taxonID	type	description	language	source
03BF87EB051A0518B4B189ABFBB31A6E.taxon	description	(Figs. 1 – 3, 8 A, B) (?) Alpheus ochrostriatus — Karplus et al. 1981: 6, fig. 2 F (black-and-white photograph); Debelius 2001: 150 (part.?), 2 colour photographs; Randall et al. 2003: 512, fig. 8 (colour photograph); Poupin 2010: 33; Karplus & Thompson 2011: 591, fig. 4.4.10 - B (black-and-white photograph) [nomen nudum]. (?) Alpheus “ ochrostriatus ” — Anker 2000: 3, fig. 2; Jaafar & Randall 2009: 29, pl. 2 A (colour photograph); Kuiter & Debelius 2009: 151, 3 colour photographs (as Alpheus sp. ‘ ochrostriata ’) [nomen nudum]. (?) Alpheus sp. 4 — Minemizu 2013: 102, colour photograph.	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB051A0518B4B189ABFBB31A6E.taxon	materials_examined	Type material. Holotype: ov. female (cl 13.3 mm), MNHN-IU- 2013 - 16813, Papua New Guinea, Madang, sta. PR 242, 5 ° 10.2 ’ S, 145 ° 50.4 ’ E, depth 4 – 24 m, leg. A. Anker et al., 12.12.2012 [fcn PR 242 - PZD- 660 D].	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB051A0518B4B189ABFBB31A6E.taxon	description	Description. Carapace sparsely setose, not pubescent, pitted (Fig. 1 A, B). Rostrum well developed, slender, about twice as long as wide at base, subacute distally, reaching distal third of first article of antennular peduncle, somewhat descendent in lateral view; rostral carina well marked, rounded dorsally, gently sloping into shallow adrostral furrows, continuing well beyond base of orbital hoods, gradually flattening, not reaching mid-length of carapace (Fig. 1 A, B). Orbital hoods swollen, somewhat projecting anteriorly in lateral view, unarmed; frontal margin between rostrum and orbital hood shallowly concave (Fig. 1 A, B). Pterygostomial angle rounded; cardiac notch well developed, deep (Figs. 1 B, 3 B). Telson moderately broad, subrectangular, gently tapering distally, about 2.5 times as long as maximal width, with lateral margins somewhat constricted and tapering at about 0.7 times telson length; dorsal surface with two pairs of stout cuspidate setae both inserted far from lateral margin, first pair at about 0.4 telson length, second pair at about 0.7 times telson length; posterior margin broadly rounded, with row of slender spiniform setae above plumose setae; posterolateral angles each with one pair of spiniform setae, mesial ones stouter and almost three times as long as lateral ones (Fig. 1 C). Eyes well developed, with large, normally pigmented corneas (Figs. 1 A, B, 3). Antennular peduncle moderately elongate and stout; stylocerite slightly swollen laterally, distal part more slender, ending in sharp point, latter slightly overreaching distal margin of first article; ventromesial carina with large, subacute tooth; second article about 2.7 times as long as wide; lateral antennular flagellum with secondary ramus fused to main ramus over most of its length, with numerous groups of aesthetascs distally, starting from about 13 th subdivision (Fig. 1 A, B, D). Antenna with basicerite fairly stout, its distoventral margin armed with large, anteriorly projecting, sharp tooth; scaphocerite with broad blade reaching slightly beyond stout, subacute distolateral tooth, lateral margin very shallowly concave; scaphocerite reaching slightly beyond end of antennular peduncle and far beyond carpocerite (Fig. 1 A, B). Mouthparts not dissected, generally typical for genus in external observation. Third maxilliped relatively slender, elongate; coxa with bluntly projecting lateral plate; antepenultimate article flattened ventrolaterally, with distinct ridge running parallel to dorsal margin on lateral surface and rugose mesial margin, about 5.3 times as long as high; penultimate article short, cup-shaped, bulging ventrally, its distoventral margin with tuft of very long setae; ultimate article densely furnished with rows of very long, stiff setae, apical setae longest; arthrobranch well developed (Fig. 1 E). Major cheliped (female) moderately robust; ischium short, stout, smooth; merus moderately stout, somewhat elongate, trigonal in cross-section, at most four times as long as maximal width, distodorsal margin ending bluntly, ventromesial margin somewhat rugose, with weak, blunt, distal tooth, without spiniform setae; carpus short, distally widening, cup-shaped; chela not particularly elongate, fringed with long setae along dorsal and ventral surfaces; palm strongly compressed, subrectangular in cross-section, length / maximal height ratio about 1.9; surfaces relatively smooth, not markedly granulated; dorsal margin with well-marked transverse groove subdistally, without marked longitudinal ridges; ventral margin almost straight; lateral surface with distinct depression distally, near base of pollex; fingers slightly unequal in length, with dactylus shorter than pollex, about half-length of palm, not twisted or significantly deviating from chela axis; dactylus distally rounded, with plunger greatly reduced, poorly demarcated from anterior cutting edge, latter feebly bulging; adhesive disks very small (Fig. 2 A – D). Minor cheliped (female) with ischium short, smooth; merus slightly stouter than that of major cheliped, trigonal in cross-section, about 3.5 times as long as maximal width, distodorsal angle blunt, ventromesial margin slightly rugose distally, without pronounced distal tooth, armed with one spiniform seta; carpus somewhat more slender and longer than that of major cheliped, distally widening, cup-shaped; chela not elongate, not swollen, fringed with long setae along dorsal and ventral surfaces; palm compressed, subrectangular in cross-section, length / maximal height ratio about 2.0; surfaces smooth, not granulated; dorsal margin without groove; ventral margin straight; fingers slightly unequal in length, with dactylus shorter than pollex, about 1.2 times length of palm, not twisted, slightly gaping when closed, without balaeniceps crests and setae; adhesive disks greatly reduced (Fig. 2 E – G). Second pereiopod slender; ischium and merus subequal in length; carpus with five subarticles, first and second subequal, ratio of carpal subarticles approximately equal to 2.3 / 2.2 / 1.0 / 0.9 / 1.5; chela longer than distal-most carpal subarticle (Fig. 1 F). Third pereiopod moderately stout; ischium with small spiniform seta on ventrolateral surface; merus about 4.5 times as long as maximal width, ventromesial margin unarmed distally; carpus about half-length of merus, much more slender than merus, unarmed; propodus noticeably longer than carpus, moderately setose, with seven or so spiniform setae along ventral margin, including distal pair adjacent to dactylar base; dactylus about half-length of propodus, gradually curving distally, subspatulate, moderately broadened, flattened ventrally, with distinct longitudinal keel separating ventral and dorsal surfaces, latter with several tufts of setae (Fig. 1 G, H). Fourth pereiopod generally similar to third pereiopod, somewhat slenderer. Fifth pereiopod much slenderer than third and fourth pereiopods; ischium with small spiniform seta on ventrolateral surface; merus about nine times as long as wide; carpus slightly more slender than merus, about 0.9 length of merus; propodus subequal to carpus, with rows of serrulate setae forming cleaning brush on distal third of ventrolateral surface, and about 10 spiniform setae along ventromesial margin, including distal pair adjacent to dactylar base (Fig. 1 I, J). Uropod with mesial and lateral lobes of protopod each ending in sharp distal tooth; exopod broad, somewhat truncate distally, with short triangular distolateral tooth; diaeresis straight for most part, except for blunt lobe adjacent to slender spiniform seta, latter not reaching level of distal margin of exopod; endopod much narrower than exopod, with row of spiniform setae on distal margin (Fig. 1 K). Colour pattern. General background colour pale pink; carapace and pleon with broad, parallel-running, longitudinal bands each composed of narrower, ochre-red to brick-red lines and streaks, many anastomosing, forming net-like pattern; carapace flanks with broader, more diffuse and more obliquely running bands; posterior end of carapace and first pleonite with very conspicuous, transverse, white, dorsal “ saddle ”; fourth and fifth pleonites with smaller dorsal “ saddle ”; fifth pleonite with small, whitish, dorsal patch; chelipeds with yellow tinge, especially on merus and carpus, and ochre-red stripes and patches on palms and fingers; distal half of fingers hyaline-white with pinkish tinge; antennules and antennae bright yellow with ochre-orange spots and streaks, especially on antennular peduncles and scaphocerite; antennular and antennal flagella almost colourless, with yellowish or bluish tinge, respectively; second pereiopods and walking legs uniform yellow; pleopods yellowish; uropods mainly yellow with whitish areas and few ochre-orange spots on endopod; telson yellow with two ochre-red longitudinal bands flanking white mid-dorsal band (Fig. 3; see also Fig. 8 A, B).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB051A0518B4B189ABFBB31A6E.taxon	etymology	Etymology. This new species is named after the author’s friend and colleague, Dr. Andrew Thompson, an expert of ecology and evolution of goby-shrimp symbioses (Thompson 2004, 2005; Karplus & Thompson 2011).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB051A0518B4B189ABFBB31A6E.taxon	distribution	Distribution. Indo-West Pacific: so far confirmed only from Papua New Guinea (Madang); numerous photographic records (as “ A. ochrostriatus ” or Alpheus sp.) ranging from the Red Sea (Karplus et al. 1981) to Indonesia (Randall et al. 2007; Kuiter & Debelius 2009) and Japan (Anker 2000; Karplus & Thompson 2011); also recorded, possibly based on colour photographs, from New Caledonia (Poupin 2010, as “ A. ochrostriatus ”); however, all records from outside of the type locality require confirmation as more than one species might be involved (see below).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB051A0518B4B189ABFBB31A6E.taxon	biology_ecology	Ecology. Coral reefs and adjacent reef flats; associated with numerous gobies, including Amblyeleotris wheeleri (Polunin & Lubbock), and possibly also A. steinitzi (Klausewitz), A. guttata (Fowler), Ctenogobiops pomastictus Polunin & Lubbock, and C. tangaroai Lubbock & Polunin (Fig. 8 A, B; see also Karplus et al. 1981; Anker 2000; Debelius 2001; Randall et al. 2003, 2007; Kuiter & Debelius 2009; Jaafar & Randall 2009; Karplus & Thompson 2011; however, see discussion below).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB051A0518B4B189ABFBB31A6E.taxon	discussion	Remarks. Alpheus thompsoni sp. nov. has a very striking colour pattern (Figs. 3, 8 A, B), which is characterised by the long, narrow, longitudinal bands of ochre-red to brick-red colour on a generally pale-yellow body and chelipeds, sharply contrasting with the bright yellow colour of the remaining appendages (antennules, antennae, walking legs and uropods). The white “ saddle ” between the carapace and pleon, which is also present in several other goby-associated species (e. g. Karplus et al. 1981; Kuiter & Debelius 2009; Minemizu 2013) is very conspicuous. This colour pattern separates the new species from A. bellulus (see Miya & Miyake 1969; Debelius 2001; Kuiter & Debelius 2009; Minemizu 2013; see also Fig. 8 F), A. macellarius (see Anker et al. 2015; Anker & De Grave 2016), A. fenneri (see Bruce 1994; Kuiter & Debelius 2009), and A. mannarensis (see Purushothaman et al. 2021), as well as the strikingly coloured species reported as A. djiboutensis by Holthuis (1958), A. djeddensis s. lat. by Anker & De Grave (2016) and A. djeddensis by Dehghani et al. (2019). The above described colour pattern of A. thompsoni sp. nov. is identical or at least very similar to that of many snapping shrimps associated with gobies across the Indo-West Pacific. This species was sometimes identified as “ A. ochrostriatus ”, a nomen nudum first used by Karplus et al. (1981), or as “ Alpheus sp. ” Upon the author’s request, Dr. Ilan Karplus provided scans of two colour slides of a snapping shrimp identified as “ A. ochrostriatus ” from Eilat, Israel, which were taken during his ecological studies in the 1980 s. Although the photographed specimen was not deposited (or at least is untraceable), the shrimp on these slides is indeed similar to the holotype of A. thompsoni sp. nov. both in general morphology and colour pattern. This fact combined with numerous in situ colour photographs (e. g. Randall et al. 2003; Kuiter & Debelius 2009; Jaafar & Randall 2009; Karplus & Thompson 2011; Minemizu 2013) suggest that A. thompsoni sp. nov. may be distributed from the northern Red Sea to southern Japan and New Caledonia. However, the taxonomic status of the Red Sea populations originally reported as “ A. ochrostriatus ” (Karplus et al. 1981) will need to be confirmed morphologically and genetically, in view of high level of endemism of the area and differences in some colour pattern details (A. Anker, pers. obs.). Therefore, A. thompsoni sp. nov. remains known with certainty only from the type locality in Papua New Guinea, until more material is collected and analysed morphologically and genetically. More generally, the name “ A. ochrostriatus ” should not be used in the future, even if the Red Sea material is confirmed to be a distinct, undescribed species, since (1) it represents a nomen nudum (De Grave & Fransen 2011) and (2) was apparently used for at least two colour morphs (e. g. Debelius 2001; Randall 2007; see also discussion in Anker 2000). This is also true for the two other unavailable (and therefore invalid) names in Karplus et al. (1981). The second colour morph of “ A. ochrostriatus ” (shown in Fig. 8 E) could represent the recently described A. mannarensis, despite some differences in the shape and of the reddish lines on the pleon and the much less conspicuous white “ saddles ” in A. mannarensis. Using the key to the A. brevirostris group in Bruce (1994), A. thompsoni sp. nov. would key out to A. djeddensis, a species described based on three male and two female specimens from Djeddah, Saudi Arabia (Coutière 1897). However, several elements of the morphology of A. djeddensis mentioned and / or illustrated by Coutière (1897, 1899) and De Man (1909) separate A. thompsoni sp. nov. from A. djeddensis. In the new species, the scaphocerite blade exceeds the adjacent distolateral tooth (Fig. 1 A), whereas in A. djeddensis, the blade has the same length as the distolateral tooth (De Man 1909: fig. 26). In A. thompsoni sp. nov., the fingers of the female minor chela are not balaeniceps, whereas the dorsal surface of the palm is smooth, without discernable grooves. In contrast, in A. djeddensis, the minor chela fingers are strongly balaeniceps in both sexes, whereas the palm has a longitudinal groove departing from a distinct transverse groove and running parallel to the palm’s dorsal margin, as seen in the very detailed illustration of the minor chela provided by Coutière’s (1899: fig. 232, as A. rapax var. Djeddensis). Both characters were verified in the male and female syntypes of A. djeddensis (RMNH. CRUS. D. 1781), although the palmar grooves seem to be less developed in the female minor chela. However, some other distinguishing features were found during the examination of the type material of A. djeddensis. The stylocerite of A. thompsoni sp. nov. appears to be somewhat longer and less swollen than in A. djeddensis (reaching or slightly overreaching the distal margin of the antennular peduncle in the new species vs. not reaching it in A. djeddensis), whereas the antennal carpocerite is shorter (not reaching the distal margin of the scaphocerite in the new species vs. overreaching it in A. djeddensis). Their major chelae are also somewhat different, for instance, in the proportion of the fingers to the palm (0.4 in A. thompsoni sp. nov. vs. 0.6 in A. djeddensis), and in the cutting edge of the dactylus (with a less developed plunger and feebly bulging in A. thompsoni sp. nov. vs. with a more pronounced plunger and with a strong anterior bulge in A. djeddensis). It must be noted, however, that in the A. brevirostris group, the major and minor chelipeds of females are generally smaller than their male counterparts and may exhibit slightly different proportions. Alpheus thompsoni sp. nov. can be separated from A. djiboutensis, as described by De Man (1909), by the shape of the antennal scaphocerite, more precisely, by the blade reaching slightly beyond the adjacent distolateral tooth in the new species (Fig. 1 A) vs. by the distolateral tooth by far overreaching the blade in A. djiboutensis (De Man 1909: fig. 19; see also Banner & Banner 1982: fig. 55 a, m). In addition, in A. thompsoni sp. nov., the first subarticle of the second pereiopod carpus is almost as long as the second (Fig. 1 F), whereas in A. djiboutensis, the first subarticle is noticeably longer than the second (De Man 1909: fig. 23). The two species also seem to differ by the proportions of the major and minor chelae, which are much stouter in A. djiboutensis (cf. Fig. 2 and De Man 1909: 20, 21), although this character needs to be confirmed in the presence of adult male specimens in the future [same remark as above]. According to De Man (1909), the ventromesial margin of the major cheliped merus of A. djiboutensis is armed with a stout and sharp tooth, which is blunt and poorly developed in A. thompsoni sp. nov. (Fig. 2 B). An ongoing study of the goby-associated snapping shrimps of the Red Sea, largely based on material collected off the Red Sea coast of Saudi Arabia in 2012 (FLMNH UF), enabled to distinguish five morphotypes, each with a different, highly diagnostic colour pattern. One of them corresponds to “ A. ochrostriatus ” (nomen nudum) of Karplus et al. (1981), as mentioned above, and may or may not be the same as A. thompsoni sp. nov. (Anker, in prep.). The second is a very distinctive morphotype with a unique colour pattern type, reported as “ A. rubromaculatus ” (nomen nudum) by Karplus et al. (1981); this clearly new species will be described elsewhere (Anker, in prep.). The remaining three morphotypes are morphologically in line with A. djeddensis and A. djiboutensis, although one of them represents yet another, possibly undescribed species (Anker, in prep.). Although the latter three taxa are still being evaluated taxonomically, their colour patterns are very different from that of A. thompsoni sp. nov., which strengthens its separation from A. djeddensis and A. djiboutensis. As mentioned above, A. thompsoni sp. nov. can be easily separated from A. bellulus, A. macellarius, A. fenneri and A. mannarensis by its diagnostic colour pattern and also, from each of them, by at least two morphological characters. For instance, A. thompsoni sp. nov. differs from A. bellulus by the rostrum much narrower and longer (vs. shorter and subtriangular in A. bellulus), and by the different proportions of the female major and minor chelipeds, especially by the more slender meri, the more slender major and minor chelae, and the minor chela fingers subequal in length to the palm and non-balaeniceps (vs. with the minor chela fingers longer than the palm and sub-balaeniceps in A. bellulus, see Miya & Miyake 1969: fig. 2 E, F). The new species can be morphologically separated from A. macellarius by the lateral margin of the antennal scaphocerite almost straight (vs. strongly concave in A. macellarius), the ventromesial margin of the chelipeds distally unarmed (vs. armed with a sharp tooth in A. macellarius), the much stouter minor chela (which is very slender in A. macellarius), and the second pereiopod carpus with the two first subarticles subequal in length (vs. with the first subarticle much longer than the second in A. macellarius) (see Chace 1988: fig. 6 a, e, f, h). Furthermore, A. thompsoni sp. nov. differs from A. fenneri by the scaphocerite blade reaching far beyond the adjacent distolateral tooth (vs. not or barely reaching the distolateral tooth in A. fenneri), the mesial surface of the major and minor chelae not granulated (vs. distinctly granulated in A. fenneri), and the relatively shorter and more slender penultimate article of the third maxilliped (which is very stout in A. fenneri) (see Bruce 1994: figs. 1 C, 2 A – D). Finally, A. thompsoni sp. nov. differs from A. mannarensis by the second pereiopod carpus with the two first subarticles subequal in length (vs. with the second subarticle distinctly longer than the first in A. mannarensis), the mesial surface of the major and minor chelae not granulated (vs. faintly granulated in A. mannarensis), and the longer stylocerite, reaching the distal margin of the first article of the antennular peduncle (vs. not reaching it in A. mannarensis) (see Purushothaman et al. 2021: figs. 2 B, 3 B, D, G).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB05130510B4B18CFFFCF31956.taxon	description	(Figs. 4 – 7, 8 C)	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB05130510B4B18CFFFCF31956.taxon	materials_examined	Type material. Holotype: male (cl 8.6 mm), MNHN-IU- 2018 - 5667, Solomon Islands, New Georgia, Munda, Hopei Island, shallow sand flat, suction (yabby) pump, depth 0.5 – 1 m, leg. A. Anker, 14.09.2016 [fcn SOL- 106]. Paratypes: 1 male (cl 9.3 mm), MNHN-IU- 2018 - 5669, Solomon Islands, New Georgia, Munda, Sosuhite Island, shallow sand flat with coral rubble, depth 0.5 – 2 m, in burrow under large piece of coral rubble, leg. A. Anker, 19.09.2016 [fcn SOL- 047]; 1 ov. female (cl 10.7 mm), MNHN-IU- 2018 - 5668, Australia, Queensland, Heron Island, southern side, shallow reef flat, coarse sand, suction (yabby) pump, 0.5 – 1 m, leg. A. Anker, 28.09.2016 [fcn HE- 011]; 1 male (cl 6.6 mm), 1 female (cl 8.4 mm), MNHN-IU- 2018 - 5670, Australia, Queensland, Heron Island, southern side, shallow reef flat, coarse sand, suction (yabby) pump, 0 – 0.5 m, leg. A. Anker, 24.09.2016 [fcn HE- 120]; 1 male (cl 16.0 mm, missing both chelipeds), MNHN-IU- 2018 - 5525, Australia, Queensland, Heron Island, southern side, shallow reef flat, coarse sand, suction (yabby) pump, 0 – 0.5 m, leg. A. Anker, 25.09.2016 [fcn HE- 026]. Additional material. 1 male (cl 14.5 mm), MNHN-IU- 2018 - 5671, Vietnam, Nha Trang Bay, Tre Island, Tre Bay, intertidal area near mangrove, suction (yabby) pump, with goby, leg. I. N. Marin, 12.07.2006.	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB05130510B4B18CFFFCF31956.taxon	description	Description. Carapace not setose, not pubescent, pitted (Fig. 4 A, B). Rostrum well developed, wide, about 1.7 times as long as wide at base, subacute distally, just reaching distal third of first article of antennular peduncle, pointing straight-forward in lateral view; rostral carina well marked, rounded dorsally, gently sloping into welldemarcated adrostral furrows, continuing well beyond base of orbital hoods, gradually flattening, not reaching midlength of carapace (Fig. 4 A, B). Orbital hoods swollen, feebly projecting anteriorly in lateral view, unarmed; frontal margin between rostrum and orbital hood shallowly concave (Fig. 4 A, B). Pterygostomial angle rounded; cardiac notch well developed, deep (Figs. 4 B, 7 B). Telson very broad, subrectangular, gently tapering distally, about 1.8 times as long as maximal width, with lateral margins not noticeably constricted; dorsal surface with two pairs of stout cuspidate setae both inserted far from lateral margin, first pair at about 0.5 telson length, second pair at about 0.7 of telson length; posterior margin broadly rounded, with row of short spiniform setae above plumose setae (less conspicuous or with slender spiniform setae in some specimens); posterolateral angles each with one pair of spiniform setae (typically, sometimes with only one spiniform seta), mesial ones stouter and two to three times as long as lateral ones [posterolateral spiniform setae somewhat aberrant in the illustrated paratype (Fig. 4 C), see Fig. 6 C for more typical condition]. Eyes well developed, with large, normally pigmented corneas (Figs. 1 A, B, 7). Antennular peduncle moderately elongate and stout; stylocerite feebly swollen laterally, distal part slenderer, ending in sharp point, latter not reaching distal margin of first article; ventromesial carina with large subtriangular tooth; second article about 2.7 times as long as wide; lateral antennular flagellum with secondary ramus fused to main ramus over most of its length, with numerous groups of aesthetascs distally, starting from about 14 th subdivision (Fig. 4 A, B, D). Antenna with basicerite fairly stout, its distoventral margin armed with large, anteriorly projecting, sharp tooth; scaphocerite with moderately broad blade distinctly exceeded by sharp distolateral tooth, lateral margin shallowly concave; scaphocerite reaching distinctly beyond end of antennular peduncle and slightly beyond carpocerite (Fig. 4 A, B). Mouthparts not dissected, generally typical for genus in external observation. Third maxilliped relatively stout; coxa with bluntly projecting lateral plate; antepenultimate article flattened ventrolaterally, with distinct ridge running parallel to dorsal margin on lateral surface and rugose mesial margin, about 3.9 times as long as high; penultimate article very short, cup-shaped, bulging ventrally, its distoventral margin with few moderately long setae, its dorsal margin with row of elongate setae; ultimate article densely furnished with rows of very long, stiff setae, dorsal and apical setae longest; arthrobranch well developed (Fig. 4 E). Male major cheliped robust; ischium short, stout, smooth; merus very stout, trigonal in cross-section, about twice as long as maximal width, distodorsal margin ending bluntly, ventromesial margin somewhat rugose, with more or less pronounced, blunt, distal tooth and row of five or six spiniform setae; carpus short, distally widening, cup-shaped; chela not particularly elongate, fringed with long setae along dorsal and ventral surfaces; palm strongly compressed, stout, subrectangular in cross-section, length / maximal height ratio 1.8 – 2.1 (lower in larger males); surfaces relatively smooth, without granules; dorsal margin with well-marked transverse groove subdistally, without marked longitudinal ridges; ventral margin almost straight; lateral surface with shallow depression distally, near base of pollex; fingers subequal in length, about half-length of palm, not twisted or significantly deviating from chela axis; dactylus distally rounded, plunger somewhat reduced, poorly demarcated from anterior cutting edge, latter slightly bulging; adhesive disks very small (Fig. 5 A – D; see also Fig. 6 A). Female major cheliped generally similar to male major cheliped, smaller, weaker; chela with somewhat different proportions (see Fig. 7 C). Male minor cheliped with ischium short, smooth; merus similar to that of major cheliped in size and stoutness, trigonal in cross-section, distodorsal angle blunt, ventromesial margin slightly rugose distally, usually without distal tooth, armed with spiniform setae; carpus distinctly longer than that of major cheliped, distally widening, cupshaped; chela not elongate, not swollen, fringed with long setae along dorsal and ventral surfaces; palm compressed, subrectangular in cross-section, length / maximal height ratio 1.3 – 1.5 (lower in larger males); surfaces smooth, not granulated; dorsal margin without groove; ventral margin broadly convex; fingers subequal in length, about 1.3 times length of palm, not twisted, slightly gaping when closed, with balaeniceps crests lined with setae (better developed in larger males); adhesive disks greatly reduced (Fig. 5 E, F; see also Fig. 6 B). Female minor cheliped generally similar, but with weaker chela, latter with balaeniceps ridges and setae on fingers poorly developed or lacking (Fig. 7 C). Second pereiopod slender; ischium and merus subequal in length; carpus with five subarticles, first noticeably longer than second, ratio of carpal subarticles approximately equal to 3.0 / 2.5 / 1.0 / 1.0 / 1.7; chela longer than distalmost carpal subarticle (Fig. 4 F). Third pereiopod fairly robust; ischium with stout spiniform seta on ventrolateral surface; merus about 4.1 times as long as maximal width, ventromesial margin unarmed distally; carpus about 0.6 length of merus, much more slender than merus, unarmed; propodus subequal to carpus, setose, with at least 10 spiniform setae along ventral margin, including distal pair adjacent to dactylar base; dactylus slightly more than halflength of propodus, gradually curving distally, subspatulate, moderately broadened, flattened ventrally, with distinct longitudinal keel separating ventral and dorsal surfaces, with scarce setae (Fig. 4 G). Fourth pereiopod generally similar to third pereiopod, more slender. Fifth pereiopod much more slender than third and fourth pereiopods; ischium with small spiniform seta on ventrolateral surface; merus about 5.7 times as long as wide; carpus slightly more slender than merus, about 0.9 length of merus; propodus subequal to carpus, with rows of serrulate setae forming cleaning brush on distal third of ventrolateral surface, and at least eight spiniform setae along ventromesial margin, including distal pair adjacent to dactylar base (Fig. 4 H, I). Second pleopod with appendices masculina and interna equal in length, former with long stiff setae (Fig. 4 J). Uropod with mesial and lateral lobes of protopod each ending in sharp (lateral) or blunt (mesial) distal tooth; exopod broad, broadly rounded distally, with short triangular distolateral tooth; diaeresis straight for most part, except for rounded lobe adjacent to slender spiniform seta, latter not reaching level of distal margin of exopod; endopod much narrower than exopod, with row of spiniform setae on distal margin (Fig. 4 K). Colour pattern. General background colour white with pale yellowish tinge; carapace with several (three to four) broad bands, running transversely dorsally and more obliquely laterally, some broadly croissant-shaped; carapace flanks with very large brown to almost black spot (quickly fading in captured individuals); pleon with narrower, transversely-obliquely running, brown bands, usually two per pleonite; posterior end of carapace and first pleonite with conspicuous, white, dorsal “ saddle ”; fourth and fifth pleonites with transverse, whitish, dorsal patches; chelipeds whitish or greyish, with irregular, brown, green-brown or green-bluish patches; distal half of fingers hyaline-white; antennules and antennae whitish with brownish spots and streaks; antennular flagella pale yellow proximally, more intense yellow distally; antennal flagella pale yellow proximally, uncoloured distally; second pereiopods and walking legs greyish-blue with yellow markings around articulations; pleopods brownish yellow; uropods whitish with some brown-red bands or spots, mainly on endopod; telson yellow whitish proximally, with brown-red pattern distally (Figs. 7, 8 C; see also Anker & De Grave 2019: fig. 4 C).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB05130510B4B18CFFFCF31956.taxon	etymology	Etymology. This new species is named after Justin Scioli, PhD cand., the author’s great friend and collaborator in projects involving taxonomy and phylogenetics of alpheid shrimps.	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB05130510B4B18CFFFCF31956.taxon	distribution	Distribution. Western Pacific: confirmed records from Solomon Islands, Australia (Great Barrier Reef) and Vietnam (present study); photographic records from the Philippines (Palawan), Indonesia (Java, Flores, Bali), Papua New Guinea and Palau (Debelius 2001; Randall et al. 2007; Kuiter & Debelius 2009; Hurt et al. 2021).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB05130510B4B18CFFFCF31956.taxon	biology_ecology	Ecology. Shallow coral reefs and adjacent reef flats and lagoons; associated with gobies, typically Cryptocentrus cinctus (Herre), C. fasciatus (Playfair), C. leptocephalus Bleeker and C. inexplicatus (Herre), but also Ctenogobiops pomastictus (Fig. 8 C; see also Debelius 2001; Randall et al. 2007; Kuiter & Debelius 2009; Hurt et al. 2021); may also harbour the “ commensal ” palaemonid shrimp, Palaemonella aliska Marin, 2008 (Marin 2008; Anker & De Grave 2019).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
03BF87EB05130510B4B18CFFFCF31956.taxon	discussion	Remarks. Alpheus sciolii sp. nov. has a unique and unmistakable colour pattern (Figs. 7, 8 C), characterised by the dark-brown or olive-brown transverse banding and the presence of a very large dark spot on the flanks of the carapace. As in the previous species, the white “ saddle ” marking the limit between the carapace and the pleon is quite conspicuous. This colour pattern (Fig. 7; see also Kuiter & Debelius 2009, as Alpheus sp. 6, and Minemizu 2013, as Alpheus sp. 2) is very different from the colour patterns of A. bellulus, A. macellarius, A. fenneri, A. mannarensis (see Miya & Miyake 1969; Debelius 2001; Kuiter & Debelius 2009; Minemizu 2013; Anker et al. 2015; Purushothaman et al. 2021; for A. bellulus see also Fig. 8 F) and A. thompsoni sp. nov. (Figs. 3, 8 A, B). The non-type male specimen of A. sciolii sp. nov. from Nha Trang, Vietnam, has noticeably larger and stouter chelipeds, with a markedly stronger balaeniceps condition on the minor chela fingers, compared to that of the complete male type specimens from the Solomon Islands and Australia, (Fig. 6 A, B), which may be simply due to its larger size (cl 14.5 mm vs. 6.6 – 9.3 mm). A large paratype male of similar size (cl 16.0 mm) from Heron Island is unfortunately lacking both of its chelipeds (see Anker & De Grave 2019: fig. 4 C). The Nha Trang specimen also seems to have a darker colour (see Marin 2008: fig. 9 b), although it is partly covered by detritus and sediment. In addition, a colour pattern very similar to that of A. sciolii exists in shrimps associated with different gobies, such as Amblyeleotris steinitzi (Klausewitz) (see Fig. 8 D). Therefore, collection of additional material and a molecular comparison between the specimens of A. sciolii sp. nov. from Solomon Islands / Australia and Vietnam (or other parts of South-East Asia) are highly desirable. The separation of A. sciolii sp. nov. from A. djeddensis is based on the same criteria as those used by De Man (1909) to distinguish A. djiboutensis from A. djeddensis, viz. the scaphocerite blade reaching well beyond the adjacent distolateral tooth in both A. sciolii sp. nov. and A. djiboutensis (vs. not reaching beyond it in A. djeddensis), and the first subarticle of the second pereiopod carpus noticeably longer than the second in A. sciolii sp. nov. and A. djiboutensis (vs. as long as the second in A. djeddensis). On the other hand, A. sciolii sp. nov. may be separated from A. djiboutensis by the much broader telson, which is around 1.8 times as long as maximal width in A. sciolii sp. nov. (Figs. 4 C, 6 C) vs. 2.1 times in A. djiboutensis (see De Man 1909: fig. 18). In fact, the telson of A. sciolii sp. nov. appears to be the broadest among the presently known species of the A. djeddensis – A. djiboutensis complex. Also noteworthy is that no snapping shrimp with the colour pattern of A. sciolii sp. nov. is known from the Red Sea (Karplus et al. 1981) or western Indian Ocean (Polunin & Lubbock 1977), from where A. djeddensis and A. djiboutensis were origially described. The Australian material reported as A. djiboutensis by Banner & Banner (1982) appears to contain more than one species (possibly including the true A. djiboutensis and A. sciolii sp. nov.) and will need to be carefully re-examined. Alpheus sciolii sp. nov. can be distinguished morphologically from A. bellulus by the rostrum much narrower and longer (vs. shorter and subtriangular in A. bellulus), the ventral margin of the major chela almost straight to slightly convex (vs. somewhat concave in A. bellulus), and the telson 1.8 times as long as broad (vs. 2.5 times as long as broad) (see Miya & Miyake 1969: figs. 1, 2 B, C); from A. macellarius by the distolateral tooth of the antennal scaphocerite pointing straight-forward (vs. curved mesially in A. macellarius), the much stouter minor chela (which is very slender in A. macellarius), and the much stouter third pereiopod merus, about four times as long as wide (vs. almost six times in A. macellarius) (see Chace 1988: fig. 6 e, f, i); from A. fenneri by the distolateral tooth of the scaphocerite reaching far beyond the blade (vs. not or very slightly overreaching the blade in A. fenneri), the mesial surface of the major and minor chelae not granulated (vs. distinctly granulated in A. fenneri), and the posterior margin of the telson unarmed between the mesial pair of the posterolateral spiniform setae (vs. with a row of spiniform setae in A. fenneri) (see Bruce 1994: figs. 1 C, M, N, 2 C); from A. mannarensis by the distolateral tooth of the scaphocerite reaching far beyond the blade (vs. not reaching the anterior margin of the blade in A. mannarensis), the second pereiopod carpus with the first subarticle slightly longer than the second (vs. with the second subarticle noticeably longer than the first in A. mannarensis), the posterior margin of the telson unarmed between the mesial pair of the posterolateral spiniform setae (vs. with a row of spiniform setae in A. mannarensis) (see Purushothaman et al. 2021: figs. 2 B, E, 3 G); and from the above-described A. thompsoni sp. nov. by the relative development of the distolateral tooth of the scaphocerite (cf. Figs. 1 A, 4 A), the length-width proportions of the telson (cf. Figs. 1 C, 4 C), the much stouter third maxilliped, without extremely elongate setae on the pendultimate article (cf. Figs. 1 E, 4 E), and the much stouter walking legs (cf. Figs. 1 G, I, 4 G, H).	en	Anker, Arthur (2022): Description of two new species of goby-associated snapping shrimps from the tropical western Pacific (Decapoda: Alpheidae: Alpheus). Zootaxa 5092 (3): 273-290, DOI: https://doi.org/10.11646/zootaxa.5092.3.2
