	type	description	language	source
038F19445869FFAE829D1CFFFA51F887.taxon	diagnosis	Diagnosis. Body length 5 – 16 mm, with slightly inflated pereon, especially in females. Head of females rounded, relatively large; slightly smaller in males but also rounded (Lycaea) or slightly pointed (Simorhynchotus); as long as first 3 – 5 pereonites. Eyes large, occupying most of head surface. A 1 of females with 2 - articulate peduncle, and enlarged first flagellar article (callynophore), followed by two small, terminal articles. A 1 of males with 2 - articulate peduncle, and enlarged, curved first flagellar article (callynophore) with two-field brush of aesthetascs medially, and three smaller, slender articles inserted on, or near, antero-distal corner. A 2 absent in females. A 2 of males with relatively short, slightly enlarged basal article, three slender articles folded back on one another and one short terminal article, tucked underneath head and pereon, between the pereopods. Mandibles with 3 - articulated palp in males, absent in females. Maxillae 1 very reduced in size, consisting of tiny rounded lobes, or absent. Maxillae 2 absent. Coxae 1 – 6 not fused with pereonites, although suture with pereonites very faint or difficult to discern. Coxa of P 7 seems to be fused with the pereonite. G 1 and G 2 simple, weakly chelate or sub-chelate. P 5 the longest. P 5 and P 6 often with moderately enlarged basis, distinctly shorter than remaining articles combined, which are inserted terminally. P 7 reduced in size, with full complement of articles, basis enlarged, longer than remaining articles combined. U 1 usually with articulated rami; endopod rarely fused with peduncle. U 2 endopod sometimes fused with peduncle. U 3 endopod always fused with peduncle. Telson triangular, apex rounded, usually extending to about limit of U 3, fused with double urosomite. Gills with folds on pereonites 2 – 6. Oostegites on pereonites 2 – 5.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445869FFAE829D1CFFFA51F887.taxon	discussion	Genera. Lycaea Dana, 1852 and Simorhynchotus Stebbing, 1888. Remarks. The systematic limits of this family are in a state of flux, with some authors including such diverse genera as Pseudolycaea (= Lycaea), Tryphana, Brachyscelus and Thamneus, besides Lycaea (e. g., Bowman & Gruner 1973, Shih & Chen 1995). Authors who have accepted this arrangement usually place Simorhynchotus in the family Oxycephalidae, based on the erroneous assumption that the maxillae are present in Lycaeidae and absent in Oxycephalidae and Simorhynchotus. While the maxillae are not discernible in Simorhynchotus, this is also only true for two genera of Oxycephalidae: Oxycephalus and Rhabdosoma. In all other genera of Oxycephalidae, the first maxillae are reduced to a small rounded lobe, and the second maxillae are absent, or so reduced that they cannot be distinguished from the buccal mass, as found in Brachyscelus and Lycaea. Thus, there is no valid reason to include Simorhynchotus in the family Oxycephalidae based on the absence of maxillae. The same applies to Metalycaea, a junior synonym of Lycaea, which Nair (1993) resurrected as a valid genus of Oxycephalidae based on the absence of maxillae. In Thamneus the maxillae are present as small rounded lobes and in Tryphana the maxillae are relatively well developed (Zeidler 2016). Thus, following the review of Zeidler (2016), the family Lycaeidae is restricted to the genera Lycaea and Simorhynchotus. Simorhynchotus more closely resembles Lycaea, rather than any genus of Oxycephalidae, in the general habit and the morphology of A 2 of males, and the gnathopods, pereopods, urosome and coxae. Also, in both Lycaea and Simorhynchotus, the A 2 of males extend posteriorly for almost the entire length of the pereon. In Oxycephalidae the A 2 of males usually extend posteriorly to about pereonite 2, and only in Tullbergella do they extend beyond pereonite 2, to about pereonite 5. Similarly, in other families of Platysceloidea the A 2 of males do not extend posteriorly much further than about pereonite 2, except for some genera of Platyscelidae and Parascelidae where they can extend to pereonite 3 or 4. Clearly the family Lycaeidae is most closely related to Oxycephalidae. Browne et al. (2007) and Hurt et al. (2013), utilising molecular techniques, also found strong support for the inclusion of Lycaea within the Oxycephalidae. One of the unusual characters of this family is that the coxae are very difficult to discern in preserved specimens. Upon initial observation they seem to be fused with the pereonites or a very faint suture is present. In order to resolve this problem a specimen of L. bovallii was carefully dissected and cleared so that the pereopods remained attached to the pereonites. As a result, I was able to determine that, at least for this species, the coxae of G 1 and G 2 have a very faint suture, those of P 3 and P 4 a faint suture, and those of P 5 and P 6 a slightly more defined suture with the pereonites, while the coxa of P 7 is fused with the pereonite and has a small posterior notch where a suture might have been. And this seems to be the condition of the coxae in all other species of Lycaea and Simorhynchotus.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445869FFAE829D1CFFFA51F887.taxon	description	Key to the genera of the family LYCAEIDAE Claus, 1879	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944586FFFAA829D1AAEFA51F8FC.taxon	type_taxon	Type species. Lycaea ochracea Dana, 1853 by subsequent designation. Type material could not be found in any major North American museum and is considered lost (see Evans 1967). The type locality is the S. W. Pacific, north of New Zealand, near Sunday Island, April 1840. Although the description and figures of Dana (1853) readily characterise this genus they have been considered insufficient to determine the status of his species. Dana (1853) illustrated a male, probably immature, judging by his figure of A 2. His figures characterise a species where the peduncle of U 1 is relatively long and the callynophore of A 2 of males has a postero-distal bulge. These two characters, combined with the morphology of G 2, exclude it from all its congeners except L. vincentii and L. bovallii. Dana’s small illustrations, however, make it difficult to determine the length of the dactyls and the exact position of the bulge on A 2. If anything, the dactyls seem short and the antennal bulge is near the distal margin. Thus, it is more like L. vincentii than L. bovallii. However, nomenclatural stability would not be served by re-introducing Dana’s name because his species has not been recorded since first described and the true identity of his species cannot be confirmed. Type species of synonyms. The type species of Pseudolycaea is P. pachypoda Claus, 1879 by monotypy. Type material could not be found in any major European institution and is considered lost. However, the description and figures of Claus (1879, 1887) readily characterise this species, which is considered to be insufficiently different from other species of Lycaea to warrant generic recognition (see Remarks). The type species of Metalycaea is M. globosa Stephensen, 1925 by monotypy. Three female syntypes are in the NHMD (84411, 86799, 86800). This species is considered to be a synonym of Lycaea serrata Claus, 1879 (see Remarks).	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944586FFFAA829D1AAEFA51F8FC.taxon	diagnosis	Diagnosis. Body robust or globular. Head round, often enlarged in females. Eyes occupying most of head surface; grouped in one field on each side of head. A 1 of males with 2 - articulate peduncle; flagellum with large, crescent-shaped callynophore, with aesthetascs arranged in two-field brush medially, with or without antero-distal corner and small, rounded postero-distal lobe; with three smaller articles inserted on antero-dorsal corner. A 1 of females with 2 - articulate peduncle; callynophore narrowly rectangular, with two smaller articles inserted terminally. A 2 absent in females. A 2 of males 5 - articulate, strongly zig-zagged, with most articles folded back on each other, extending anteriorly under head and posteriorly between the gnathopods and pereopods to pereonite 7; basal article distinctly inflated, about one-third the length of following article; following three articles of similar length; terminal article very short, not folded, pointing posteriorly. Mandibular incisor relatively broad, with several teeth, with small distal lobe medially; in males orientated more or less parallel to palp. Maxillae 1 consisting of tiny, rounded, plate-like lobes. Maxillae 2 absent. Maxilliped with inner lobes completely fused; medial margin of outer lobes with membranous fringe. G 1 and G 2 varying from almost simple to sub-chelate. P 3 and P 4 shorter than P 5 and P 6. P 5 basis usually enlarged, length about 1.5 – 2.0 x maximum width, or relatively narrow and about 3.0 x as long as wide (L. serrata); articles 3 – 7 inserted terminally on basis. P 6 basis also usually enlarged, length about 1.5 – 2.0 x maximum width; articles 3 – 7 inserted terminally on basis; dactylus retractile in some species. P 7 reduced in size with large basis; all articles present; dactylus prehensile, rarely absent or vestigial. U 1 endopod rarely fused with peduncle, sub-equal in length to exopod. U 2 endopod sometimes fused with peduncle, exopod always shorter and more slender than endopod. U 3 endopod fused with peduncle, exopod always shorter and more slender than endopod. Rami of U 1 – 3 lanceolate, usually with serrated margins. Species. Lycaea pulex Marion, 1874; L. nasuta Claus, 1879; L. serrata Claus, 1879; L. pachypoda (Claus, 1879); L. vincentii Stebbing, 1888; L. bovallii Chevreux, 1900; L. lilia Volkov, 1982; L. intermedia sp. nov.; L. osbornae sp. nov. and L. proserrata sp. nov. Sexual dimorphism. Apart from the morphology of the mandibles and the antennae, females are more robust than males, especially in the pereon. Males are generally more elongate and have a relatively smaller head, and in males of L. nasuta the head is more bulbous and produced into a small anterior knob; a character that also occurs in mature males of L. lilia, L. osbornae sp. nov. and L. proserrata sp. nov. But see diagnosis of L. serrata for exceptional sexual dimorphism.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944586FFFAA829D1AAEFA51F8FC.taxon	discussion	Remarks. In the past the genus Pseudolycaea has been considered monotypic amongst the family Lycaeidae, because of the almost simple G 1 and G 2. In all other respects it resembles Lycaea. As the morphology of G 1 and G 2 of Lycaea can vary from strongly to weakly sub-chelate, as in L. serrata, the validity of Pseudolycaea seems unjustified, and, like Vinogradov et al. (1982, 1996), it is here regarded a synonym of Lycaea. Similarly, Metalycaea, which Nair (1993) resurrected as a valid genus of Oxycephalidae, is considered to be a synonym of Lycaea, because the type species, M. globosa, originally described only from female specimens, is indistinguishable from mature female specimens of L. serrata. Like Simorhynchotus, its inclusion in the Oxycephalidae on the presumed absence of the maxillae has been demonstrated to be invalid (Zeidler 2016). An examination of the type material of M. globosa has confirmed the synonymy, although it was not possible to examine the mouthparts for the presence or absence of maxillae. The specimens referred to by Nair (1993) have not been examined. Species of Lycaea have always been difficult to determine and a thorough revision of the genus is long overdue. Harbison & Madin (1976) provide a useful key to eight species, that they tentatively consider valid. Of these eight species, Vinogradov et al. (1982, 1996) recognise only three, but they regard L. pauli considered synonymous with L. pulex by Harbison & Madin (1976) as valid, and include L. pachypoda and L. lilia. Clearly the genus still presents many taxonomic difficulties that require resolution. In order to clarify the systematics of the group, it is necessary to review some of the morphological characters that have been used to distinguish species in the past. Uropod 1. The peduncle length can vary considerably but most species can be placed into two groups based on the ratio of the length of the peduncle to the length of the exopod. The first group, with a relatively short peduncle and relatively long rami, where this ratio is about 2 x, consists of L. pulex, L. pauli, L. serrata, L. pachypoda and L. osbornae sp. nov. In addition, the peduncle is widest distally. The latter three species are readily distinguished by additional distinctive characters but this character, together with possessing short dactyls, also distinguishes Lycaea pulex from its other congeners. Lycaea pauli is considered a synonym of L. pulex. The second group, with a relatively long peduncle and relatively short rami, where this ratio is about 3 x or more, consists of the remaining species, except for L. lilia, which seems to be intermediate. In addition, the peduncle usually has evenly convex margins and is widest medially. Amongst this group this character is not sufficiently variable to be useful to distinguish species. Uropod 2. Two species, L. nasuta and L. bovallii, have been recorded as having the endopod fused with the peduncle. This character has been used to distinguish these two species from all other congeners (e. g., Harbison & Madin 1976). While L. nasuta is also readily distinguished by a number of other characters (see remarks for L. nasuta), L. bovallii is identical to L. bovallioides except for the urosome (Stephensen 1925, Harbison & Madin 1976) and the same seems applicable for L. bajensis. An examination of more than 80 specimens with medium length dactyls, referable to L. bajensis, and more than 40 specimens with longer dactyls, referable to L. bovallii or L. bovallioides, revealed that in only a few specimens is the endopod of U 2 clearly fused with the peduncle. In many specimens there seems to be a faint, or incomplete, suture between the endopod and the peduncle, depending on the angle of illumination under the microscope. Sometimes a faint suture is more evident on one side than the other in the same specimen. In all of the type material of L. bajensis available in the USNM, this suture is also faint. Thus, this character is unreliable and, in the absence of other distinguishing characters, L. bovallioides Stephensen, 1925 and L. bajensis Shoemaker, 1925 should be considered junior synonyms of L. bovallii Chevreux, 1900. Lycaea intermedia sp. nov. also has the endopod of U 2 fused with the peduncle and is morphologically very similar to L. bovallii but is readily distinguished by the shorter dactyls and other minor characters, as defined in the key and diagnosis of species provided further in this contribution. Gnathopods. The morphology of G 1 and G 2 varies from almost simple to strongly sub-chelate. In most species the carpus is expanded distally, ending in a sharp, tooth-like postero-distal corner, often protruding just beyond the distal margin of the propodus. In L. pachypoda G 1 and G 2 are almost simple with the postero-distal corner of the carpus reduced and rounded, barely extending posteriorly (Fig. 12). In L. lilia the postero-distal corner of the carpus is rounded and in L. nasuta and L. osbornae sp. nov. the corner is less sharp than in other species. In L. serrata the distal margin of the carpus is obliquely excavate, forming an imperfect sub-chela with the propodus but the postero-distal corner usually ends in a sharp, tooth-like point. Regarding the postero-distal corner of the propodus, the species can be divided into three groups; those without, where the margins of the propodus taper gradually to the base of the dactylus (L. serrata and L. proserrata sp. nov.); those with a small rounded corner (L. lilia, L. nasuta and L. osbornae sp. nov.), and the remaining species in which the postero-distal corner of the propodus is prominent, often serrated and ending in a rounded or sharp point. These characters, in combination with others as detailed in the key, are most useful to distinguish species. Pereopod 5. Some species, such as L. vincentii and L. bajensis, have been recorded with minor serrations on the anterior margin of the propodus of P 5. Harbison (1976) and Harbison & Madin (1976) use this character, amongst others, to distinguish some species. However, apart from L. vincentii, L. serrata and L. proserrata sp. nov. I have been unable to determine, with certainty, the presence or absence of such serrations in any other species, including the types of L. bajensis in the USNM. Mostly P 5 appears smooth under high magnification using a dissecting microscope and, even with a compound microscope, only very minor serrations can be observed / determined, especially for some specimens of L. vincentii. This character is used by Harbison & Madin (1976) to distinguish L. bajensis from L. bovallii and L. bovallioides, adding that L. bovallioides “ differs from L. bajensis only in the absence of serrations on the inner margin of the propodus of P 3, 4 and 5 ”. However, they did not have any specimens that they could identify with L. bajensis or L. bovallioides and relied on the descriptions of Shoemaker (1925) and Stephensen (1925) to make their determinations. So, like the above, this character seems to be unreliable providing further support for the synonymy of L. bajensis and L. bovallioides with L. bovallii. Male first antennae. There are three variations of the occurrence of a bulge on the anterior margin of the callynophore. In those without a bulge, the anterior margin tapers gradually to the insertion of the distal flagellar articles, without forming a prominent antero-distal corner (Fig. 5). Most species of Lycaea, except L. bovallii (and junior synonyms) and L. vincentii, belong to this group. All of these species are distinguished by several additional characters as detailed under those species and in the key. There are two variations of a bulge that occurs on the anterior margin. In only one species, L. vincentii, the bulge occurs medially, and the anterior margin slopes distally to the insertion of the remaining flagellar articles without forming a prominent antero-distal corner (Fig. 21). This character alone distinguishes L. vincentii from its congeners but it is only useful for males. In the remaining nominal species, a bulge occurs on the antero-distal corner forming a right angle with the distal margin (Fig. 3). The anterodistal corner can be raised in some specimens, forming a slight “ horn ”. This group consists of the nominal species L. bovallii, L. bovallioides, L. gracilis and L. bajensis, tentatively accepted by Harbison & Madin (1976). But slight variations of this character alone are not useful to distinguish these species and, in the absence of other distinguishing characters, the latter three species should be considered synonyms of L. bovallii. Pereopod dactylus length. Harbison & Madin (1976) consider the length of the dactylus of P 3 – 6 a good diagnostic character, especially of P 3 and P 4, and define three main types based on the length of the dactylus of P 4 relative to the propodus. Those with a short dactylus are about 0.2 x; those with a moderate dactylus 0.2 – 0.4 x; and those with a long dactylus are greater than 0.4 x, the length of the propodus. Using this system, the nominal species of Lycaea, accepted by Harbison & Madin (1976) fall into three groups: Lycaea nasuta, L. pulex, L. pachypoda and L. serrata with a short, almost stubby dactylus (L. lilia and L. pachypoda are also in this group); Lycaea vincentii with a moderate length dactylus; and L. bovallii (and its synonyms, L. bovallioides, L. bajensis and L. gracilis) with a long dactylus. The first group consists of species that are readily distinguished from each other by a number of other characters as defined in the following key and diagnosis of species. Amongst the latter group, L. gracilis Spandl, 1924 is considered a synonym of L. bovallii. It has not been recorded since its original description and Spandl’s (1924) illustrations of this and other species of hyperiideans (1924, 1927) are not always very accurate. The only character distinguishing L. gracilis from L. bovallii is the, apparently, rounded postero-distal corner of the propodus of G 2. For the remaining three species with “ a long dactylus ”, the dactylus length seems to vary slightly from about 0.5 x to almost 0.7 x the length of the propodus. Those with a very long dactylus are otherwise indistinguishable from those with a slightly shorter dactylus, and often the tip of the dactylus seems very slender and fragile and may be prone to breaking off. Thus, the remaining three species of the “ long dactylus ” group cannot be distinguished on the basis of the dactylus length alone and, in the absence of other defining characters, should be considered synonymous. The last remaining species, L. vincentii, with a moderate length dactylus, is also distinguished from the long dactylus group by the structure of the callynophore of the first antennae of males and by the minor serrations on the anterior margin of the propodus of P 5, as detailed above. Apart from these three characters, and that the endopod of U 2 is always articulated with the peduncle, it is like L. bovallii. The three species described as new here all have P 4 with a relatively short dactylus. In consideration of the above we are left with ten species of Lycaea considered valid in this review, including three described as new. Lycaea is a well-known associate of salps (Dana 1853, Marion 1874, Chevreux 1900, Harbison 1976, Harbison & Madin 1976, Madin & Harbison 1977). Harbison (1976) records the distribution of males, females and juveniles of L. pulex and L. vincentii on salp chains, and Madin & Harbison (1977) provide more information on the parasitic behaviour of Lycaea on salp hosts and the distribution of species. From the available evidence, it seems that females may remain on the host, once settled, while males are more pelagic in habit, seeking out the settled females. The greater development of the pleon and urosome of the male supports this hypothesis. Also, the few light-trap samples that are available in museum collections consist almost exclusively of males, or usually in greater numbers than found in general plankton samples, suggesting that they are active swimmers attracted to the light. Lycaea appears to be wide-spread in tropical and temperate regions of the world’s oceans. Because of the confused taxonomy of species, it is difficult to determine specific depth ranges, and these are often not recorded, but most seem to be epipelagic in habit.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944586FFFAA829D1AAEFA51F8FC.taxon	description	Key to the species of the genus Lycaea Dana, 1852	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445863FFA0829D1AAEFDA2FBA7.taxon	description	(Figs 1 – 3)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445863FFA0829D1AAEFDA2FBA7.taxon	materials_examined	Type material. Type material of Lycaea bovallii is in the Musée Océanographiqe de Monaco, Monaco (MOM). A holotype was not designated but a male from Hirondelle stn. 16 is illustrated by Chevreux (1900). Specimens were collected by the L’Hirondelle from the N. E. Atlantic, near the Azores [38 ° 06 ’ N 29 ° 18 ’ W], stn. 16, surface, 3 August 1885 (MOM 37 0019, 2 females, 3 males, in alcohol) and the N. E. Atlantic [48 ° 19 ’ N 19 ° 30 ’ W], stn. 30, surface, 27 August 1885 (MOM 37 0025, one juvenile, in alcohol) and [42 ° 50 ’ 26 ” N 45 ° 25 ’ W], stn. 148, surface, 28 July 1887 (MOM 37 0025, one juvenile, in alcohol). Type material of synonyms. The type material of Lycaea bajensis is in the USNM: the holotype male (USNM 52361) and 8 paratypes, 1 female, 7 males (USNM 52462). The type locality is the N. E. Pacific, Gulf of California. The holotype male (7 mm) and 8 paratypes are from off San Josef Island (“ Isla San José ”). Shoemaker also lists additional material from this locality and from off Cape San Lucas (5) and from off Carmen Island (3) but most of these specimens could not be found in the USNM. However, there are two lots amongst the general collection, one male from Carmen Island (USNM 52463) and three poorly preserved specimens from Cape San Lucas (USNM 52464) that should be considered paratype material. Unfortunately, the latter lot has only one specimen, a male that could be referred to L. bajensis; the remaining two specimens are females that are more readily identified with L. pulex and L. vincentii. An examination of this material has confirmed the above synonymy. Several syntypes of Lycaea gracilis are in the Naturhistorisches Museum Wien, in alcohol (NHMW 20163). Several specimens were collected from the Red Sea; Pola stns. 22 – 25, 64, 82, 108, 118, 136, and a male is illustrated by Spandl (1924). The long dactylus of P 4, the relatively long peduncle of U 1, the morphology of G 1 and G 2, and of the male A 1 are all characteristic of L. bovallii. Several syntypes of Lycaea bovallioides (4 – 5 mm) are in the NHMD, all labelled “ Type ”, in alcohol. Specimens were collected by the Thor from surface waters in the Mediterranean Sea, stn. 163 [37 ° 52 ’ N 26 ° 22 ’ E], 3 August 1910 (1 female, NHMD- 83719, previously CRU- 5875) and stn. 718 [36 ° 13 ’ N 13 ° 53 ’ E], 17 May 1913 (1 female, NHMD- 86792, previously CRU- 9293), and from the N. E. Atlantic, near Madeira, stn. 398 [36 ° 48 ’ N 14 ° 22 ’ W], 26 October 1911 (1 female, 1 male, NHMD- 86789, previously CRU- 9290); stn. 399 [34 ° 23 ’ N 15 ° 31 ’ W], 26 October 1911 (3 females, 3 males, NHMD- 86790, previously CRU- 9291) and stn. 400 [32 ° 10 ’ N 17 ° 20 ’ W], 30 October 1911 (12 males, NHMD- 86791, previously CRU- 9292). The figured male is from stn. 400 (Stephensen 1925) and is here designated the lectotype, the remaining syntypes become paralectotypes. An examination of this material has confirmed the above synonymy. Material examined. Type material of Lycaea bajensis and L. bovallioides as detailed above and the following. In NHMD: N. Atlantic, 9 females, 5 males (6 lots), Dana stns 1142 vii, 1145 vii (228137 – 8), 1231 v (228141), 4000 v (228231), and Thor stns 385, 399. S. W. Atlantic, 3 females, 1 male, Dana stn. 3997 v (228228). Indian Ocean, from Sumatra to South Africa, 18 females, 7 males (17 lots, all Dana), stns 3821 v, 3843 i, 3844 iii-iv, 3851 ii-iv (228175 – 9, 228181, 619434), 3854 i (228183), 3918 v (228189), 3920 viii, 3921 ii, 3921 vii (228193 – 5), 3928 iii (228203), 3931 iii (619436), 3937 ii (228216), 3959 iv (228223), 3843 iv (228255). Tropical Pacific, 20 females, 16 males (20 lots, all Dana), stns 3548 v, 3553 i (228143 – 4); 3561 x (228146); 3563 ii, 3569 I, 3569 iv, (228148 – 50); 3579 v, 3584 ii (228152 – 3); 3584 vi, 3584 vii (228155 – 6); 3585 v (228158); 3587 ix (228161); 3588 ii, 3588 iii, 3602 v, 3611 iv 3611 vi, 3626 iv, 3663 ix – x (228163 – 70). Tasman Sea, 1 female, Dana stn. 3665 iv (619246). Mediterranean Sea, 19 females, 11 males (11 lots), Dana stns 4050 xxi-iii, 4050 v (228233 – 6), and Thor stns 10, 143, 144, 163, 182, 183, 297. In SAM and SAMA (part): Meiring Naude collections from S. W. Indian Ocean, off South Africa, between Kosi Bay and just south of East London, 97 females, 63 males (53 lots), mostly 200 – 0 m, few 528 – 0 m. In SAM: S. W. Atlantic, off South Africa, 19 females, 8 males (7 lots). In SAMA: N. E. Indian Ocean, off northern Western Australia, Ningaloo Reef and Dampier Archipelago region, 8 females, 19 males (9 lots), C 12558 – 66. Tasman Sea, north of Sydney, 1 female, 1 male (2 lots), C 5264 – 5. Japan, Ryukyu Islands, 2 females, 1 male (2 lots), C 12567 – 8. S. W. Atlantic, off Brazil [31 ° 05 ’ S 49 ° 50 ’ W], 2 males, C 12569. In USNM: N. W. Atlantic from French Guiana in the south, north to Georges Bank, off Massachusetts, 38 females, 17 males (28 lots), 106183, 181803, 1154670, 1154682, 1171017, 1178027, 1198726, 1241233, 1241235, 1241238, 1241240, 1241242, 1241245, 1241286, 1242779, 1242784 – 5, 1242787, 1242793, 1242807, 1242810 – 11, 1246891, 1246972 – 3, 1246977 – 8, 1247116, 1247126. S. W. Atlantic, off Brazil [08 ° S 30 ° W], 3 females, 2 males (2 lots), 1246990, 1247117. N. E. tropical Pacific, off Costa Rica and Nicaragua, 5 females, 20 males (3 lots), 1242773, 1242776, 1242778. N. W. Pacific, Japan, Philippines and China Sea region, 12 females, 26 males (10 lots), 1242774 – 5, 1242777, 1242796, 1242798 – 800, 1242803 – 4, 1246961. N. W. Indian Ocean, near Mauritius [19 ° 34 ’ N 62 ° 14 ’ 09 ” E], 1 female, 1246891.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445863FFA0829D1AAEFDA2FBA7.taxon	diagnosis	Diagnosis. Body length up to about 5.0 mm for females and 7.0 mm for males, but ovigerous females of about 3.0 mm have been noted. Head of females relatively large, much deeper than long (about 1.5 x), as long as first 5 pereonites combined, sometimes slightly shorter or longer. Head of males more rounded, slightly deeper than long (about 1.3 x), almost as long as first 5 pereonites combined. Buccal mass barely protruded below head. Callynophore of A 1 of males with acute antero-distal corner extending at right angles well above following article; postero-distal corner small, rounded, separated from following article by distinct notch. G 1 and G 2 sub-chelate, morphologically similar, G 2 slightly longer than G 1; basis of G 1 slightly broader and shorter than G 2; carpus rectangular with sharp postero-distal tooth, reaching just past base of dactylus; propodus with postero-distal corner produced posteriorly to dactylus; carpus and propodus with small serrations on distal and posterior margins; dactylus slender, length 0.5 – 0.6 (females), 0.6 – 0.8 (males) x propodus. P 3 – 6 with relatively long, slender dactylus, those of P 3 and P 4 at least 0.5 x as long as propodus or longer. P 3 and P 4 morphologically similar, P 4 slightly longer than P 3; merus marginally inflated anteriorly, slightly longer than propodus, about 0.6 x basis; carpus length about 0.6 – 0.7 x propodus. P 5 length about 1.2 x P 4 in females, 1.4 x P 4 in males and about 1.4 x P 6 in both sexes; basis rectangular, length about 2.4 x maximum width; merus marginally inflated anteriorly, slightly longer than propodus, about 0.6 – 0.7 x basis; carpus length about 0.7 x propodus. P 6 basis oval-shaped, length about 2 x maximum width, slightly shorter than basis of P 5; merus relatively narrow; merus, carpus and propodus similar in relative lengths to P 5; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin, wider in males with length about 1.5 x maximum width, in females length almost 2 x width, about 0.6 – 0.7 x basis of P 6; remaining articles together very short, less than 0.2 x basis; propodus with small, rounded, antero-distal corner; dactylus sharp, hook-like. U 1 peduncle relatively long, more than 3.0 x length of exopod; rami relatively slender, equal in length. U 2 endopod usually fused with peduncle. Telson length about equal to width at base in males, slightly longer in females.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445863FFA0829D1AAEFDA2FBA7.taxon	discussion	Remarks. The validity of Lycaea bovallii has been in doubt in the past and Vinogradov et al. (1982, 1996) consider it a synonym of L. pulex, along with L. bovallioides and L. bajensis. However, like Harbison & Madin (1976), it is here regarded a valid species, distinguished from L. pulex by the relatively longer peduncle of U 1, in that the endopod of U 2 is usually fused with the peduncle, and by the relatively longer dactylus of P 4 (and other pereopods). Males are further distinguished by the morphology of the callynophore of A 1 as detailed above. Lycaea gracilis, L. bovallioides, and L. bajensis, cannot be clearly distinguished from L. bovallii, as demonstrated above and are thus considered junior synonyms. However, this species is very similar to L. vincentii in the relatively long peduncle of U 1 and in the morphology of the callynophore of A 1 of males. Regarding the latter character, the main difference is in the position of the antero-distal bulge as detailed above. Apart from the relatively longer dactylus of P 4 (and other pereopods), it is most readily distinguished from L. vincentii by the fused endopod of U 2, although this is not always easy to determine. Also, the buccal mass is not protruded as much below the head and the remaining articles of P 7, distal to the basis, are together relatively short, less than 0.2 x the basis length compared to 0.3 x, or more, for L. vincentii, although this character may be variable. In view of the above synonymy, especially that of L. bajensis, Lycaea bovallii has become one of the more common species of Lycaea in the N. W. Atlantic Ocean. Lycaea bovallii has been recorded with the following salps (as L. bovallioides), Cyclosalpa pinnata (Forsskål, 1775), Pegea socia (Bosc, 1802), P. confoederata (Forsskål, 1775), Iasis cylindrica (Cuvier, 1804) and S. maxima Forsskål, 1775 (Madin & Harbison 1977). It has also been recorded with the pteropod Corolla spectabilis Dall, 1871 (Harbison et al. 1977).	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445863FFA0829D1AAEFDA2FBA7.taxon	distribution	Distribution. Determining the distribution of this species is problematical, mainly because of its past confusion with L. pulex. Material in the USNM is mainly from the N. W. Atlantic Ocean, as might be expected. Considering the above synonymy, more reliable records are as follows. In the Atlantic Ocean: from about 40 ° N, throughout the tropical regions, and as far south as 31 ° S, off Brazil. In the Pacific Ocean: mainly from the tropics off Chile and Peru, the Gulf of California, the China Sea and near Japan, and the Tasman Sea, off eastern Australia. In the Indian Ocean: mainly from the tropical south-west and also the Red Sea. The SAMA also has several specimens collected from off the north-western coast of Western Australia. It has also been recorded from the Mediterranean Sea. Most of these records are from near the surface.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445866FFBC829D1E5AFD0EFD7B.taxon	description	(Figs 4 – 5)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445866FFBC829D1E5AFD0EFD7B.taxon	materials_examined	Material examined. Holotype. Female, 5.7 mm (ovig.), NHMD- 228206, Dana stn. 3931 iii, S. W. Indian Ocean, N. of Madagascar [12 ° 09 ’ S 49 ° 34 ’ E], 300 mw, 19 December 1929. Allotype. Male, 6.3 mm, NHMD- 228225, Dana stn. 3964 v, S. W. Indian Ocean, S. W. of Madagascar [25 ° 19 ’ S 36 ° 13 ’ E], 50 mw, 15 January 1930. Paratypes. All from the following Dana stations. Central South Pacific: 1 male, NHMD- 619243, 3561 x [04 ° 20 ’ S 116 ° 46 ’ W], 50 mw, 24 September 1928; 1 female, NHMD- 228151, 3579 iv [20 ° 56 ’ S 160 ° 03 ’ W], 100 mw, 23 October 1928; 2 females, NHMD- 228154, 3584 iii [10 ° 51.5 ’ S 168 ° 40 ’ W], 400 mw, 29 October 1928; 1 male, NHMD- 228159, 3585 xi [11 ° S 172 ° 37 ’ W], 300 mw, 2 November 1928; 1 female, NHMD- 228162, 3587 xiii [11 ° S 172 ° 37 ’ W], 50 mw, 2 November 1928; 1 female, NHMD- 228172, 3748 ii [03 ° 48 ’ S 133 ° 35 ’ E], 150 mw, 10 July 1929. Indian Ocean: E. of Sumatra to South Africa: 1 female, NHMD- 228173, 3815 vii [03 ° 36 ’ S 97 ° 37 ’ E], 500 mw, 10 September 1929; 2 females, NHMD- 228180, 3851 iii [05 ° 27 ’ S 93 ° 50 ’ E], 200 mw, 15 October 1929; 1 female, NHMD- 228182, 3851 iv [05 ° 27 ’ S 93 ° 50 ’ E], 100 mw, 15 October 1929; 1 female, NHMD- 228185, 3916 v [01 ° 45 ’ N 73 ° 03 ’ E], 50 mw, 4 December 1929; 1 female, NHMD- 228187, 3918 ii [00 ° 35 ’ N 66 ° 09 ’ E], 600 mw, 7 December 1929; 1 female, NHMD- 228190, 3919 iii [00 ° 07 ’ S 63 ° 56 ’ E], 300 mw, 8 December 1929; 1 male, NHMD- 228196, 3921 viii [03 ° 36 ’ S 58 ° 19 ’ E], 100 mw, 11 December 1929; 1 female, NHMD- 228200, 3926 i [08 ° 27 ’ S 50 ° 54 ’ E], 600 mw, 16 December 1929; 1 female, NHMD- 228205, 3930 v [11 ° 55 ’ S 49 ° 55 ’ E], 100 mw, 19 December 1929; 3 females, 1 male, NHMD- 619435, 3931 iii [12 ° 09 ’ S 49 ° 34 ’ E], 300 mw, 19 December 1929; 1 male, NHMD- 228208, 3931 iv [12 ° 09 ’ S 49 ° 34 ’ E], 200 mw, 19 December 1929; 3 females, 1 male, NHMD- 228209, 3932 ii [11 ° 35 ’ S 48 ° 45 ’ E], 300 mw, 20 December 1929; 1 female, NHMD- 228212, 3934 iv [11 ° 24 ’ S 52 ° 05 ’ E], 200 mw, 20 December 1929; 1 female, NHMD- 228213, 3934 v [11 ° 24 ’ S 50 ° 05 ’ E], 200 mw, 20 December 1929; 1 female, NHMD- 228214, 3935 ii [10 ° 50 ’ S 48 ° 30 ’ E], 400 mw, 21 December 1929; 1 male, NHMD- 228217, 3938 ii [09 ° 10 ’ S 45 ° 17 ’ E], 400 mw, 23 December 1929; 1 female, NHMD- 228220, 3951 iv [14 ° 16 ’ S 41 ° 48 ’ E], 50 mw, 7 January 1930; 1 male, NHMD- 228224, 3964 iii [25 ° 19 ’ S 36 ° 13 ’ E], 300 mw, 15 January 1930. S. E. Atlantic: 3 females, 2 males, NHMD- 228227, 3980 x [23 ° 26 ’ S 03 ° 56 ’ E], 50 mw, 17 February 1930. Tasman Sea: 1 male, NHMD- 228171, 3665 iv [29 ° 37 ’ S 156 ° 46 ’ E], 100 mw, 25 February 1929. Other material. Indian Ocean: All but last lot from the following Dana stations, mostly in poor condition. 1 female, NHMD- 228184, 3907 iii; 1 male, NHMD- 228186, 3917 vii; 1 female, 1 male, NHMD- 228188, 3918 iv; NHMD- 228192, 3919 v; 4 females, NHMD- 228197, 3924 iv; 1 male, NHMD- 228199, 3924 v; 1 female, NHMD- 228201, 3926 iii; 1 male, NHMD- 228202, 3927 iii; 1 female, NHMD- 228204, 3929 vii; 2 females, NHMD- 228210 – 11, 3932 iii, 3932 x; 2 females, NHMD- 228215, 3936 v; 2 females, NHMD- 228218, 3948 ii; 1 female, NHMD- 228219, 3949 iii; 1 male, NHMD- 228221, 3958 ii. N. E. Atlantic: 1 female, NHMD- 228139, 1145 ix, 1 male, NHMD- 228140, 1145 x. South China Sea: 1 male, NHMD- 228238, 4815. S. of Japan: 2 females, NHMD- 228237, Jutlandia stn. 4775.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445866FFBC829D1E5AFD0EFD7B.taxon	description	Description of holotype. Female, 5.7 mm (ovig.). Head relatively large, much deeper than long (about 1.6 x), almost as long as first 5 pereonites combined. Buccal mass protruded well below head. Pereonite 2 with slight dorsal hump. G 1 and G 2 sub-chelate, morphologically similar, G 2 slightly longer than G 1; basis of G 1 slightly broader and shorter than G 2; carpus rectangular with sharp postero-distal tooth, reaching just past base of dactylus; propodus with postero-distal corner produced posteriorly to dactylus; carpus and propodus without small serrations on distal and posterior margins; dactylus slender, length about 0.6 x propodus. P 3 – 6 with relatively short, stubby dactylus, those of P 3 and P 4 about 0.2 x length of propodus. P 3 and P 4 morphologically similar, P 4 slightly longer than P 3; merus marginally inflated anteriorly, slightly shorter than propodus, about 0.5 x basis; carpus length about 0.7 (P 3) or 0.8 (P 4) x propodus. P 5 length about 1.2 x P 4 and about 1.4 x P 6; basis oval-shaped, length about 2 x maximum width; merus sub-equal in length to propodus, about 0.6 – 0.7 x basis; carpus length about 0.7 x propodus. P 6 basis oval-shaped, length about 1.5 x maximum width, slightly shorter than basis of P 5; merus with slightly inflated anterior margin, sub-equal in length to propodus, about 0.5 x basis; carpus length about 0.6 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with slightly bulging posterior margin, length about 1.8 x maximum width, about 0.9 x basis of P 6; length of remaining articles together about 0.6 x basis; propodus with antero-distal corner produced into small, rounded lobe; dactylus sharp, hook-like. U 1 peduncle relatively long, slightly more than 3.3 x length of exopod; rami relatively slender, equal in length. U 2 endopod fused with peduncle. Telson slightly longer than width at base, with rounded tip. Description of allotype. Male 6.3 mm. Like holotype female except for the following. Head more rounded, marginally deeper than long, almost as long as first 5 pereonites combined. Buccal mass barely protruded below head. A 1 callynophore without antero-distal corner; postero-distal corner small, rounded, separated from following article by distinct notch. Pereonite 2 without dorsal hump. Dactylus of G 1 and G 2 slightly longer, almost 0.7 x propodus. P 5 length about 1.4 x P 4 and about 1.3 x P 6; basis rectangular; merus length about 0.8 x propodus. P 6 merus slightly shorter than propodus; dactylus retractile in small hollow at base of propodus. P 7 basis broader, length about 1.5 x maximum width; length of remaining articles together slightly more than 0.4 x basis. Variations. Ovigerous females of Lycaea intermedia ranged in size from 5.0 mm (NHMD- 228180) to 6.1 mm (NHMD- 228185). Males seem to be mature at about 6.0 mm but the largest male recorded was 9.2 mm (NHMD- 228227), but this was probably an exceptional example because the next largest specimen was only 7.3 mm (NHMD- 228159). Whether or not the dactylus of P 6 is retractile is difficult to determine unless it is at least partly retracted. In some specimens it is only partly retracted and sometimes only on one side. However, this character was recorded in several males apart from the allotype (NHMD- 228171; 228196, 228224, 228227) as well as in several females (NHMD- 228173, 228182, 228185, 228227).	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445866FFBC829D1E5AFD0EFD7B.taxon	etymology	Etymology. Lycaea intermedia shares some characters with both L. bovallii and L. nasuta but is distinguished from them by a combination of several characters as detailed below. Hence it is considered to be somewhat “ intermediate ” between the two.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445866FFBC829D1E5AFD0EFD7B.taxon	discussion	Remarks. Lycaea intermedia was extracted from a lot labelled “ L. nasuta ” amongst the collections of Dana material in the NHMD. It was probably identified as such based on the morphology of U 2 in that the inner ramus is fused with the peduncle. This would now also include L. bovallii. However, only three lots were identified as L. nasuta, the remainder were determined as L. bovallii or L. intermedia. Vinogradov et al. (1982, 1996) erroneously describe and illustrate G 1 and G 2 of L. nasuta as being similar to L. pulex and it is likely that this reference was used to determine the Dana material resulting in the mis-identification. Lycaea intermedia is most similar to L. bovallii in the general habitus of both sexes, the relatively long peduncle of U 1 and in that the inner ramus of U 2 is fused with the peduncle, but is readily distinguished from it by the shorter, stubby dactylus of P 3 – 6 and by the absence of serrations on the postero-distal corners of the carpus and propodus of G 1 and G 2. In addition, females of L. intermedia are distinguished by the small dorsal hump on the second pereonite, a character which is also shared with L. nasuta (also found in some specimens of L. lilia), and in males the callynophore of A 1 is without an antero-distal hump, a distinctive character of L. bovallii and L. vincentii. In addition to the above, it also resembles L. nasuta in that P 3 – 6 have a relatively short dactylus but differs in that the dactylus of G 1 and G 2 is relatively longer and the morphology of both is similar, whereas for L. nasuta the propodus of G 2 extends well beyond the postero-distal corner of the carpus, unlike G 1. In addition, the head of males is rounded, without the characteristic anterior knob found in L. nasuta. Another distinctive character of L. intermedia is the retractile dactylus of P 6, a character not found in any other species except L. osbornae sp. nov. (infra) but it is not evident in all specimens and can be difficult to determine unless the dactylus is at least partly retracted. A salp associate has not been recorded for this species.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445866FFBC829D1E5AFD0EFD7B.taxon	distribution	Distribution. The Dana collections, as detailed above, indicate that this species is widely distributed in the tropical regions of the Pacific and Indian Oceans, with a few records from the Atlantic Ocean and the Tasman Sea. It seems to be most common in the Indian Ocean.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587AFFB9829D1926FBD1FD47.taxon	description	(Figs 6 – 7)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587AFFB9829D1926FBD1FD47.taxon	materials_examined	Type material. The holotype female (9.0 mm) and some paratypes are held by the Pacific Ocean Scientific Research Institution of Fisheries and Oceanography (TINTRO). The type locality is the S. E. Pacific [08 ° S 90 ° W & 13 ° S 86 ° W], 0 – 100 m. Material examined. In NHMD: S. Pacific: near Samoa, Dana stns 3558 ii (228124), 3584 vi (228126), 3584 vii (228129), 3588 iii (228130), 3 females, 2 males. China Sea: N. of Luzon, Dana stn. 3729 iii (228131), 1 female. S. E. Indian Ocean: S. of Sumatra, Dana stn. 3856 iv (228133), 2 females. S. W. Indian Ocean: N. of Madagascar, Dana stn. 3931 (228135), 1 female. In USNM: N. E. Pacific: 2 females, 3 males (1242788), “ Colombia, Port Utria, Chaco ”, R / V Velero III, surface, 15 February 1934.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587AFFB9829D1926FBD1FD47.taxon	diagnosis	Diagnosis. Body length up to about 9.0 mm. Head of females relatively large, rounded, much deeper than long (about 1.5 x), as long as first 3 – 4 pereonites combined. Head of males almost as long as first 3 pereonites combined, usually with small, anterior knob. Buccal mass protruded well below head. Pereonite 2 of females sometimes with slight dorsal hump. Callynophore of A 1 of males without antero-distal corner; postero-distal corner small, rounded, separated from following article by small notch. G 1 and G 2 sub-chelate, G 2 slightly longer than G 1. G 1 basis slightly shorter than for G 2; carpus rectangular with small, rounded postero-distal tooth, reaching just past base of dactylus; propodus with small postero-distal corner produced very slightly over dactylus; carpus and propodus with smooth margins; dactylus very short, stubby, length less than 0.3 x propodus. G 2 carpus similar to G 1 but distal margin only extends to about the middle of the propodus; propodus of males with few small serrations distally on posterior margin, otherwise similar to G 1. P 3 – 6 with very short, stubby dactylus, those of P 3 and P 4 about 0.2 x as long as propodus, or slightly less. P 3 and P 4 morphologically similar, P 4 slightly longer than P 3; merus marginally inflated anteriorly, slightly shorter than propodus, about 0.4 – 0.5 x basis; carpus length about 0.7 x propodus. P 5 length about 1.4 x P 4 and about 1.3 x P 6 in both sexes; basis rectangular, length about 2 x maximum width; merus marginally inflated, slightly longer than propodus, about 0.6 x basis; carpus length about 0.7 x propodus. P 6 basis oval-shaped, slightly wider distally in males, length about 2 x maximum width, slightly shorter than basis of P 5; merus distinctly inflated, maximum width slightly more than 0.6 x length, sub-equal in length to propodus, about 0.5 x basis; carpus also slightly inflated, length almost 0.7 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin, wider in females, length about 1.5 x maximum width, in males length about 1.7 x maximum width, about 0.7 x basis of P 6; remaining articles together relatively long, almost 0.7 x basis in males and almost as long as basis in females; propodus with antero-distal corner produced into small, rounded lobe; dactylus sharp, hook-like. U 1 and U 2; endopod not fused with peduncle. U 1; peduncle relatively short, about 2.5 x length of exopod or only slightly longer; rami relatively slender, equal in length. Telson length about equal to width at base, relatively shorter and more rounded than for other species.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587AFFB9829D1926FBD1FD47.taxon	discussion	Remarks. Lycaea lilia is readily distinguished from all its congeners, except L. nasuta and L. osbornae sp. nov. by the morphology of G 2 in that the carpus is relatively narrow so that the propodus extends well beyond the postero-distal corner of the carpus. It also shares two other distinctive characters with L. nasuta: the morphology of the head of males is similar and, in some females, the second pereonite has a small dorsal hump. Clearly the two species are closely related but L. lilia is readily distinguished by the morphology of U 2 (peduncle and endopod not fused) and the morphology of G 1 and G 2 in that the postero-distal corner of the carpus is relatively rounded and does not end in a distinct tooth. It is distinguished from L. osbornae sp. nov. as detailed under that species. The male of Lycaea lilia has not been illustrated previously in the literature and is unusual in that the head is produced into a small, rounded knob, anteriorly, similar to males of L. nasuta. Unfortunately, of the four males at hand, two are immature and the other two are recent moults so it is impossible to adequately describe the antennae. A salp associate has not been recorded for this species.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587AFFB9829D1926FBD1FD47.taxon	distribution	Distribution. A relatively rare species known only from the tropical E. Pacific, the tropical S. E. and S. W. Indian Ocean and the China Sea as detailed above, and from off central Mexico (Gasca et al. 2010). It seems to prefer shallow waters with records from hauls of 100 – 0 m and with 50 – 600 mw.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587FFFBA829D197AFE43FC7F.taxon	description	(Figs 8 – 9)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587FFFBA829D197AFE43FC7F.taxon	materials_examined	Type material. Type material of Lycaea nasuta could not be found in any major European institution and is considered lost. The type locality is the W. Indian Ocean, off Zanzibar. Claus’s (1887) illustration of a male, although limited to the habitus, gnathopods and uropods, readily characterise this distinctive species. Material examined. In NHMD: tropical Atlantic, Dana stn. 3998 xi (228229), 1 male; Dana stn. 4000 iii (228230), 2 females. S. Pacific, Dana stn. 3561 iv (228145), 1 female. In USNM: N. W. Atlantic, from the Bahamas in the south, north to Georges Bank, off Massachusetts, 9 females, 5 males (6 lots), 10878, 1241181, 1241239, 12421289, 1246893., 1246974. S. W. Atlantic, off Brazil [01 ° 06 ’ S 35 ° 10 ’ W], 1 female, 1247115. N. Pacific, off Hawaii [19.42 ° N 156.07 ° W], 1 female, 1196356.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587FFFBA829D197AFE43FC7F.taxon	diagnosis	Diagnosis. Body length of mature females up to 8.0 mm and males up to 9.0 mm. Head of females relatively rounded, slightly deeper than long, as long as first 4 pereonites combined; the eyes more massive than in other species, wider than anterior pereonites in dorsal view. Head of males (when mature) with distinctive rounded knob anteriorly, relatively smaller than for females, slightly deeper than long, almost as long as first 4 pereonites combined. Buccal mass protruded only slightly below head. Callynophore of A 1 of males without antero-distal corner; postero-distal corner small, rounded, partly over-lapping following article. G 1 and G 2 sub-chelate, G 2 slightly longer than G 1. G 1 basis slightly shorter than that of G 2, inflated anteriorly with evenly rounded anterior margin; carpus rectangular with small, sharp, postero-distal tooth, reaching just past base of dactylus; propodus with small, rounded, postero-distal corner produced posteriorly to dactylus; dactylus relatively short, curved, length about 0.3 x propodus. G 2 basis relatively slender; carpus narrow, postero-distal tooth only reaching to about 0.6 x posterior margin of propodus; propodus and dactylus like that of G 1. P 3 – 6 with relatively short, stubby dactylus, those of P 3 and P 4 slightly less than 0.2 x propodus. P 3 and P 4 morphologically similar, P 4 slightly longer than P 3; merus slightly inflated anteriorly, sub-equal in length to carpus, about 0.8 x propodus and almost 0.5 x basis. P 5 relatively longer than for other species, about 1.5 x P 4 and P 6 (slightly less in males); basis rectangular, length slightly more than 2 x maximum width; merus length about 0.8 x propodus, almost 0.7 x basis; carpus length slightly less than 0.6 x propodus. P 6 basis rectangular, length about 2 x maximum width, slightly shorter than basis of P 5; merus slightly inflated anteriorly; merus, carpus and propodus similar in relative lengths to P 5; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin, length about 1.5 x maximum width, about 0.7 – 0.8 x basis of P 6; length of remaining articles about 0.5 x basis, or slightly more; propodus with antero-distal corner produced into rounded lobe; dactylus sharp, hook-like. U 1 peduncle relatively wider than for other species, length about 3.0 x exopod; endopod rarely fused with peduncle; rami relatively broad, equal in length. U 2 endopod fused with peduncle. Telson slightly longer than width at base, with evenly rounded apex.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587FFFBA829D197AFE43FC7F.taxon	discussion	Remarks. A combination of three characters distinguishes Lycaea nasuta from its congeners: i) the relatively short dactylus of P 3 and P 4; ii) the narrow carpus of G 2, which is shorter than the posterior margin of the propodus; and iii) the fusion of the inner ramus of U 2 with the peduncle. The morphology of G 2 is similar to L. lilia and L. osbornae sp. nov., but in the former the postero-distal corner of the carpus is rounded and in the latter the carpus is more rectangular and the dactylus is more slender and longer; also the morphology of G 1 and G 2 is similar. Lycaea nasuta also bears some similarity to L. intermedia, as discussed under that species. Lycaea nasuta has, to date, only been recorded with the salp Cyclosalpa affinis (Chamisso, 1819) (Madin & Harbison 1977).	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587FFFBA829D197AFE43FC7F.taxon	distribution	Distribution. Known only from a few records; from the Indian and Atlantic Oceans around South Africa, from the north and S. E. mid-Atlantic, and from the Pacific Ocean, in the south, near New Zealand to about 42 ° S, and in the north off the eastern coast of America, from California to Mexico and off Peru and Chile. Most catch records are from near the surface.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587CFFB5829D1E22FDC9F823.taxon	description	(Figs 10 – 11)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587CFFB5829D1E22FDC9F823.taxon	materials_examined	Material examined. Holotype: Female, 4.7 mm, USNM 1242790. North Atlantic, Georges Bank, S. of Massachusetts [39 ° 26 ’ N 68 ° 03 ’ 30 ” W], R / VAlbatross, surface, 31 August 1885. Allotype: Male, 5.2 mm (recently moulted), NHMD- 228125, Dana stn. 3563 iv, S. E. Pacific, N. E. of Marquesas Is. [07 ° 45.5 ’ S 131 ° 22 ’ W], 100 mw, 29 September 1928. Paratypes 1: 1 female, 3.7 mm, USNM 1242790, collected with holotype. 2: 1 female, 3.3 mm, SAMA C 12577, N. E. Pacific, off Vancouver Island [49 ° 15.09 ’ N 126 ° 40 ’ W], “ LaPerouse and Line P Monitoring Program ”, stn. A 4, 250 m, September 2009 (from M. Galbraith). On the salp Cyclosalpa bakeri Ritter, 1905. 3: 1 female 5.8 mm, NHMD- 619242, collected with allotype. 4: 1 female, 4.4 mm, NHMD- 228132, Dana stn. 3843 iv, S. E. Indian Ocean, N. of Cocos / Keeling Is. [09 ° 59 ’ S 97 ° 56 ’ E], 200 mw, 9 October 1929. 5: 2 females, 6.1 and 6.5 mm, NHMD- 228242, Dana stn. 1208 iii, N. E. Pacific, off Panama [06 ° 48 ’ N 80 ° 33 ’ W], 300 mw, 16 January 1922. 6: 2 males about 8.6 mm, NHMD- 228248, Dana stn. 3563 v, same data as allotype but 50 mw.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587CFFB5829D1E22FDC9F823.taxon	description	Description of holotype. Female, 4.7 mm. Head relatively large, rounded, much deeper than long (about 1.7 x), as long as first 3 pereonites combined. Buccal mass protruded well below head. G 1 and G 2 sub-chelate, G 1 slightly shorter than G 2. G 1 with slightly inflated basis; carpus rectangular with small, pointed, postero-distal tooth, reaching to about the middle of the propodus; propodus with small, slightly serrated, postero-distal corner produced very slightly posteriorly to dactylus; dactylus slender, relatively long, length 0.5 x propodus. G 2 similar to G 1 except for basis which is more slender and longer (1.5 x that of G 1) accounting for the extra length. P 3 – 6 with very short, stubby dactylus, those of P 3 and P 4 about 0.2 x as long as propodus, or slightly more. P 3 and P 4 morphologically similar, P 4 slightly longer than P 3; merus marginally inflated anteriorly, marginally longer than propodus, about 0.5 x basis; carpus marginally shorter than propodus. P 5 length about 1.2 x P 4 and P 6; basis rectangular, length about 2 x maximum width; merus marginally inflated anteriorly, sub-equal in length to propodus, about 0.6 x basis; carpus length about 0.8 x propodus. P 6 basis rectangular but slightly wider medially, length about 2 x maximum width, slightly shorter than basis of P 5; merus with slightly serrated antero-distal corner, slightly inflated anteriorly, maximum width almost 0.6 x length, slightly shorter than propodus, about 0.5 x basis; carpus relatively wide but more or less rectangular, length about 0.6 x propodus; anterior and distal margin of carpus and anterior margin of propodus, slightly serrated. P 7 basis with bulging posterior margin, length about 1.7 x maximum width, about 0.7 x basis of P 6; remaining articles together relatively long, almost 0.7 x basis; propodus with antero-distal corner produced into small, rounded lobe; dactylus sharp, hook-like. U 1 and U 2; endopod not fused with peduncle. U 1 peduncle relatively short, about 1.7 x length of exopod or only slightly longer; rami relatively slender, endopod slightly longer than exopod. U 2 endopod slightly longer than peduncle. Telson rounded, length marginally shorter than width at base. Description of allotype. Male, 5.2 mm. Like holotype female except for the following. Head relatively large, rounded, much deeper than long (about 1.5 x), as long as first 4 pereonites combined. A 1 callynophore without antero-distal corner; postero-distal corner small, rounded, separated from following article by distinct notch. Dactylus of G 1 and G 2 slightly longer, about 0.7 x propodus. P 5 length about 1.3 x P 4 and P 6; basis relatively longer about 2.4 x width. P 6 merus equal in length to propodus. P 7 basis more rectangular, length about 2 x width; length of remaining articles together slightly less than 0.4 x basis. U 1 peduncle slightly longer, about 2 x length of exopod. U 2 endopod slightly shorter than peduncle. Paratype USNM 1242790. Female, 3.7 mm. This specimen is in poor condition but is like the holotype except for the morphology of G 2 where the postero-distal corner of the carpus is relatively small, barely reaching to about one-third of the propodus (Fig. 10 A). However, this may be a juvenile character as noted for stage iv of L. pulex by Harbison (1976). Also, the dactylus of G 1 and G 2 is relatively shorter and less slender than for the holotype. Paratype SAMA C 12577. Female, 3.3 mm, recently moulted, immature. It is like the holotype in all respects except that the dactylus of G 1 and G 2 (Fig. 10 B) and P 3 – 6 are marginally longer and sharper. However, one might expect that the dactyls of recently moulted specimens might be less worn and hence slightly longer and sharper. Collected on the salp Cyclosalpa bakeri Ritter, 1905. Paratype NHMD- 619242. Female, 5.8 mm. Morphologically identical to the holotype. The dactylus of P 6, on the right, is partly retracted. Paratype NHMD- 228132. Female, 4.4 mm. Like the holotype. The dactylus of G 2 is marginally longer. Paratypes NHMD- 228242. Two females, 6.5 and 6.1 mm. Both are like the holotype except that the dactylus of G 2 is slightly longer and in the smaller specimen the postero-distal corner of the carpus of G 1 and G 2 is worn and both are more excavate, especially on the left side. The larger specimen is ovigerous. Paratypes NHMD- 228248. Two males, about 8.6 mm, one with head detached. Both with mature antennae and head with rounded knob as occurs in mature specimens of L. nasuta (Fig. 9), otherwise like the allotype. One specimen with the dactylus of P 6, on the right, fully retracted (Fig. 11).	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587CFFB5829D1E22FDC9F823.taxon	etymology	Etymology. I take great pleasure in naming this species for my colleague Dr Karen Osborn, Research Zoologist / Curator, Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington DC, in acknowledgement for her, and her team’s, research efforts investigating the evolutionary significance of vision and eye morphology in hyperiideans, and also for gaining the funds to enable me to spend two months at the Smithsonian in 2015, thus, in part, making this current review possible.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587CFFB5829D1E22FDC9F823.taxon	discussion	Remarks. Lycaea osbornae is most similar to L. lilia based on the morphology of G 2. It differs primarily in that the morphology of G 1 is like that of G 2 and in that the postero-distal corner of the carpus is pointed and the dactylus is relatively longer and slender (not stubby). In addition, the peduncle of U 1 is relatively shorter, less than 2 x the length of the exopod (about 2.5 x or more in L. lilia) and the telson is wider and more rounded in L. lilia. Also, in Lycaea osbornae the peduncle of U 2 is shorter than the endopod, a character only shared with L. pachypoda, L. pulex and males of L. serrata, all species from which L. osbornae is readily distinguished by the morphology of G 1 and G 2. An unusual character of this species is the retractile dactylus of P 6 which has not been found in any other species of Lycaea except L. intermedia but, as for that species, it is not evident in all specimens and can be difficult to determine unless the dactylus is at least partly retracted. One paratype (SAMA C 12577) from the N. E. Pacific was collected on the salp Cyclosalpa bakeri Ritter, 1905.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944587CFFB5829D1E22FDC9F823.taxon	distribution	Distribution. Known only from a few records, from the type locality, the north and S. E. Pacific and the S. E. Indian Ocean, as detailed above.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445870FFB3829D1AAEFE8DFE3F.taxon	description	(Figs 12 – 13)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445870FFB3829D1AAEFE8DFE3F.taxon	materials_examined	Type material. Type material of Pseudolycaea pachypoda could not be found in any major European institution and is considered lost. The type locality is the Mediterranean Sea, near Messina, Italy and the western Indian Ocean, near Zanzibar. Claus’s (1887) illustration of a female readily characterise this distinctive species. Material examined. In NHMD: numerous specimens from the Dana and Thor expeditions and others, too many to list here, from all the World’s Oceans including the Mediterranean Sea. In SAM: S. W. Atlantic: off South Africa [33 ° S 17 ° 19 ’ E & 35 ° 40 ’ S 18 ° 06 ’ E], 2 females (2 lots). In SAMA: S. W. Pacific, Tasman Sea, off central eastern Australia [about 34 ° – 43 ° S], 22 females, 14 males (9 lots), C 5265 – 73 and off eastern Tasmania [42 ° 45 ’ – 44 ° 14 ’ S], 15 females, 9 males (7 lots), C 12570 – 76. In USNM: N. W. Atlantic, Bermuda [31.93 ° N 63.77 ° W], 1 female, extracted from 1153747. N. E. Pacific, off Central America [12 ° 27 ’ N 111 ° 42 ’ W and 14.517 ° N 109.533 ° W], 2 females, 1264034, 1264063.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445870FFB3829D1AAEFE8DFE3F.taxon	diagnosis	Diagnosis. Body length of females up to 6.0 mm, males up to 7.0 mm. Body of females more globular than other congeners. Head of females relatively small, almost 2 x as deep as long, as long as first 3 pereonites combined. Head of males more rounded than in females, marginally longer. Buccal mass protruded well below head. Callynophore of A 1 of males without antero-distal corner; postero-distal corner small, rounded, barely partly over-lapping following article. G 1 and G 2 almost simple, morphologically similar, G 2 slightly longer than G 1. G 1 basis very broad, width about 0.5 x length, with inflated anterior margin; carpus sub-quadrate with slightly serrated postero-distal corner, extending slightly posterior to propodus; propodus with postero-distal corner produced posteriorly to dactylus; dactylus robust, length about 0.5 x propodus. G 2 similar to G 1 but basis more slender and longer, carpus slightly narrowed distally and postero-distal corner of propodus is smaller. P 3 – 6 with relatively short, stubby dactylus, those of P 3 and P 4 only about 0.2 x propodus. P 3 and P 4 morphologically similar, P 4 marginally longer than P 3; merus slightly inflated anteriorly, length sub-equal to propodus or slightly longer, about 0.5 x basis; carpus sub-equal in length to propodus. P 5 only slightly longer than P 6, about 1.3 – 1.4 x P 4; basis rectangular, length 1.6 x maximum width (marginally less in males); merus marginally inflated anteriorly, slightly shorter than propodus, about 0.5 x length basis; carpus length about 0.8 x propodus. P 6 basis relatively broad, length 1.4 x maximum width, almost as long as basis of P 5; merus broader than for P 5, maximum width about 0.6 x length, sub-equal in length to propodus, marginally longer than 0.4 x basis; carpus slightly inflated, length marginally less than 0.8 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin (more proximally in females), length about 1.8 x maximum width, slightly more than 0.8 x basis of P 6; length of remaining articles 0.5 – 0.6 x basis; propodus with antero-distal corner produced into rounded lobe; dactylus sharp, hook-like. U 1 and U 2; endopod not fused with peduncle. U 1 peduncle length about 2.0 x exopod; endopod slightly broader than endopod, equal in length. Telson length about 1.4 x width at base, or marginally shorter.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445870FFB3829D1AAEFE8DFE3F.taxon	discussion	Remarks. Lycaea pachypoda is readily distinguished from all its congeners by the morphology of G 1 and G 2, which are almost simple. Prior to Vinogradov et al. (1982, 1996) this species was relegated to the monotypic genus Pseudolycaea Claus, 1879. However, apart from G 1 and G 2, it is very similar to other species of Lycaea and the generic distinction cannot be maintained. Like L. pulex, L. pachypoda has been recorded from the salp Salpa maxima and pyrosomes (Chevreux 1892, 1900; Chevreux & Fage 1925; Laval 1980). It has also been recorded from the medusa Liriope tetraphylla (Chamisso & Eysenhardt, 1821) (Harbison et al. 1977).	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445870FFB3829D1AAEFE8DFE3F.taxon	distribution	Distribution. A relatively uncommon species but widely distributed in the tropical and temperate regions of all the world’s oceans, including the Mediterranean Sea, generally between the Subtropical Convergences. Vinogradov (1962) also records it from the Southern Ocean, off Australia, at about 45 ° S. Most catch records are from nearsurface waters.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445875FF8C829D1BE2FA97F90B.taxon	description	(Figs 14 – 15)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445875FF8C829D1BE2FA97F90B.taxon	materials_examined	Material examined. Holotype. Male, 7.0 mm, USNM 1246984. Tropical W. Atlantic, N. E. of French Guiana [08 ° N 44 ° W], R / V Gilliss, USNOO Expedition stn. 2 - T 1 - C, trawl 10 feet, Farquhar, 20 January 1969. Allotype. Female, 6.2 mm, NHMD- 228266, Dana stn. 3920 vii, S. W. Indian Ocean, N. E. of Seychelles [01 ° 12 ’ S 62 ° 19 ’ E], 600 mw, 9 December 1929. Paratypes. All from the following Dana stations. Indo-Pacific: 2 females, 1 male, NHMD- 228250, 3734 iii [11 ° 43 ’ N 121 ° 03 ’ E], 300 mw, 27 June 1929; 5 females, 5 males, NHMD- 228252, 3800 iii [07 ° 53 ’ S 116 ° 18 ’ E], 300 mw, 18 August 1929; 4 females, NHMD- 288253, 3800 v [07 ° 53 ’ S 116 ° 18 ’ E], 50 mw, 18 August 1929. Indian Ocean, from Bali to South Africa: 1 female, 1 male, NHMD- 228260, 3908 v [04 ° 28 ’ N 81 ° 13 ’ E], 100 mw, 22 November 1929; 1 male, NHMD- 228264, 3918 iv [00 ° 35 ’ N 66 ° 09 ’ E], 300 mw, 7 December 1929; 2 females, NHMD- 619991, 3920 vii [01 ° 12 ’ S 62 ° 19 ’ E], 600 mw, 9 December 1929; 3 females, 3 males, NHMD- 228270, 3921 viii [03 ° 36 ’ S 58 ° 19 ’ E], 100 mw, 11 December 1929; 6 females, 3 males, NHMD- 228271 – 2, 3924 iv – v [05 ° 01 ’ S 54 ° 46 ’ E], 100 & 50 mw, 14 December 1929; 4 females, 4 males, NHMD- 228273 – 4, 3925 iv – v [07 ° 13 ’ S 52 ° 22 ’ E], 100 & 50 mw, 16 December 1929; 1 male, NHMD- 228277, 3937 i [09 ° 26 ’ S 46 ° 05 ’ E], 500 mw, 22 December 1929; 1 female, NHMD- 228279, 3938 i [09 ° 10 ’ S 45 ° 17 ’ E], 500 mw, 23 December 1929; 4 females, 1 male, NHMD- 228282 – 3, 3941 i – ii [07 ° 24 ’ S 41 ° 51 ’ E], 500 & 400 mw, 24 December 1929; 2 females, NHMD- 228286 – 7, 3942 ii, 3942 v [06 ° 47 ’ S 41 ° 27 ’ E], 400 & 100 mw, 25 December 1929; 3 females, NHMD- 228288 – 9, 3954 ii – iii [16 ° 53 ’ S 42 ° 12 ’ E], 300 & 200 mw, 9 January 1930; 1 female, 1 male, NHMD- 228290 – 1, 3957 ii, 3957 v [21 ° 30 ’ S 42 ° 32 ’ E], 300 & 50 mw, 11 January 1930. Tropical Atlantic: 2 males, NHMD- 228294, 3997 ii [11 ° S 07 ° 36 ’ W], 600 mw, 27 February 1930; 1 female, NHMD- 228300, 3998 iv [07 ° 34 ’ S 08 ° 48 ’ W], 100 mw, 1 March 1930; 1 male, NHMD- 620067, 4001 iv [03 ° 56 ’ N 12 ° 32.5 ’ W], 100 mw, 6 March 1930. Additional male from S. W. Indian Ocean, off South Africa, SAMA C 12600, Meiring Naude stn. SM 152 D [30 ° 13 ’ 30 ” S 31 ° 27 ’ 30 ” E], 212 m, 17 May 1977. Other material: All from the following Dana stations, mostly in poor condition. Atlantic Ocean: 1 male, NHMD- 228240, 946; 4 females, 4 males, NHMD- 228295, 3997 iv; 1 female, NHMD- 228299, 3997 v; 8 females, NHMD- 228301, 3998 v; 5 females, NHMD- 288302, 4000 iv; 1 female, NHMD- 288303, 4000 x. Pacific Ocean: 1 female, 1 male, NHMD- 228243, 1208 xiv; 1 female, NHMD- 228249, 3620 v. Indian Ocean: 2 females, 2 males, NHMD- 228246 – 7, 3556 v – vi; 1 male, NHMD- 228254, 3804 iii; 2 females, 1 male, NHMD- 228261, 3913 v; 1 female, NHMD- 228265, 3918 v; 3 females, NHMD- 228267, 3920 viii; 3 females, 1 male, NHMD- 228269, 3921 vii; 4 females, NHMD- 228278, 3937 iii; 1 female, NHMD- 228281, 3939 ii.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445875FF8C829D1BE2FA97F90B.taxon	description	Description of holotype. Male, 7.0 mm. Head sub-spherical, with small rounded knob anteriorly, about 1.3 x as deep as long, as long as first 4.5 pereonites combined. Buccal mass barely protruding below head. Callynophore of A 1 without antero-distal corner; postero-distal corner small, rounded, partly over-lapping following article. G 1 and G 2 sub-chelate, G 2 slightly longer than G 1. G 1 basis marginally inflated; merus with relatively straight distal margin, not v-shaped as in all other congeners; carpus sub-rectangular, about as wide as long, with small, sharp, postero-distal tooth; postero-distal corner of propodus not produced posteriorly to dactylus; dactylus relatively long and slender, almost as long as propodus. G 2 very similar to G 1 except carpus is more rectangular, slightly longer than wide. P 3 – 6 with relatively short, slender dactylus, those of P 3 and P 4 about 0.2 x propodus, or slightly more. P 3 and P 4 morphologically similar, P 4 marginally longer than P 3; merus not inflated anteriorly as in other species, sub-equal in length to propodus, about 0.6 x basis; propodus length 1.2 – 1.3 x carpus. P 5 length about 1.3 x P 4, 1.2 x P 6; basis rectangular, relatively slender, length about 2 x maximum width; merus sub-equal in length to propodus, almost 0.7 x basis; carpus length about 0.7 x propodus. P 6 basis oval-shaped, with evenly convex margins, length about 1.5 x maximum width; merus length about 0.5 x basis, slightly shorter than propodus; carpus length about 0.8 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis almost spherical, marginally longer than wide, length about 0.6 x basis of P 6; length of remaining articles less than 0.3 x basis; dactylus sharp, hook-like. U 1 and U 2; endopod not fused with peduncle. U 1 peduncle length about 3.0 x exopod; rami equal in length. Telson relatively narrow, length about 1.6 x width at base, with slight, but distinct, concavity on the margins, about one-third from the tip, apex evenly rounded, almost pointed. Description of allotype. Female, 6.2 mm. Like holotype except for the following. Head relatively deep, almost 1.7 x as deep as long, as long as first 4 pereonites combined, without anterior knob. Dactylus of G 1 and G 2 slightly shorter, about 0.8 x propodus. P 7 basis more elongate, length about 1.5 x width. Telson without concavity on margins, length only 1.3 x width at base. Variations. The excavation of the carpus of G 1 and G 2 can vary slightly, sometimes approaching that of L. serrata, especially in some females, and the propodus is often extended slightly beyond the postero-distal corner of the carpus.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445875FF8C829D1BE2FA97F90B.taxon	etymology	Etymology. This species is named “ proserrata ” (from the latin “ pro ”, just as) to indicate that it closely resembles L. serrata in that G 1 and G 2 have a long dactylus and the propodus lacks the characteristic postero-distal corner, and in that the articles distal to the basis of P 7 are together relatively short. The morphology of G 1 and G 2 sometimes approaches that of L. serrata.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445875FF8C829D1BE2FA97F90B.taxon	discussion	Remarks. It is with some hesitation that I describe this species as new to science but it has a number of characters that cannot be easily reconciled with any other species. The morphology of the male A 1, lacking an antero-distal corner, alone distinguishes it from L. bovallii and L. vincentii. The morphology of G 1 and G 2 readily distinguish it from L. lilia and L. osbornae and also from L. pulex which have shorter dactyls and the propodus has a distinct, slightly serrated, postero-distal corner. Also, L. pulex is distinguished by the relatively short peduncle of U 1. This species also bears some resemblance to L. nasuta but is readily distinguished from it by the longer dactylus of G 1 and G 2, the morphology of G 2, the relatively longer and more slender telson and in that the endopod of U 2 is not fused with the peduncle. Thus, L. proserrata is most similar to L. serrata and it is likely that the two have been confused in the past. However, in L. serrata the carpus of G 1 and G 2 is distinctly more excavate, and although this character can vary slightly with the excavation ranging from moderate to extreme, usually more extreme for G 1, it is usually greater than found in L. proserrata. Also, males of L. proserrata are readily distinguished by the more slender habitus (compare figs 14 and 19) and are further distinguished from L. serrata by the following characters of that species: i) specimens of similar size, have a smaller head without an anterior knob; ii) the buccal mass extends well below the head; iii) some of the pereonites and pleonites are denticulate; iv) the merus and carpus of P 5 are relatively broad (even in smaller specimens 5 – 6 mm); v) the dactylus of P 7 is vestigial; vi) the peduncle of U 1 is relatively short (only 2 x exopod); and vii) the telson is only marginally longer than wide; characters that are all at odds with L. proserrata. The long, relatively narrow, telson of L. proserrata males is especially distinctive, often with a slight concavity on the margins, about one-third from the tip. An unusual character noted for this species is that the distal margin of the merus of G 1 and G 2 is relatively straight, not v-shaped, over-lapping the carpus, which is characteristic of all other congeners. This character seems to be consistent in all the specimens examined and readily distinguishes this species. It is especially useful in distinguishing females from smaller (<9 mm) specimens of L. serrata in which the pereonites and pleonites are often only slightly carinate. Large females of L. serrata (> 9 mm) are easily distinguished by the inflated pereonites and the raised dorsal corners of the pleonites (fig. 18). This is one of the smaller species of Lycaea, with females mature at about 5 – 7 mm and males at 6 – 9 mm. One female (NHMD- 228295) is ovigerous at 5.2 mm. A gelatinous associate has not been recorded.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445875FF8C829D1BE2FA97F90B.taxon	distribution	Distribution. The Dana collections, as detailed above, indicate that this species is widely distributed in the tropical regions of the Atlantic, Pacific and Indian Oceans. It seems to be most common in the Indian Ocean.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584AFF8E829D1D36FA85F89F.taxon	description	(Figs 16 – 17)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584AFF8E829D1D36FA85F89F.taxon	materials_examined	Type material. Type material of Lycaea pulex could not be found in any major European institution and is considered lost. The type locality is the Mediterranean Sea, Gulf of Marseille. Despite the apparent loss of the type material, this is a relatively well known species, readily characterised by the description and figures provided by Marion (1874). Type material of synonyms. Type material of Lycaea robusta could not be found in any major European institution and is considered lost. The type locality is the Mediterranean Sea, off Naples and Messina. Claus’s (1887) illustrations of this species, especially of the male A 1 and G 1 and G 2, confirm the synonymy, although the peduncle of U 1 is illustrated as relatively long. Type material of Lycaea similis could not be found in any major European institution and is considered lost. The type locality is the tropical W. Atlantic, off Lagos. Claus’s (1887) illustrations of this species, especially of G 1 and G 2, the relatively short dactyls and U 1, confirm the synonymy. The unique holotype male (7.6 mm) of L. pauli is in the NHM, London (89.5.15.248); on one microscope slide. The condition of the material is very poor and it is difficult to determine the species with certainty, but it is considered a synonym of L. pulex based on the short dactyls, the strongly sub-chelate G 1 and G 2 and the relatively shorter peduncle of U 1. The type locality is the mid-Atlantic Ocean, off St. Paul’s Rocks [01 ° 10 ’ N 28 ° 23 ’ W], Challenger stn. 108, surface, 27 August 1873. Material examined. The holotype male of Lycaea pauli as detailed above and the following. In NHMD: tropical Atlantic near Bahamas and southern central, Dana stn. 1243 iii (228142), 1 female; Dana stn. 1165 iii (228241), 1 female. N. E. Atlantic, 8 females, 2 males, Thor stns 377, 399, 400. Mediterranean Sea, 9 females, 2 males (6 lots), Thor stns 10, 160 - 3, 186, 216. Central S. Pacific, Dana stns 3585 xi, 3587 viii (228160, 619244), 2 females. E. Indian Ocean, off Sumatra, Dana stn. 3817 iv (228174), 1 female. S. of Japan, Jutlandia stn. 4775 (228237), 2 females. In SAM and SAMA (part): Meiring Naude collections from S. W. Indian Ocean, off South Africa, between Kosi Bay and just south of East London, 11 females, 8 males (14 lots), 250 – 45 m. In SAMA: S. W. Pacific, Tasman Sea, off central eastern Australia to eastern Tasmania [about 33 ° – 44 ° S], 16 females, 5 males (12 lots), C 5274 – 82 (excl. 77) and C 12578 – 81, 250 – 0 m. S. Australia, Pearson Island, 1 female, C 12582. S. W. Atlantic, off Brazil [23 ° 28 ’ S 41 ° 57 ’ W], 5 females, 3 males, C 12583. N. E. Pacific, region off BC Canada, 19 females 17 males (10 lots), C 12584 – 94 (excl. 92); off San Francisco, 1 female, C 12595. In USNM: N. W. Atlantic, from French Guiana in the south, north to Georges Bank, off Massachusetts, 17 females, 9 males (19 lots), 12873, 264108, 1178034, 1241232, 1241237, 1241243 – 4, 1241285, 1241287 – 8, 1242772, 1242786, extracted from 1242794, 1242808, 1246971, 1246976, 1246991, 1253862, 1277467. S. W. Atlantic, off Brazil, 6 females, 2 males, 10 juveniles (4 lots), 1246965, 1246982 – 3, 1247117. N. E. Pacific, off Central America, 1 female, 3 males (3 lots), 1242802, 1247124, 1253890. S. E. Pacific, off Chile [22 ° 54 ’ S 77 ° 10 ’ W], 1 female, 1246962; near Galapagos Islands [00 ° 02 ’ S 96 ° 02 ’ W], 75 males (night light), 1247123. Japan, Kyushu Island [31 ° 19 ’ N 132 ° 11 ’ 30 ” E], 6 males, extracted from 1242796.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584AFF8E829D1D36FA85F89F.taxon	diagnosis	Diagnosis. Body length up to 9.0 mm. Head of females relatively large, deeper than long, as long as first 4 pereonites combined. Head of males more rounded, slightly deeper than long, as long as first 3.5 pereonites combined. Buccal mass protruded well below head. Callynophore of A 1 of males without antero-distal corner; postero-distal corner small, rounded, partly over-lapping following article. G 1 and G 2 sub-chelate, morphologically similar, G 2 slightly longer than G 1; basis of G 1 slightly broader and shorter than G 2; carpus rectangular with sharp postero-distal tooth, reaching just past base of dactylus, especially in males; propodus with postero-distal corner produced posteriorly to dactylus; carpus and propodus with small serrations on distal margin; dactylus slender, length about 0.5 x propodus. P 3 – 6 with relatively short, stubby dactylus, those of P 3 and P 4 only about 0.2 x propodus. P 3 and P 4 morphologically similar, P 4 slightly longer than P 3; merus slightly inflated anteriorly, sub-equal in length to propodus, about 0.5 x length basis; carpus length about 0.8 – 0.9 x propodus. P 5 only slightly longer than P 4 or P 6; basis rectangular / oval, length 1.5 – 1.7 x maximum width; merus marginally inflated anteriorly, sub-equal in length to propodus, about 0.6 x basis; carpus length about 0.7 – 0.8 x propodus. P 6 basis length 1.5 – 1.7 x maximum width, more oval-shaped than P 5 but equal in length; merus, carpus and propodus similar in relative lengths to P 5; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin, length about 1.5 x maximum width, about 0.8 x basis of P 6; length of remaining articles slightly shorter than 0.5 x basis; propodus without antero-distal corner produced into rounded lobe; dactylus sharp, hook-like. U 1 and U 2; endopod not fused with peduncle. U 1 peduncle length about 2.0 x exopod or slightly less; rami relatively slender, equal in length. Telson length about 1.5 x width at base.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584AFF8E829D1D36FA85F89F.taxon	discussion	Remarks. Lycaea pulex is one of the larger species of Lycaea reaching maturity at about 9.0 mm or slightly less. It is best distinguished from its congeners by the relatively short peduncle of U 1 (about 2.0 x length exopod) and the very short dactylus of P 3 – 6. Amongst the ‘ short dactylus’ group it is readily distinguished by the morphology of G 1 and G 2 alone; the relatively shorter peduncle of U 1 also distinguishes it from the remaining two congeners, L. bovallii and L. vincentii. Harbison (1976) gives a more detailed account of this species. Many of the species of Lycaea recognised by Harbison & Madin (1976) have, at times, been confused with this species. Most of this confusion is because of the poor descriptions and illustrations, generally, of species in the literature. Also, Vinogradov et al. (1982, 1996), in their illustration of L. pulex, borrow the figure of the habitus and male antenna from Stebbing’s (1888) illustration of L. vincentii that they regard a synonym but which is now considered a valid species. Hence, some of the species listed in the literature as Lycaea pulex, in the above list, may be mis-identifications. Of note is one relatively large (7.6 mm) female specimen from the central mid-Atlantic (NHMD- 228241), with a very large head, almost as long as the pereon. Apart from the head it is like other specimens of L. pulex and has been determined as such for the time being. It has been recorded in association with a variety of salps, Cyclosalpa pinnata, Pegea confoederata (Harbison 1976); Cyclosalpa affinis, C. bakeri, C. pinnata, Helicosalpa komaii (Ihle & Ihle-Landenberg, 1936), Ihlea punctata (Forsskål, 1775), Pegea socia, P. bicaudata (Quoy & Gaimard, 1826), P. confoederata, Salpa cylindrica, S. maxima and Traustedtia multitentaculata (Quoy & Gaimard, 1834) (Madin & Harbison 1977). And, like L. pachypoda, it has also been recorded from Salpa maxima and pyrosomes (Chevreux 1892, 1900; Chevreux & Fage 1925; Laval 1980). However, because of the confusion of this species with others in the past, it is likely that some of these associations refer to other species of Lycaea.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584AFF8E829D1D36FA85F89F.taxon	distribution	Distribution. This is one of the most commonly recorded species of Lycaea but determining its distribution precisely from the literature is problematical because of the past confusion with other congeners. However, it seems to be relatively common and widespread in tropical and warm-temperate regions of all the world’s oceans, including the Mediterranean Sea. Most records are from the 0 – 500 m layer but it seems to prefer near-surface waters.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584DFF84829D1AAEFED3FB73.taxon	description	(Figs 18 – 19)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584DFF84829D1AAEFED3FB73.taxon	materials_examined	Type material. Type material of Lycaea serrata could not be found in any major European institution and is considered lost. The type locality is the Bay of Bengal. Claus’s (1887) illustration of a male readily characterise this distinctive species. Type material of synonyms. The three female syntypes of Metalycaea globosa are in the NHMD, all labelled “ Type ” in alcohol. The specimens were collected by the Thor from the Mediterranean Sea, stn. 112 [36 ° 56 ’ N 02 ° 15 ’ E], 25 mw, 27 June 1910 (NHMD- 84411, previously CRU- 6567); stn. 118 [41 ° 00 ’ N 06 ° 43 ’ E], 65 mw, 30 June 1910 (NHMD- 86800, previously CRU- 9301) and stn. 160 [35 ° 59 ’ N 28 ° 14 ’ E], 1000 mw, 1 August 1910 (NHMD- 86799, previously CRU- 9300). The specimen from stn. 118 is illustrated by Stephensen (1925). An examination of this material has proven that it is indistinguishable from mature female specimens of L. serrata. Material examined. The type material of Metalycaea globosa as detailed above and the following. In NHMD: Mediterranean Sea, 9 males (7 lots), Dana stns 1123 iv, 4050 v, 4060 and Thor stns 134, 144, 183, 339. N. E. Atlantic, 5 females (3 lots) Dana stns 4001 iv (228304), 4004 v (228306), 4005 x (228307). S. W. Atlantic, 20 females, male (3 lots), Dana stns 1231 iv (228245), 3997 iv-v (620062, 228297); additional Dana material from the Atlantic, 12 females, 1 male (10 lots) from stns 1145 vii, 1189, 1239, 1320, 1364, 3978 x, 3997 iii, 3998 iii, 4001 iv, 4010 ii. Indian Ocean from Sumatra to South Africa, 55 females, 26 males (43 lots), Dana stns 3814 i, 3850 i, 3850 iii, 3857 iii, 3893 iii, 3903 iv-v, 3915 iii, 3918 iii, 3919 iv, 3920 viii, 3921 ii-iii, 3921 vi, 3922 iii-iv, 3924 ii, 3925 ii-v, 3926 i, 3926 iv, 3928 i, 3928 v, 3929 iv, 3932 vi, 3937 ii, 3939 ii, 3938 ii, 3941 i-iv, 3956 iii, 3957 i, 3959 i-iii, 3962 iii, 3965 i-ii, 3971 ii-iii. Tropical Pacific, 22 females, 14 males (25 lots), Dana stns 3553 i, 3556 ii, 3558 vi-vii, 3561 v, 3563 ii, 3593 iii, 3616 v, 3620 iii, 3622 iii, 3623 iv, 3624 x, 3626 iv, vi, viii, ix, 3651 vi-vii, 3655 iv, 3722 iii, 3724 i, 3800 ii-iii, 3814 i. In SAM and SAMA (part), Meiring Naude collections from S. W. Indian Ocean, off South Africa, just north of East London, 4 females, 1 male (4 lots), 244 – 0 m. In SAMA: Tasman Sea, off eastern Tasmania [42 ° 47 ’ 50 ” S 148 ° 50 ’ E], 1100 – 0 m, 2 females, C 12082. S. W. Atlantic, off Brazil [03 ° 29.95 ’ S 32 ° 30.49 ” W], 5 juveniles (doubtful ID), C 12601. In USNM: N. W. Atlantic, from French Guiana in the south, north to Georges Bank, off Massachusetts, 6 females, 3 males (8 lots), 108048 – 9, 1154681, 1241175 – 7, 1246985, 1246989. S. W. Atlantic, off Brazil [08 ° 02 ’ S 24 ° 59 ’ W], 64 m, 1 female, 1246981.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584DFF84829D1AAEFED3FB73.taxon	diagnosis	Diagnosis. Body length of mature females up to 16.0 mm and males up to 9.0 mm. Head of females ovalshaped, almost 2 x as deep as long, as long as first 4 pereonites combined. Head of males relatively smaller than females, 2 x as deep as long, almost as long as first 4 pereonites combined. Buccal mass protruded well below head. Callynophore of A 1 of males without antero-distal corner; postero-distal corner small, rounded, partly over-lapping following article. Mature females with pereonites inflated, resembling transverse rollers (as in Iulopis), progressively more raised dorsally; pleonites also with raised dorsal corners. Mature males and immature females with dorsal corners of pereonites 4 – 7 only slightly raised; pleonites 1 – 2 may also have slightly raised dorsal corners. G 1 and G 2 sub-chelate, G 2 about 1.5 x as long as G 1. G 1 basis inflated anteriorly with evenly rounded anterior margin; carpus trapezoid, with obliquely excavate distal margin, with small, sharp, postero-distal tooth; postero-distal corner of propodus not produced posteriorly to dactylus; dactylus relatively long and slender, length about 0.8 x propodus. G 2 carpus slightly less excavate than G 1; propodus and dactylus like that of G 1. P 3 – 6 with relatively short, slender dactylus, those of P 3 and P 4 about 0.2 x propodus, or slightly less. P 3 and P 4 morphologically similar, P 4 marginally longer than P 3; merus slightly inflated anteriorly, slightly longer than propodus and about 0.5 x length basis; propodus slightly longer than carpus, with slight postero-distal excavation and slightly serrated margin. P 5 of very large females like that of males, otherwise as follows; length about 1.2 x P 4, 1.3 x P 6; basis rectangular, relatively slender, length slightly more than 3 x maximum width; merus relatively long and slender, length about 1.6 x propodus, almost 0.7 x basis; carpus sub-equal in length to propodus. P 5 of males; length almost 1.4 x P 4, about 1.3 x P 6; basis rectangular, relatively slender, length almost 3 x maximum width; merus with distinct anterior bulge, especially in mature specimens, length 1.4 x propodus, slightly more than 0.6 x basis; carpus also with distinct anterior bulge, sub-equal in length to propodus; propodus with slight serrations on anterior margin. P 6 basis pear-shaped, especially in females where the length is about 1.4 x maximum width; merus length about 0.5 x basis, about 1.2 x propodus; carpus length about 0.8 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin, length about 1.8 x maximum width, about 0.7 x basis of P 6 in males, almost as long as basis of P 6 in females; length of remaining articles less than 0.2 x basis; dactylus degenerative or absent. U 1 and U 2 endopod not fused with peduncle. U 1 peduncle length about 2.0 x exopod in females, slightly less in males; rami equal in length. Telson slightly longer than width at base, with evenly rounded, almost pointed apex.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584DFF84829D1AAEFED3FB73.taxon	discussion	Remarks. Lycaea serrata is the largest and one of the most distinctive species of Lycaea. Apart from the obliquely excavate carpus of G 1 and G 2, it is easily distinguished by a number of unusual characters. In particular, in mature females the pereonites are characteristically inflated resembling transverse rollers (similar to Iulopis) and the dorsal corners of the pleonites are also significantly raised. In mature males, and to a lesser extent in juvenile males and females, some pereonites (usually 4 – 7) and the first two pleonites are carinate. Also, in mature males and very large females the merus and carpus of P 5 is distinctly inflated. In addition, the propodus of P 3 and P 4 has a slight postero-distal excavation; the basis of P 6 is pear-shaped and the distal articles of P 7 are together much shorter than the basis, with a degenerative dactylus. The degree of the excavation of the carpus of G 1 and G 2 can vary slightly but is always more extreme in G 1. The discovery of L. proserrata amongst collections identified as L. serrata indicate that more species may be determined amongst the “ serrata ’ group with a more detailed analysis of the gnathopod morphology and other characters. Its similarity to L. proserrata is discussed under that species. A salp associate has not been recorded for this species.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F1944584DFF84829D1AAEFED3FB73.taxon	distribution	Distribution. This appears to be mainly a tropical species having been recorded from the tropical regions of all three oceans and the Mediterranean Sea. It has also been recorded from the warmer parts of the North Atlantic, as far as 41 ° N.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445842FF87829D1F2EFA59F84E.taxon	description	(Figs 20 – 21)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445842FF87829D1F2EFA59F84E.taxon	materials_examined	Type material. The unique holotype male (about 5 mm) of Lycaea vincentii is in the NHM, London (89.5.15.309), on two microscope slides. The type locality is the N. E. Atlantic, off St Vincent, Cape Verde Islands [16 ° 49 ’ N 25 ° 14 ’ W], Challenger, surface, 26 April 1876. Type material of synonyms. Type material of Amphipronoe longicornuta, consisting of one female and one male (whole but dry), is in the NHM, London (1909.4.3.6), on one microscope slide. The type locality is the Bay of Bengal. Barnard (1930) suggested that this species may be synonymous with L. bajensis. Harbison et al. (1976), on the other hand, consider it to be near L. vincentii. An examination of the type material has confirmed the latter synonymy. Material examined. Type material of Lycaea vincentii and Amphipronoe longicornuta as detailed above and the following. In NHMD: S. E. Atlantic, off Angola, Galathea stn. 98 [08 ° 52 ’ S 11 ° 09 ’ E], 2820 m, 3 females, 6 males, “ with salps ”. Tropical Pacific, Dana stn. 3722 v, S. E. of Taiwan [25 ° 11 ’ N 122 ° 35 ’ E], 50 mw, 1 female; Galathea stn. 745, Gulf of Panama [07 ° 15 ’ N 79 ° 25 ’ W], 935 m, 2 females, 2 males. In SAMA: Coral Sea, Great Barrier Reef, north-east of Townsville, 44 females, 21 males (23 lots), C 12622 – 44. Tasman Sea, off eastern Australia [20 ° – 40 ° S], 13 females, 8 males (16 lots), C 5283 – 99. In USNM: N. W. Atlantic, from the Sargasso Sea in the south, north to Delaware Bay, 8 females, 18 males (9 lots), 12880, 108144, 181802, 1178021, 1241178, 1246975, 1246980, 1242792, 1242794. S. W. Atlantic, off Brazil [02 ° 07 ’ N 44 ° 02 ’ W], 1 male, 1246987. N. Pacific, Hawaii [23 ° 19 ’ N 166 ° 54 ’ W], 1 male, 1242805. Japan, Colnett Strait, S. W. of Yaku Shima, 5 males, 1246963.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445842FF87829D1F2EFA59F84E.taxon	diagnosis	Diagnosis. Body length up to 6.0 mm. Head of females relatively large, deeper than long, as long as first 4 pereonites combined. Head of males more rounded, slightly elongated, marginally deeper than long, almost as long as first 5 pereonites combined. Buccal mass protruded well below head. Callynophore of A 1 of males with distinct antero-distal corner, set back slightly from distal margin; postero-distal corner small, acutely rounded, separated from following article by distinct notch. G 1 and G 2 sub-chelate, morphologically similar, G 2 slightly longer than G 1; basis of G 1 slightly broader and shorter than G 2; carpus rectangular with sharp postero-distal tooth, reaching just past base of dactylus; propodus with postero-distal corner produced posteriorly to dactylus; carpus and propodus with small serrations on distal margins, those on posterior margin of carpus of G 1 prominently scalloped; dactylus slender, length about 0.6 x propodus, or marginally longer in females. P 3 – 6 with relatively slender dactylus of moderate length, those of P 4 about 0.3 – 0.4 x propodus. P 3 and P 4 morphologically similar, P 4 slightly longer than P 3; merus slightly inflated anteriorly, sub-equal in length to propodus, about 0.6 x basis; carpus length about 0.6 – 0.7 x propodus. P 5 slightly longer than P 4 or P 6; basis rectangular / oval, length 1.8 – 2.0 x maximum width; merus sub-equal in length to propodus, about 0.6 – 0.7 x basis; carpus length about 0.7 x propodus. P 6 basis more oval-shaped than P 5 but almost equal in length, slightly broader in males with length 1.5 x maximum width (2.0 x in females); merus sub-equal in length to propodus, about 0.4 x basis; carpus length about 0.5 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin, more prominent in males, length about 1.4 x maximum width in males (about 1.7 x in females), length about 0.7 x basis of P 6 for both sexes; length of remaining articles about 0.3 x basis; propodus with antero-distal corner produced into small, rounded lobe; dactylus sharp, hook-like. U 1 and U 2; endopod not fused with peduncle. U 1 peduncle length 3.5 x exopod, or slightly more; rami relatively slender, equal in length. Telson as long as width at base in males, slightly longer in females.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445842FF87829D1F2EFA59F84E.taxon	discussion	Remarks. In the past, Lycaea vincentii has been considered a synonym of L. pulex, but it is distinguished by the medium length dactylus of P 3 – 6, and the relatively long peduncle of U 1 (see Harbison 1976). Males are further distinguished by the distinctive antero-distal bulge of the callynophore of A 1 which is absent in all other congeners except for L. bovallii. It is also a relatively smaller species reaching maturity at 5 – 6 mm, compared to 9 mm for L. pulex. Another distinctive character is that the posterior margin of the carpus of G 1 is distinctly scalloped rather than serrated, a character not found in any other species except perhaps L. bovallii, but in that species the margin is more serrated than scalloped and is much less prominent. Clearly Lycaea vincentii is most closely related to L. bovallii but is distinguished by the characters as discussed under that species. Regarding Amphipronoe longicornuta Giles, 1888 the date given for this reference is often 1887 which would predate L. vincentii Stebbing, 1888 and create a potential nomenclatural problem. However, this species has not been reported since its original description and the volume containing Giles’s description was not published until 1888, the volume being “ for the year 1887 ”. The only recorded associates are with the salps Salpa cylindrica and Thalia democratica (Forsskål, 1775) (Harbison 1976) and also Pegea confoederata (Madin & Harbison 1977). Diebel (1992) provides some interesting information on the integumentary sensilla.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445842FF87829D1F2EFA59F84E.taxon	distribution	Distribution. Difficult to determine because of the past confusion with other species. However, it is probably widespread in the tropical and temperate regions of the Pacific and Atlantic. It is relatively common off the eastern coast of Australia. Other reliable records are from the northern Atlantic, the N. E. Pacific and the South China Sea.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445846FF80829D18EEFB74FBA4.taxon	discussion	Type material. Type material of Daira depressa is considered lost (see Evans 1967). The type locality is the S. W. Pacific, west of Savaii, Samoa, 15 m, 15 March 1841. The description given by Dana (1853) is inadequate, and the figures too small, lacking in detail, to enable a determination of this species. Dana (1853) illustrates G 1 and G 2 with serrations on the posterior margin of the carpus, more typical of the genus Brachyscelus, but the description is more consistent with Lycaea, particularly in that Dana (1853) notes there are no serrations “ on the palm ”. Some species of Lycaea such as L. bovallii and L. vincentii have gnathopods with slight serrations on the posterior margin of the carpus but they are not as prominent as illustrated by Dana (1853).	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445846FF80829D1E06FDEAFA87.taxon	discussion	Type material. Type material of Hyperia pupa could not be found in any major European institution and is considered lost. The type locality is the Mediterranean Sea, off the coast of Naples. Costa’s description of this species is very inadequate and in 1857 he only illustrates a gnathopod and part of the pleon. Stebbing (1888) considered it a probable species of Lycaea.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445846FF80829D1F66FA81F9BF.taxon	discussion	Type material. Type material of Lycaea stebbingi could not be found in the NRS or NHMD and is considered lost. No precise type locality is given; just “ tropical parts of Atlantic ”. The description provided by Bovallius (1887) is very inadequate and there are no figures. Therefore, in the absence of type material, it is impossible to determine the status of this species. Vinogradov et al. (1982, 1996) consider it a synonym of L. serrata.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445846FF80829D181AFB8CFD1C.taxon	discussion	Type material. As for the previous species. This figure was obviously not good enough for Fabricius to name the species in his 1775 work, and it has not been referred to by later naturalists. The illustration is very similar to the previous species and possibly represents a juvenile Lycaea or Brachyscelus.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445846FF80829D1AE6FDA8FE40.taxon	discussion	Type material. Zeidler (1995) established that Fabricius (1775) based his original description of this species solely on drawings made by Sydney Parkinson, labelled “ Onidium gibbosum ”, now held by the NHM, London. An examination of these drawings suggest that this is most likely a species of Lycaea, but that the drawings, and description, lack sufficient detail to make a specific determination. The type locality is the Atlantic Ocean, near Portugal, inside a salp (Dagysas sp.).	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445846FF83829D1C62FE89FABB.taxon	type_taxon	Type species. Simorhynchus antennarius Claus, 1871 by monotypy. Type material could not be found in any major European institution and is considered lost. However, the description and figures provided by Claus (1871, 1879, 1887) for this species, readily characterise this genus.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445846FF83829D1C62FE89FABB.taxon	diagnosis	Diagnosis. Body shape robust or globular. Head rounded in females, with slight rostrum in males. Eyes occupying most of head surface, except for rostrum; grouped in one field on each side of head. A 1 of males with 2 - articulate peduncle; flagellum with large, crescent-shaped callynophore, with aesthetascs arranged in two-field brush medially, with distinct antero-distal lobe and small, rounded postero-distal corner over-lapping following article; with three smaller articles inserted distally. A 1 of females with 2 - articulate peduncle; callynophore narrowly rectangular, with two smaller articles inserted terminally. A 2 absent in females. A 2 of males 5 - articulate; strongly zig-zagged, with most articles folded back on each other; extending anteriorly under head and posteriorly between the gnathopods and pereopods to pereonite 7; basal article distinctly inflated, about 0.5 x or less the length of following article; following three articles of similar length; terminal article very short, not folded, pointing posteriorly. Mandibular incisor relatively broad, with several teeth, with small distal lobe medially; in males orientated more or less parallel to palp. Maxillae both absent. Maxilliped with inner lobes completely fused; medial margin of outer lobes with membranous fringe. G 1 simple. G 2 sub-chelate; carpal process knife-shaped, armed with microscopic teeth or setae. P 3 and P 4 distinctly shorter than P 5 and P 6. P 5 distinctly longer than P 6 basis slightly inflated, about 2 x as long as wide; articles 3 – 7 inserted terminally on basis. P 6 basis wider proximally in males, about 1.5 x as long as wide; articles 3 – 7 inserted terminally on basis. P 7 reduced in size with large basis; all articles present; dactylus hookshaped. U 1 with articulated rami. U 2 and U 3; endopod fused with peduncle. Rami of all uropods lanceolate, usually with serrated margins. Species. Simorhynchotus antennarius (Claus, 1871). Sexual dimorphism. Apart from the morphology of the mandibles and the antennae, females are more robust than males, especially in the pereon, as is found in Lycaea. In addition, the head of males is produced into a short, slightly pointed rostrum.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445846FF83829D1C62FE89FABB.taxon	discussion	Remarks. In the past Simorhynchotus has often been placed in the family Oxycephalidae based on the absence of maxillae (discussed earlier) and the slightly pointed head of males. However, the length of the rostrum is no greater than that found in males of the families Pronoidae or Brachyscelidae, and in general body shape, and especially in the form of G 2, Simorhynchotus resembles members of the family Lycaeidae. The pereopods, coxae and urosome are also more like Lycaeids than Oxycephalids. Thus, this genus is a link between the families Lycaeidae and Oxycephalidae. Very little is known about the biology of this genus. It has been recorded from the medusae Geryonia proboscidalis (Forsskål, 1775) (Laval 1980) and Liriope tetraphylla (Gasca et al. 2014), and Lima & Valentine (2001) recorded it in the siphonophore Sulculeolaria quadrivalvis de Blainville, 1830, although this may be an accidental inclusion. The only species of Simorhynchotus, S. antennarius is widely distributed, with a preference for near-surface, tropical waters.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445845FF9F829D1F67FBD5FE3F.taxon	description	(Figs 22 – 23)	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445845FF9F829D1F67FBD5FE3F.taxon	materials_examined	Type material. Type material of Simorhynchus antennarius could not be found in any major European institution and is considered lost. No specific type locality is given; just “ Grosses Ocean ” (the Pacific). Type material of synonyms. Type material of Simorhynchus lilljeborgi could not be found in the NRS or NHMD and is considered lost. However, the NRS has one, partly dissected, juvenile male (1632), labelled “ Guinea Cukten on Rolas R. Graeff ”, that may represent type material. No precise type locality is given; just “ tropical parts of Atlantic ”. The figures of this species provided by Bovallius (1890) confirm the synonymy. Type material of Simorhynchotus stebbingi would be the same as Stebbing’s (1888) specimen of S. antennarius because Bovallius was just proposing a new name for Stebbing’s specimen which he believed to be different from S. antennarius of Claus (1871). The type locality is the tropical Atlantic, off Africa [11 ° 05 ’ N 18 ° 15 ’ W]. Material examined. In NHMD: numerous specimens from the Dana and Thor expeditions, and others, too many to list here, from all the World’s Oceans including the Mediterranean Sea. In SAM and SAMA (part): Meiring Naude collections from S. W. Indian Ocean, off South Africa, between Kosi Bay and just S. of East London, 216 females, 111 males (88 lots), mostly 0 – 212 m, few 0 – 360 m. In SAMA: Coral Sea, Great Barrier Reef, north-east of Townsville, 9 females, 5 males (11 lots), C 12653 – 63. S. W. Pacific, Tasman Sea, off central eastern Australia [about 31 ° – 35 ° S], 4 females, 4 males (6 lots), C 5300 – 5. Bass Strait, Erith Island, 1 male, C 12651. N. E. Indian Ocean, off northern Western Australia, Ningaloo Reef and Dampier Archipelago region, numerous males (6 lots, night light trap), C 12645 – 50. S. W. Atlantic, off Brazil [24 ° 38 ’ S 45 ° 25 ’ W], 6 females, 7 males, C 12603. N. W. Pacific, off Taiwan [21 ° 01 ’ N 123 ° E], 1 male, C 12664; off Ryukyu Islands, Japan, 1 juvenile, C 12665. N. E. Pacific, off California [33 ° 02 ’ N 122 ° 03 ’ W], 1 male, C 12602. In USNM: N. W. Atlantic, from the Caribbean Sea in the south, north to Georges Bank off Massachusetts, 8 females, 8 males (12 lots), 108147, 224033, 1154666, 1154691, 1242790, 1243533, 1243537 – 43. S. W. Atlantic, off Brazil, off Sao Paulo & Rio Grande Norte, 1 female, 4 males (2 lots), 1243536, 1246988. N. E. Pacific, off Central America, 5 females, 2 males (3 lots), 108412, 1243532, 1243535. N. Pacific, near Marshall Islands, 3 males, 1243544; Hawaii, 1 male, 1243552. S. E. Pacific, off Peru [04 ° 21 ’ S 81 ° 59 ’ W], 1 female, 1243545. N. W. Pacific, Japan and Philippines region, 5 females, 20 males (7 lots), 1242803, 1243534, 1243546 – 51. Arabian Sea [27 ° 10 ’ N 49 ° 51 ’ E], 1 female, 106436.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445845FF9F829D1F67FBD5FE3F.taxon	diagnosis	Diagnosis. Body length up to 7.0 mm, but ovigerous females of about 4.0 mm have been noted. Head of females rounded, length about 0.6 x depth, as long as first 4 pereonites combined. Head of males slightly pointed, almost as long as deep, as long as first 5 pereonites combined. Buccal mass relatively small, protruding slightly below head. G 1 relatively slender, simple; basis relatively narrow, slightly longer than remaining articles combined, with slight medial bulge on anterior margin in males; carpus with few setae and slight medial bulge on posterior margin; propodus much narrower than preceding articles. G 2 marginally longer than G 1; also relatively slender except for sub-chelate carpus; basis like that of G 1; carpus almost as wide distally as propodus is long, with rounded postero-distal corner, armed with few strong setae on posterior margin. P 3 – 6 with relatively slender dactylus of moderate length, those of P 4 about 0.3 – 0.4 x propodus. P 3 and P 4 morphologically similar, P 4 slightly longer than P 3; merus slightly inflated anteriorly, sub-equal in length to carpus, slightly shorter than propodus, slightly shorter than 0.5 x basis. P 5 distinctly the longest pereopod, about 1.3 x P 4 and 1.2 x P 6; basis rectangular / oval, length 1.8 – 2.0 x maximum width, with few long setae on anterior margin; merus sub-equal in length to carpus, about 0.7 x propodus, about 0.6 x basis. P 6 basis broader than for P 5 but almost equal in length, much broader proximally in males with length 1.4 x maximum width (1.5 x in females); merus length 0.8 x propodus, about 0.5 x basis; carpus length about 0.5 x propodus; anterior margin of carpus and propodus, and sometimes also antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin, more prominent in males, length about 2.0 x maximum width in males (about 2.2 x in females), length about 0.8 x basis of P 6 for both sexes; length of remaining articles about 0.5 x basis; propodus with antero-distal corner produced into rounded lobe; dactylus sharp, hook-like. U 1 with articulated rami; exopod marginally longer than peduncle, about 0.8 x endopod. U 2 and U 3; endopod fused with peduncle; exopod slightly shorter than peduncle, about 0.5 x length endopod. Telson slightly longer than width at base, slightly more narrowed distally in males.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445845FF9F829D1F67FBD5FE3F.taxon	discussion	Remarks. Simorhynchotus antennarius is a relatively distinctive species, easily distinguished by the morphology of the gnathopods and urosome. The gelatinous associates are listed above.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
038F19445845FF9F829D1F67FBD5FE3F.taxon	distribution	Distribution. A relatively common and widespread species, found mainly in tropical regions of all the world’s oceans, including the Mediterranean Sea. It seems to prefer near-surface waters.	en	Zeidler, Wolfgang (2021): Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea). Zootaxa 5081 (1): 1-59, DOI: https://doi.org/10.11646/zootaxa.5081.1.1
