taxonID	type	description	language	source
03815953FFB22E1A142B7932FD8B1ED9.taxon	discussion	The type species for the family Gorgocephalidae, Gorgocephalus kyphosi, was described based on five specimens from Kyphosus sydneyanus collected from near Port Noarlunga, South Australia (Manter, 1966). The species has also been reported from K. vaigiensis from Lizard Island, GBR, Australia and from Moorea, Society Islands, French Polynesia (Bray, 2005 b; Bray & Cribb, 2005). Molecular sequences have been provided previously for a specimen identified as G. kyphosi (Olson et al., 2003), although this specimen was collected from K. vaigiensis from off Lizard Island, GBR, rather than from the type host and locality. Port Noarlunga is now a protected marine reserve and the closest locality from which we were able to capture specimens of K. sydneyanus was Point Riley, Yorke Peninsula, South Australia. This locality is approximately 160 km from Port Noarlunga. However, we examined the holotype (borrowed from the Smithsonian National Museum of Natural History, USA; USNM 1356481) and found that the morphology of this specimen was consistent with those from Point Riley; thus, we consider our specimens from South Australia to be conspecific with G. kyphosi.	en	Huston, Daniel C., Cutmore, Scott C., Miller, Terrence L., Sasal, Pierre, Smit, Nico J., Cribb, Thomas H. (2021): Gorgocephalidae (Digenea: Lepocreadioidea) in the Indo-West Pacific: new species, life-cycle data and perspectives on species delineation over geographic range. Zoological Journal of the Linnean Society 193 (4): 1416-1455, DOI: 10.1093/zoolinnean/zlab002, URL: https://doi.org/10.1093/zoolinnean/zlab002
03815953FFB22E1A142B7932FD8B1ED9.taxon	description	We obtained adults corresponding to the ‘ Gorgocephalus kyphosi ’ morphotype from all collection localities where gorgocephalids were found, except for Kioloa, NSW, Australia where only gastropods were collected. Based on the measurements and morphological description of G. kyphosi provided by Manter (1966), all of these adult specimens could be diagnosed as that species. However, molecular data indicated that up to six species could be distinguished under the umbrella of this morphological concept. Reassessment of morphology in light of molecular data, on a clade-by-clade basis, allowed separation of G. euryaleae and G. graboides from G. kyphosi, largely on the proportion of the cirrus-sac occupied by the internal seminal vesicle, pars prostatica and ejaculatory duct (see Taxonomy section). Both new species correspond to well-supported clades in all analyses (Figs 3 – 6). Recognition of these two species allows refinement of our morphological and molecular profile for G. kyphosi. After exclusion of the two new species, sequences representative of the refined concept of Gorgocephalus kyphosi formed a large clade in all analyses (Figs 3 – 6), although there was relatively poor bootstrap support (65) for the clade in ML analysis of the COI dataset. This major clade was subdivided into several smaller clades, largely corresponding to collection locality. Sequences of the ITS 2 and 28 S rDNA gene regions for G. kyphosi were fairly conserved, differing by no more than 3 bp (<1 %) within or between localities (Table 5). Phylogenetic analyses of the ITS 2 and 28 S datasets demonstrated that sequences generated from specimens from two Australian localities (Moreton Bay and South Australia) were more similar to those from French Polynesia than to those from the third Australian locality (Lizard Island, GBR). Although sequences of the COI mtDNA gene region differed by no more than 6 bp (~ 1.3 %) within each locality, large differences up to 62 bp (~ 13 %) occurred between localities (Table 5). As with the ITS 2 and 28 S data, COI sequences generated from specimens from Moreton Bay and South Australia were more similar to each other and to those from French Polynesia (~ 1 – 6 % difference) than to those from Lizard Island, GBR (~ 12 – 13 % difference; Supporting Information, Table S 5). These molecular differences, coupled with this geographic pattern, possibly indicate a species-level distinction. However, no significant morphological differences were observed between any specimens from the above named localities, and there are no host differences. Furthermore, in all phylogenetic analyses the Lizard Island clade was sister to the remaining putative sequences of G. kyphosi from other IWP localities. Thus, we conservatively consider all of these specimens as representative of G. kyphosi. Sequences of G. kyphosi differ from the other species of the Gorgocephalidae investigated here by 65 – 88 bp (14 – 15 %), 4 – 18 bp (0.9 – 4.0 %) and 5 – 20 bp (0.5 – 2.0 %) in the COI, ITS 2 and 28 S gene regions, respectively (Table 5). Two intermediate hosts were identified for this species using COI, ITS 2 and 28 S sequences (Figs 3 – 6). Six Bembicium auratum, collected from near Dunwich, North Stradbroke Island, Moreton Bay, Australia, were found infected with gorgocephalids. Three infections were matched to adult worms obtained from Kyphosus cinerascens collected nearby, from off Amity Point, North Stradbroke Island. In addition, a single infected Echinolittorina vidua, collected from Lizard Island, GBR, was matched to adults obtained from K. vaigiensis collected from off the same locality using ITS 2 gene sequences. Gorgocephalus euryaleae and Gorgocephalus graboides These two new species are morphologically differentiated from Gorgocephalus kyphosi, and each other, largely on features within the cirrus-sac (see Taxonomy section). Sequences for these species form well-supported clades in all analyses (Figs 3 – 6), with presumed conspecifics collected from the same locality differing by no more than 3 bp in any of the three sequenced gene regions (Table 5). Sequences of G. euryaleae differ by 10 – 11 bp (~ 2 %), 1 bp (~ 0.2 %) and 1 – 2 bp (0.1 – 0.2 %) in the COI, ITS 2 and 28 S gene regions, respectively, between Western Australia and South Africa. Sequences of G. euryaleae differ from the others species of the Gorgocephalidae recognized here by 66 – 87 bp (14 – 18 %), 4 – 19 bp (0.9 – 4.2 %) and 5 – 23 bp (0.5 – 2.3 %) in the COI, ITS 2 and 28 S gene regions, respectively. Sequences of G. graboides, found at only one locality, differ from other gorgocephalid species by 65 – 81 bp (14 – 17 %), 14 – 19 bp (3.1 – 4.2 %) and 18 – 23 bp (1.8 – 2.3 %) in the COI, ITS 2 and 28 S gene regions, respectively (Table 5). Gorgocephalus graboides was recovered only from Kyphosus cinerascens collected from off Lizard Island, GBR, whereas G. euryaleae was recovered from K. cinerascens in South Africa and from K. gladius and K. sydneyanus from Western Australia. Although the two new species are apparently geographically isolated from one another, they share at least one definitive host. Both species also have an overlapping definitive host range with G. kyphosi (K. sydneyanus and K. cinerascens for G. euryaleae and K. cinerascens for G. graboides). Furthermore, intramolluscan gorgocephalids from a single infected Echinolittorina vidua from Lizard Island were successfully matched to G. graboides. Thus, G. graboides also shares an intermediate host with G. kyphosi.	en	Huston, Daniel C., Cutmore, Scott C., Miller, Terrence L., Sasal, Pierre, Smit, Nico J., Cribb, Thomas H. (2021): Gorgocephalidae (Digenea: Lepocreadioidea) in the Indo-West Pacific: new species, life-cycle data and perspectives on species delineation over geographic range. Zoological Journal of the Linnean Society 193 (4): 1416-1455, DOI: 10.1093/zoolinnean/zlab002, URL: https://doi.org/10.1093/zoolinnean/zlab002
03815953FFBF2E0317817E01FD621EE6.taxon	discussion	This species was described by Bray & Cribb (2005) based on adult specimens obtained from Kyphosus vaigiensis, collected from off Lizard Island, GBR, Australia. Gorgocephalus yaaji is easily distinguished from all other species of the family, largely in having a more robust, dorsoventrally flattened body shape and in having the vitellarium extend into the forebody. Previously, Huston et al. (2016) generated ITS 2 and 28 S rDNA gene sequences from adult and intramolluscan specimens of G. yaaji from the type locality. In the present study, additional adult gorgocephalids morphologically consistent with G. yaaji were obtained from the type locality and from Rangiroa Atoll in French Polynesia and Sodwana Bay in South Africa (Fig. 1). Despite extensive investigation, including traditional morphometrics, PCA analyses and SEM imaging, we were unable to find any significant morphological differences between specimens from these three localities. Intramolluscan gorgocephalids from three Echinolittorina cinerea collected from Rangiroa Atoll, French Polynesia were molecularly matched to adults consistent with G. yaaji collected from the same locality. Furthermore, intramolluscan gorgocephalids have previously been collected from Austrolittorina unifasciata, from multiple locations along the coast of New South Wales, Australia (O’Dwyer et al., 2015; Huston et al., 2016), but they had not previously been connected to an adult form. BLAST analyses showed that the sequences generated from intramolluscan gorgocephalids collected from Kioloa, NSW, matched sequences of ‘ Gorgocephalus sp. Aus’ from the study of O’Dwyer et al. (2015) with identity scores of 98 – 100 %, demonstrating that gorgocephalids collected from A. unifasciata in the studies of O’Dwyer et al. (2015) and Huston et al. (2016) are conspecific. The present phylogenetic analyses (Figs 3 – 6) demonstrate that these infections are representative of G. yaaji.	en	Huston, Daniel C., Cutmore, Scott C., Miller, Terrence L., Sasal, Pierre, Smit, Nico J., Cribb, Thomas H. (2021): Gorgocephalidae (Digenea: Lepocreadioidea) in the Indo-West Pacific: new species, life-cycle data and perspectives on species delineation over geographic range. Zoological Journal of the Linnean Society 193 (4): 1416-1455, DOI: 10.1093/zoolinnean/zlab002, URL: https://doi.org/10.1093/zoolinnean/zlab002
03815953FFBF2E0317817E01FD621EE6.taxon	description	Despite adult gorgocephalids consistent with Gorgocephalus yaaji collected from across the IWP being morphologically indistinguishable, phylogenetic analyses of the ITS 2 and 28 S rDNA single-gene datasets did not recover a monophyletic G. yaaji clade (Figs 4, 5). In the ITS 2 single-gene tree (Fig. 4), specimens morphologically consistent with G. yaaji were paraphyletic and formed three well-supported clades: specimens from Lizard Island (adults and intramolluscan stages), specimens from French Polynesia (adults and intramolluscan stages) + those from Kioloa, NSW, Australia (intramolluscan stages only), and those from South Africa (adults only). The first two of these clades were recovered in polytomy with the third + G. euryaleae + G. kyphosi, with G. graboides sister to all of these clades together. All ITS 2 sequences for G. yaaji were identical for specimens within each locality and differed by 0 – 5 bp (0.0 – 1.1 %) between localities (Table 5). In the 28 S rDNA single-gene tree (Fig. 5), G. yaaji was also recovered as paraphyletic, but with the South African representatives resolving as basal to all clades. The 28 S rDNA sequences of G. yaaji differed by 0 – 6 bp (0.0 – 0.6 %) between localities. In contrast to analyses of ITS 2 and 28 S rDNA, those for the COI mtDNA single-gene dataset (Fig. 3) resolved all specimens morphologically consistent with Gorgocephalus yaaji as a monophyletic group, sister to the remaining lineages of the Gorgocephalidae, albeit without support in ML analysis. Sequences differed by only 0 – 3 bp (0.0 – 0.6 %) within individual localities but differed by 12 – 62 bp (~ 3.0 – 13 %) between localities. The largest difference (62 bp) was between specimens from French Polynesia and South Africa, representing opposite sides of the IWP marine region, although the South African specimens were also relatively divergent from those collected in Australia (50 – 58 bp or ~ 11 – 12 %; Supporting Information, Table S 5). The concatenated COI + ITS 2 + 28 S analyses (Fig. 6) also resolved representatives of G. yaaji in a monophyletic clade, with lower BI posterior probability support but higher ML bootstrap support. Similar to the pattern observed for Gorgocephalus kyphosi, COI and ITS 2 sequences of G. yaaji, generated from one Australian locality (Kioloa, NSW) were more similar to those from French Polynesia than to those from another Australian locality, Lizard Island, GBR (Supporting Information, Table S 5). Such molecular variation coupled with the lack of monophyly in the ITS 2 and 28 S rDNA trees suggests the possibility of multiple species. However, in the ITS 2 and 28 S trees, sequences associated with specimens morphologically indistinguishable from G. yaaji, result in a paraphyletic, rather than a polyphyletic, G. yaaji (i. e. sequences are more, or at least, as related to one another as they are to other species represented). There are also no hostlevel distinctions to delineate additional species within the G. yaaji concept; the species appears to have a broad definitive and intermediate host range (within the confines of the Kyphosidae and Littorinidae). The issues with paraphyly in the ITS 2 and 28 S trees might be alleviated with sequences from additional specimens collected from localities between Australia and South Africa. However, without further evidence there appears no justification for splitting the G. yaaji clade into multiple morphologically cryptic species. Sequences of G. yaaji differ from the others species of the Gorgocephalidae recognized here by 66 – 88 bp (14 – 19 %), 5 – 16 bp (1.1 – 3.5 %) and 12 – 21 bp (1.2 – 2.1 %) in the COI, ITS 2 and 28 S gene regions, respectively.	en	Huston, Daniel C., Cutmore, Scott C., Miller, Terrence L., Sasal, Pierre, Smit, Nico J., Cribb, Thomas H. (2021): Gorgocephalidae (Digenea: Lepocreadioidea) in the Indo-West Pacific: new species, life-cycle data and perspectives on species delineation over geographic range. Zoological Journal of the Linnean Society 193 (4): 1416-1455, DOI: 10.1093/zoolinnean/zlab002, URL: https://doi.org/10.1093/zoolinnean/zlab002
03815953FFA62E0514907B8FFBC31994.taxon	description	(FIGS 7 – 9; TABLES 2, 6) Type host and locality: Kyphosus sydneyanus (Günther, 1886) (Perciformes: Kyphosidae), silver drummer, from near Port Noarlunga, South Australia (35 ° 09 ’ 10 ’’ S, 138 ° 27 ’ 49 ’’ E). Records: 1, Manter (1966); 2, Olson et al. (2003); 3, Bray (2005 b). 4, Bray & Cribb (2005); 5, present study. Definitive hosts: Perciformes, Kyphosidae. Kyphosus cinerascens (Forsskål, 1775), highfin chub (5); Kyphosus elegans (W. K. H. Peters, 1869), Cortez sea chub (5); Kyphosus sydneyanus (Günther, 1886), silver drummer (1, 5). Kyphosus vaigiensis (Quoy & Gaimard, 1825), brassy chub (2, 3, 4, 5). The number in brackets refer to the ‘ records’ section directly preceding this - essentially a way to avoid having to list citations repeatedly. Intermediate hosts: Gastropoda, Littorinimorpha, Littorinidae. Bembicium auratum (Quoy & Gaimard, 1834) (5); Echinolittorina vidua (Gould, 1859) (5). Other localities: Off Point Riley, Yorke Peninsula, South Australia (33 ° 52 ’ 49 ’’ S, 137 ° 35 ’ 52 ’’ E) (PR) (5); off Amity Point, North Stradbroke Island, Moreton Bay, Queensland, Australia (27 ° 23 ’ 53 ’’ S, 153 ° 26 ’ 15 ’’ E) (AP) (5); off Dunwich, North Stradbroke Island, Moreton Bay, Queensland, Australia (27 ° 29 ’ 46 ’’ S, 153 ° 23 ’ 52 ’’ E) (DW) (5); off Lizard Island, Great Barrier Reef, Queensland, Australia (14 ° 41 ’ 10 ’’ S, 145 ° 28 ’ 15 ’’ E) (LI) (2, 3, 4, 5); off Moorea, Society Islands, French Polynesia (17 ° 32 ’ 46 ’’ S, 149 ° 49 ’ 47 ’’ E) (4); off Rangiroa, Tuamotu Islands, French Polynesia (15 ° 10 ’ 40 ’’ S, 147 ° 39 ’ 04 ’’ W) (RA) (5). The letters in brackets are an abbreviation for the locality. Voucher material (adult): Ten whole-mount and three hologenophore specimens, ex K. sydneyanus from PR (SAM AHC 36801 – 36806); ten wholemount and three hologenophore specimens ex K. cinerascens from AP (QM G 238552 – G 238564); two whole-mount specimens ex K. cinerascens from LI (QM G 238571 – G 238572); 13 whole-mount and three hologenophore specimens ex K. vaigiensis from LI (QM G 238573 – G 238588); nine whole-mount and three hologenophore specimens ex K. cinerascens from RA (MNHN HEL 1431 – 1442); one whole-mount and three hologenophore specimens ex K. elegans from RA (MNHN HEL 1433 – 1446). Voucher material (intramolluscan): Six slides of rediae and cercariae ex B. auratum from DW (QM G 238565 – G 238570); three slides of rediae and cercariae ex E. vidua from LI (QM G 238589 – G 238591). Site in host: Pyloric caeca (definitive); gonad / digestive gland (intermediate). Representative DNA sequences: Twenty-one sequences deposited for COI mtDNA (MW 353629 – MW 353649); 21 sequences deposited for 5.8 S-ITS 2 - partial 28 S rDNA (MW 353910 – MW 353930); 12 sequences deposited for partial 28 S rDNA (MW 353877 – MW 353888); see Supporting Information, Table S 2. Description of adult (Figs 7 A, B, E, 8, 9 A – C): Measurements in Table 2. Description based on all adult voucher material plus SEM images of eight adult specimens. Body elongate, cylindrical, broadest in region anterior to ventral sucker, tapering slightly posteriorly. Tegument armed with alternating rows of partially overlapping comb-like scales; distal portion of scales forming up to 15 distinct tendrils. Eyespot pigment sparsely scattered in forebody. Oral sucker terminal, partially retractable, infundibuliform, broadest in anterior region with distinct reduction in diameter about mid-length continuing through to posterior margin; margin of anterior portion bearing crown of 14 bifid tentacles; outer branch of tentacles broad, conoid; inner branch of tentacles longer than outer branch, tendrillike, tapering distally. Ventral sucker in anterior third of body, round, far smaller than oral sucker. Prepharynx short, distinct, sigmoid or looped. Pharynx ellipsoidal to dolioform, in line with oral sucker or rotated up to 90 °. Oesophagus short, bifurcates just posterior to pharynx with proximal section reaching to ventral surface and opening as ‘ ventral anus’, and distal portion expanding to form caecum. Caecum single, broadest in anterior region, passes from mid-forebody to close to posterior extremity, terminates blindly; gastrodermis well developed. Testes two, ellipsoidal, tandem, contiguous, in midhindbody. Vasa deferentia narrow, passing relatively direct from testes to cirrus-sac. Cirrus-sac elongate, cylindrical, winding, reaching from just anterior to ovary to level of ventral sucker. Internal seminal vesicle tubular, loops once about mid-length, occupies about half length of cirrus-sac. Pars prostatica distinct, vesicular, about half length of internal seminal vesicle, lined with anuclear, cell-like bodies. Ejaculatory duct short, curves back dorsally from pars prostatica to open into genital atrium. Genital atrium broad, dorsal to and larger than ventral sucker. Genital pore large, round to irregular, opening dorsally at level of ventral sucker. Ovary pre-testicular, pyriform, narrowing posteriorly toward union with oötype. Mehlis’ gland indistinct. Laurer’s canal opens dorsally at level of ovary. Canalicular seminal vesicle saccular, contiguous with and dorsal to ovary. Uterus narrow, passes posteriorly from oötype to anterior testis, loops back, gently winding anteriorly, forming muscular metraterm about mid-level of pars prostatica, opening into genital atrium adjacent to ejaculatory duct. Eggs few, oval, operculate, large; length often exceeding that of ovary. Vitellarium follicular, restricted to hindbody; fields reaching from about mid-cirrus-sac to near posterior extremity; dorsal, lateral and ventral fields confluent, wrap around body from dorsal midline to ventrosinistral and ventrodextral regions anterior to testes, wrap entire body posterior to testes. Vitelline reservoir between ovary and anterior testis; collecting ducts indistinct. Excretory pore terminal; excretory vesicle Y-shaped, passes anteriorly, bifurcating in testicular region, ducts passing anteriorly sinistrally and dextrally, terminating as enlarged pyriform sacs on either side of cirrus-sac. Description of redia (Fig. 7 C): Measurements in Table 6. Description based on all voucher material. Body elongate, broadest anteriorly, tapering slightly posteriorly. Cercarial embryos numerous, poorly developed. Mouth subterminal. Pharynx cylindrical to hourglass-shaped. Intestine short, saclike, immediately posterior to pharynx. Description of cercaria (Fig 7 D): Measurements in Table 6. Description based on all voucher material. Oculate gymnocephalous cercariae. Body elongate, ellipsoidal. Eyespots two, in anterior forebody; additional pigment dispersed in forebody. Oral sucker terminal, infundibuliform. Ventral sucker post-equatorial, round. Prepharynx short, passes between eyespots. Pharynx ellipsoidal. Caecum single, terminating in region dorsal to ventral sucker. Tail longer than body, bipartite; proximal portion bearing series of lateral projections; distal portion scaled, lacking lateral projections. Excretory vesicle Y-shaped, arms extending to anterior margin of ventral sucker, stem extending posterior to ventral sucker; posterior collecting duct visible to first few scales of distal potion of tail; anterior collecting ducts not visible beyond ventral sucker. Genital primordia dorsal to ventral sucker. Remarks: Gorgocephalus kyphosi has now been demonstrated to occur in four species of Kyphosus, the broadest definitive host range of any known member of the family. This species also occurs across a broad geographic range, from eastern and southern Australia to French Polynesia. Despite the discovery of two new species of gorgocephalid, which are morphologically similar to G. kyphosi, all previous records of this species subsequent to the type description have proven accurate. The previously available 28 S rDNA sequence for G. kyphosi of Olson et al. (2003), generated from specimens from K. vaigiensis collected off Lizard Island, fell into a well-supported clade of specimens of this species from Lizard Island. Bray (2005 b) and Bray & Cribb (2005) also reported G. kyphosi from Lizard Island, but again these specimens were all from K. vaigiensis; the morphologically similar G. graboides has only been recovered from K. cinerascens. No molecular data are available to confirm the identity of specimens reported from Moorea, French Polynesia (Bray & Cribb, 2005), but that report is again based on specimens recovered from K. vaigiensis. Off Rangiroa, Tuamotu Islands, French Polynesia, we obtained only G. kyphosi and G. yaaji, despite examination of specimens comprising three species of Kyphosus. Thus, we have little doubt that the specimens from Moorea represent G. kyphosi. Both Manter (1966), in the original type description, and Yamaguti (1971), in study of the same material, reported the number of oral sucker tentacles of Gorgocephalus kyphosi at 14 – 15. We find that, because of the bifid nature of these tentacles, the fact that they are often partially retracted and that they generally overlay one-another in slide-mounted specimens, it is difficult to be confident in the accuracy of counts of these tentacles obtained during light-microscopy. This difficulty was also noted by Bray & Cribb (2005), who reported the number of oral sucker tentacles in G. yaaji as 14 – 17. We obtained SEM images of the oral sucker of eight individual adult G. kyphosi, including specimens from three Australian localities and French Polynesia. Although not all tentacles were visible in some of these specimens, in all of those in which an accurate count was possible, the number of tentacles was determined to be 14. Furthermore, the number of oral sucker tentacles was determined to be 14 for all species studied here, and Zhukov (1983) reported the number of tentacles in G. manteri at 14. It appears that all presently recognized species of Gorgocephalus possess 14 oral sucker tentacles. Manter (1966) described the anterior region of the oesophagus as a ‘ dorsal sac’ from which the duct opening as the ventral anus arises. Yamaguti (1971) referred to these structures collectively as the ‘ post-pharyngeal vesicle’. Both of these authors also described these structures as separated from the oesophagus proper by a muscular sphincter. Bray & Cribb (2005) did not observe these features in specimens of G. yaaji or in serially sectioned specimens of G. kyphosi. We did not observe these features either, although we did not study any sectioned specimens. If such features are present, they are subtle and difficult to observe in whole-mounted specimens. Thus, we agree with Bray & Cribb (2005) that these features are unlikely to be useful for the differentiation of species. We have discovered two intermediate hosts for Gorgocephalus kyphosi, Bembicium auratum and Echinolittorina vidua, both gastropods of the family Littorinidae. The distribution of these two gastropods suggests that G. kyphosi utilizes additional intermediate host species throughout its range. Extant species of the genus Bembicium occur only on the coasts of mainland Australia, Tasmania, Lord Howe Island and Norfolk Island (Reid, 1988). Bembicium auratum ranges from South Australia to Lizard Island on the GBR (Reid, 1988), covering the Australian range of G. kyphosi. Echinolittorina vidua ranges throughout the central IWP, but not to French Polynesia (Reid, 2007). Thus, Polynesian populations of G. kyphosi must utilize an intermediate host different from those used by Australian populations, although this host will undoubtedly be a species of the Littorinidae. No morphological differences were found between the intramolluscan stages of Gorgocephalus kyphosi obtained from Bembicium auratum and Echinolittorina vidua. The cercariae of G. kyphosi are similar to those of the family described previously (O’Dwyer et al., 2015; Huston et al., 2016) and those of Gorgocephalus graboides described here. Although there are some subtle differences between intramolluscan gorgocephalids (see Remarks sections for G. yaaji and G. graboides), matching of these stages to adult forms using molecular markers is likely the best approach for future work elucidating life cycles in this family.	en	Huston, Daniel C., Cutmore, Scott C., Miller, Terrence L., Sasal, Pierre, Smit, Nico J., Cribb, Thomas H. (2021): Gorgocephalidae (Digenea: Lepocreadioidea) in the Indo-West Pacific: new species, life-cycle data and perspectives on species delineation over geographic range. Zoological Journal of the Linnean Society 193 (4): 1416-1455, DOI: 10.1093/zoolinnean/zlab002, URL: https://doi.org/10.1093/zoolinnean/zlab002
03815953FFA02E09147F7ACDFEF81AF3.taxon	description	(FIGS 9 D – F, 10; TABLES 3, 6) Synonym: ‘ Gorgocephalus sp. Aus’ of O’Dwyer et al. (2015). Type host and locality: Kyphosus vaigiensis (Quoy & Gaimard, 1825) (Perciformes: Kyphosidae), brassy chub from off Lizard Island, Great Barrier Reef, Queensland, Australia (14 ° 41 ’ 10 ’’ S, 145 ° 28 ’ 15 ’’ E). Records: 1, Bray & Cribb (2005); 2, O’Dwyer et al. (2015); 3, Huston et al. (2016); 4, present study. Definitive hosts: Perciformes, Kyphosidae. Kyphosus cinerascens (Forsskål, 1775), highfin chub (3, 4); Kyphosus elegans (W. K. H. Peters, 1869), Cortez sea chub (4); Kyphosus vaigiensis (Quoy & Gaimard, 1825) (1, 4). Intermediate hosts: Gastropoda, Littorinimorpha, Littorinidae. Austrolittorina unifasciata (Gray) (2, 3); Echinolittorina austrotrochoides Reid, 2007 (3); Echinolittorina cinerea (Pease, 1869) (4). Other localities: Gerringong, New South Wales, Australia (34 ° 44 ’ 18 ’’ S, 150 ° 49 ’ 29 ’’ E) (2); Kioloa, New South Wales, Australia (35 ° 33 ’ 38 ’’ S, 150 ° 22 ’ 27 ’’ E) (KI) (3); Shellharbour, New South Wales, Australia (34 ° 34 ’ 59 ’’ S, 150 ° 52 ’ E) (2); Sydney, New South Wales, Australia (33 ° 52 ’ 42 ’’ S, 151 ° 12 ’ 34 ’’ E) (2); Ulladulla, New South Wales, Australia (35 ° 21 ’ 17 ’’ S, 150 ° 27 ’ 43 ’’ E) (2); off Rangiroa, Tuamotu Islands, French Polynesia (15 ° 10 ’ 40 ’’ S, 147 ° 39 ’ 04 ’’ W) (4); Sodwana Bay, KwaZulu-Natal, South Africa (27 ° 32 ’ 24 ’’ S, 32 ° 40 ’ 41 ’’ E) (SB) (4). Voucher material (adult): Ten whole-mount and three hologenophore specimens, ex K. vaigiensis from LI (QM G 238592 – G 238604); six whole-mount and three hologenophore specimens ex K. cinerascens from RA (MNHN HEL 1447 – 1455); one whole-mount specimen ex K. elegans from RA (MNHN HEL 1456); three whole-mount and one hologenophore specimen ex K. cinerascens from SB (NMB 730); six whole-mount specimens ex K. vaigiensis from SB (NMB 731). Voucher material (intramolluscan): Eight slides of rediae and cercariae ex E. cinerea from RA (MNHN HEL 1457 – 1464). Site in host: Upper intestine (definitive); gonad / digestive gland (intermediate). Representative DNA sequences: Nineteen sequences (MW 353650 – MW 353668), using primers of Wee et al. (2017), and three sequences (MW 350141 – MW 350143), following O’Dwyer et al. (2016) (see methods) deposited for COI mtDNA; 17 sequences deposited for 5.8 S-ITS 2 - partial 28 S rDNA (MW 353931 – MW 353947); nine sequences deposited for partial 28 S rDNA (MW 353889 – MW 353897); see Supporting Information, Table S 2. Description of adult (Figs 9 D – F, 10 A – C, F: Measurements in Table 3). Description based upon all adult voucher material and SEM images of three adults. Body elongate-oval, somewhat dorsoventrally flattened, broadest in region of ventral sucker, tapering slightly posteriorly. Tegument armed with alternating rows of partially overlapping comb-like scales; distal portion of scales forming up to 18 distinct tendrils. Eyespot pigment sparsely scattered in forebody. Oral sucker terminal, partially retractable, infundibuliform, broadest in anterior region with distinct reduction in diameter about mid-length continuing through to posterior margin; margin of anterior portion bearing crown of 14 bifid tentacles; outer branch of tentacles broad, conoid; inner branch of tentacles approximately equal in length to outer, tendril-like, tapering distally. Ventral sucker in anterior third of body, round, smaller than oral sucker. Prepharynx short, distinct, sigmoid or looped. Pharynx ellipsoidal to dolioform, in line with oral sucker or rotated up to 45 °. Oesophagus short, bifurcates just posterior to pharynx with proximal section reaching to ventral surface and opening as ‘ ventral anus’, and distal portion expanding to form caecum. Caecum single, broadest in anterior region, passes from mid-forebody to close to posterior extremity, terminates blindly; gastrodermis well developed. Testes two, ellipsoidal, tandem, contiguous, in midhindbody. Vasa deferentia narrow, passing relatively direct from testes to cirrus-sac. Cirrus-sac elongate, cylindrical, winding, reaching from anterior testis to level of ventral sucker; anterior portion curves back posteriorly from ventral sucker to genital atrium. Internal seminal vesicle tubular, bends slightly about mid-length, occupies about half length of cirrus-sac. Pars prostatica distinct, vesicular, approximately equal in length to internal seminal vesicle, lined with anuclear cell-like bodies. Ejaculatory duct long, occupies recurved portion of cirrus-sac. Genital atrium broad, dorsal and approximately equal in size to ventral sucker. Genital pore large, round to irregular, opening dorsodextrally at level of ventral sucker. Ovary pre-testicular, ellipsoidal to subglobular. Mehlis’ gland between ovary and anterior testis. Laurer’s canal opens dorsally posterior to ovary. Canalicular seminal vesicle saccular, contiguous with and dorsal to ovary. Uterus narrow, passes posteriorly from oötype to anterior testis, loops back, gently winding anteriorly, forming muscular metraterm about mid-level of pars prostatica, opening into genital atrium adjacent to ejaculatory duct. Eggs few, oval, operculate, large; length of eggs often exceeding that of ovary. Vitellarium follicular, in fore- and hindbody, fields reaching from pharyngoesophageal region to near posterior extremity; dorsal, lateral and ventral fields confluent, wrap around body from dorsal midline to ventrosinistral and ventrodextral regions anterior to testes, wrap entire body posterior to testes. Vitelline reservoir between ovary and anterior testis; collecting ducts indistinct. Excretory pore terminal; excretory vesicle Y-shaped, passes anteriorly, bifurcating in testicular region, ducts passing anteriorly sinistrally and dextrally, terminating as enlarged pyriform sacs on either side of cirrus-sac. Description of redia (Fig. 10 D): Measurements in Table 6. Description based on voucher material. Body ellipsoidal, broadest posteriorly; distinctive protuberance arising from posterior extremity in most specimens. Cercarial embryos numerous, poorly developed. Mouth subterminal. Pharynx ellipsoidal. Intestine short, globular, immediately posterior and subequal in size to pharynx. Description of cercaria (Fig. 10 E): Measurements in Table 6. Description based on voucher material. Oculate gymnocephalous cercariae. Body elongate, ellipsoidal. Eyespots two, in anterior forebody; eyespot lenses present in live naturally emerged specimens, not present in immature specimens. Oral sucker subterminal, infundibuliform. Ventral sucker post-equatorial, round. Prepharynx short, passes between eyespots. Pharynx ellipsoidal. Caecum single, terminating near anterior margin of ventral sucker. Tail bipartite; proximal portion bearing series of lateral projections; distal portion scaled, lacking lateral projections. Excretory vesicle Y-shaped; arms extending to ventral sucker, stem extending to near posterior extremity; posterior collecting duct visible to first few scales of distal portion of tail; anterior collecting ducts not visible beyond ventral sucker. Genital primordia darkly stained, dorsal to ventral sucker. Remarks: Gorgocephalus yaaji occurs across a wider geographic range than any other species of the family. Indeed, to our knowledge the finding of G. yaaji in French Polynesia, South Africa, and in between, is the first report, supported by molecular data, of naturally occurring populations of a single marine digenean species occurring across the whole breadth of the IWP. Although it has fewer definitive host records than G. kyphosi, three gastropod intermediate hosts are known for G. yaaji, the most for any species of the family. O’Dwyer et al. (2015) described the first gorgocephalid cercariae from the littorinid A. unifasciata, but did not connect these infections to an adult gorgocephalid, because their sequences did not match those of G. kyphosi from the study of Olson et al. (2003), the only sequences available for the family at that time. Huston et al. (2016) described the cercariae of G. yaaji from Echinolittorina austrotrochoides from Lizard Island, GBR, and determined that, based on the difference in host, molecular differences in the ITS 2 and 28 S rDNA gene-regions, and morphological differences, the infections characterized by O’Dwyer et al. (2015) were likely those of an undescribed species. However, by adding an additional molecular marker (COI) and performing expanded phylogenetic study of the family, we have demonstrated that the intramolluscan infections described by O’Dwyer et al. (2015) are best interpreted as representative of G. yaaji. The host, molecular and morphological differences reported by Huston et al. (2016) between their material and that of O’Dwyer et al. (2015) are clearly within the bounds of intraspecific variation for G. yaaji. Huston et al. (2016) noted that the morphological differences between their cercarial specimens of Gorgocephalus yaaji and those of O’Dwyer et al. (2015) may have been a result of differences between ‘ naturally emerged’ cercariae and cercariae excised from gastropods. O’Dwyer et al. (2015) studied live and fixed cercariae dissected from gastropods, whereas Huston et al. (2016) studied live and fixed naturally emerged cercariae. Naturally emerged cercariae are generally considered as ‘ mature’, whereas cercariae obtained from dissection of a gastropod may include mature and immature individuals. As stated above, the morphometric differences observed between G. yaaji cercariae appear due to normal intraspecific variation. However, one of the key morphological differences between the material of O’Dwyer et al. (2015) and Huston et al. (2016) was the observation of distinct ‘ lenses’ in the eyespots of the live cercariae from the latter study. O’Dwyer et al. (2015) studied live material from dissected gastropods and is unlikely to have missed such a distinctive feature if it was present. Huston et al. (2016) interpreted this lack of eyespot lenses as indicative of a species-level difference. However, we did not obtain naturally emerged cercariae of G. yaaji from Echinolittorina cinerea in French Polynesia, although we did study live material from dissected gastropods. We did not observe eyespot lenses in the French Polynesian cercariae. Thus, as all of these cercariae are conspecific, we interpret the presence of eyespot lenses in the cercariae from the study of Huston et al. (2016) as a feature that is likely present only in mature, naturally emerged cercariae. Five of the six known intermediate host records for gorgocephalids are attributable to Gorgocephalus kyphosi and G. yaaji. These two species have yet to be confirmed as having overlapping intermediate host ranges, but this remains possible. We obtained naturally emerged cercariae of G. kyphosi from an infected Echinolittorina vidua from Lizard Island, GBR, the same locality from which Huston et al. (2016) obtained naturally emerged cercariae of G. yaaji from E. austrotrochoides. Although there are no clear morphometric differences between the cercariae of G. kyphosi and G. yaaji, we did not observe eyespot lenses in the cercariae of G. kyphosi. However, as naturally emerged cercariae were studied from only a few infected gastropods, at present it is difficult to have confidence in the validity of this character for species differentiation. Additionally, Huston et al. (2016) described the rediae of G. yaaji from infected E. austrochoides from Lizard Island, GBR, with a strange posterior ‘ protuberance’. We observed the same feature in the rediae of G. yaaji from infected E. cinerea from Rangiroa, French Polynesia. This feature was not present in any of the rediae of G. kyphosi that we observed. We do note that this ‘ protuberance’ was not reported by O’Dwyer et al. (2015), so this would seem a somewhat tenuous feature for the differentiation of species. Despite repeated attempts, we were never able to obtain naturally emerged cercariae of G. kyphosi from Bembicium auratum. Considering the cryptic morphology of gorgocephalid cercariae, and the difficulty of obtaining naturally emerged specimens, use of molecular data for the identification of intramolluscan gorgocephalid infections will be required in most cases. As noted above, Bray & Cribb (2005) reported the number of oral sucker tentacles in G. yaaji as 14 – 17; based on our SEM images we believe that this species, and all known gorgocephalids, have only 14 bifid tentacles. Although Manter (1966) reported G. kyphosi from both the pyloric caeca and intestine of K. sydneyanus, Bray & Cribb (2005) found that in K. vaigiensis from Lizard Island, G. kyphosi was restricted to the pyloric caeca whereas G. yaaji was found in the intestine. Our observations agree. With the exception of G. yaaji, all species of Gorgocephalus we collected were found only in the pyloric caeca. We found G. yaaji in the upper intestine, just posterior to the pyloric caeca.	en	Huston, Daniel C., Cutmore, Scott C., Miller, Terrence L., Sasal, Pierre, Smit, Nico J., Cribb, Thomas H. (2021): Gorgocephalidae (Digenea: Lepocreadioidea) in the Indo-West Pacific: new species, life-cycle data and perspectives on species delineation over geographic range. Zoological Journal of the Linnean Society 193 (4): 1416-1455, DOI: 10.1093/zoolinnean/zlab002, URL: https://doi.org/10.1093/zoolinnean/zlab002
03815953FFAC2E0917E27A36FD841ECF.taxon	description	(FIGS 11, 12 A – C; TABLES 4, 6) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org: act: 7 C 5053 D 1 - DE 14 - 400 E-A 8 FC- 36 F 6 E 1 A 305 B 6. Type host and locality: Kyphosus gladius Knudsen & Clements (Perciformes: Kyphosidae), gladius sea chub, from off Point Peron, Rockingham, Western Australia (32 ° 15 ’ 59 ’’ S, 115 ° 41 ’ 03 ’’ E) (PP). Other hosts (definitive): Kyphosus sydneyanus (Günther, 1886) (Perciformes: Kyphosidae), silver drummer; Kyphosus cinerascens (Forsskål, 1775), highfin chub (Perciformes: Kyphosidae). Other localities: Off Rottnest Island, Western Australia (32 ° 59 ’ 04 ’’ S, 115 ° 31 ’ 06 ’’ E) (RI); Sodwana Bay, KwaZulu-Natal, South Africa (27 ° 32 ’ 24 ’’ S, 32 ° 40 ’ 41 ’’ E). Type material: Holotype (WAM V 9670) ex K. gladius from off PP. Paratypes: eight whole-mount specimens and two hologenophores ex K. gladius from PP (WAM V 9671 – 9680); one whole-mount and three hologenophores ex K. sydneyanus from RI (WAM V 9681 – 9684). Additional voucher material (adult): Eight wholemount and two hologenophore specimens, ex K. cinerascens from SB (NMB 732).	en	Huston, Daniel C., Cutmore, Scott C., Miller, Terrence L., Sasal, Pierre, Smit, Nico J., Cribb, Thomas H. (2021): Gorgocephalidae (Digenea: Lepocreadioidea) in the Indo-West Pacific: new species, life-cycle data and perspectives on species delineation over geographic range. Zoological Journal of the Linnean Society 193 (4): 1416-1455, DOI: 10.1093/zoolinnean/zlab002, URL: https://doi.org/10.1093/zoolinnean/zlab002
03815953FFAB2E33146879B1FD3A1D87.taxon	description	(FIGS 12 D – F, 13; TABLES 4, 6) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org: act: D 684 AF 8 B- 5 CF 6 - 40 A 0 - 91 AD- 7 B 26 A 304 D 47 B. Type host and locality: Kyphosus cinerascens (Forsskål, 1775), highfin chub (Perciformes: Kyphosidae) from off Lizard Island, Great Barrier Reef, Queensland, Australia (14 ° 41 ’ 10 ’’ S, 145 ° 28 ’ 15 ’’ E). Other hosts (intermediate): Echinolittorina vidua (G o u l d, 1 8 5 9) (G a s t r o p o d a: L i t t o r i n i m o r p h a: Littorinidae). Type material: Holotype (QM G 238605) ex K. cinerascens from off LI. Paratypes: 14 whole mount and three hologenophore specimens ex K. cinerascens from LI (QM G 238606 – G 238622). Additional voucher material (intramolluscan): Five slides of cercariae and rediae ex E. vidua from LI (QM G 238623 – G 238627). Site in host: Pyloric caeca (definitive); gonad / digestive gland (intermediate). Representative DNA sequences: Six sequences deposited for COI mtDNA (MW 353677 – MW 353682); six sequences deposited for 5.8 S-ITS 2 - partial 28 S rDNA (MW 353959 – MW 353964); four sequences deposited for partial 28 S rDNA (MW 353905 – MW 353908); see Supporting Information, Table S 2. Etymology: This species is named for its resemblance to the monsters from the Tremors films, ‘ graboids’. Graboids are blind, subterranean, worm-like predators with grasping tentacles that emerge from their beaklike maws. Graboids even have complex life-cycles, transitioning through several radically different phenotypes. The name is formed by combination of ‘ graboid’ and a Latinized Greek suffix indicating a resemblance or likeness, ‘ oides’. Description of adult (Figs 12 D – F, 13 A, B, E): Measurements in Table 4. Description based on type material and SEM images of three adult specimens. Body elongate, cylindrical, broadest in region of ventral sucker, tapering slightly posteriorly. Tegument armed with alternating rows of partially overlapping comblike scales; distal portion of scales forming up to 15 distinct tendrils. Eyespot pigment sparsely scattered in forebody and anterior third of hindbody. Oral sucker terminal, partially retractable, infundibuliform, broadest in anterior region with distinct reduction in diameter about mid-length continuing through to posterior margin; margin of anterior portion bearing crown of 14 bifid tentacles; outer branch of tentacles broad, conoid; inner branch of tentacles longer than outer, tendril-like, tapering distally. Ventral sucker in anterior third of body, round, smaller than oral sucker. Prepharynx short, distinct, sigmoid or looped. Pharynx ellipsoidal to dolioform, in line with oral sucker or rotated up to 90 °. Oesophagus short, bifurcates just posterior to pharynx with proximal section reaching to ventral surface and opening as ‘ ventral anus’, and distal portion expanding to form caecum. Caecum single, broadest in anterior region, passes from midforebody to close to posterior extremity, terminates blindly; gastrodermis well developed. Testes two, ellipsoidal, tandem, contiguous or separated, in mid hindbody. Vasa deferentia narrow, passing relatively direct from testes to cirrus-sac. Cirrus-sac elongate, cylindrical, gently winding, reaching from just anterior to ovary to posterior margin of ventral sucker. Internal seminal vesicle tubular, loops once about mid-length, occupies less than half length of cirrus-sac. Pars prostatica distinct, vesicular, less than half length of internal seminal vesicle, lined with anuclear cell-like bodies. Ejaculatory duct distinct, approximately equal in length to, or longer than, pars prostatica; opens into genital atrium. Genital atrium narrow, posterior-dorsal and subequal to ventral sucker. Genital pore small, round to irregular, opening dorsally at level of ventral sucker. Ovary pre-testicular, pyriform, narrowing posteriorly toward union with oötype. Mehlis’ gland indistinct. Laurer’s canal opens dorsally at level of ovary. Canalicular seminal vesicle saccular, contiguous with and dorsal to ovary. Uterus narrow, passes posteriorly from oötype to anterior testis, loops back, gently winding anteriorly, forming muscular metraterm about mid-level of pars prostatica, opening into genital atrium adjacent to ejaculatory duct. Eggs few, oval, operculate, large; length often exceeding that of ovary. Vitellarium follicular, restricted to hindbody; fields reaching from about mid-cirrus-sac to near posterior extremity; dorsal, lateral and ventral fields confluent, wrap around body from dorsal midline to ventrosinistral and ventrodextral regions anterior to testes, wrap entire body posterior to testes. Vitelline reservoir between ovary and anterior testis; collecting ducts indistinct. Excretory pore terminal; excretory vesicle Y-shaped, passes anteriorly, bifurcating in testicular region, ducts passing anteriorly sinistrally and dextrally, terminating as enlarged pyriform sacs on either side of cirrus-sac. Description of redia (Fig 13 C): Measurements in Table 6. Description based on voucher material. Body elongate, broadest anteriorly, tapering posteriorly. Cercarial embryos numerous, poorly developed. Mouth terminal. Pharynx dolioform. Intestine short, globular, immediately posterior and subequal in size to pharynx. Description of cercaria (Fig 13 E): Measurements in Table 6. Description based on voucher material. Oculate gymnocephalous cercariae. Body elongate, fusiform. Eyespots two, in anterior forebody; additional pigment conspicuous, dispersed in forebody. Oral sucker terminal, infundibuliform. Ventral sucker post-equatorial, round. Prepharynx short, passes between eyespots. Pharynx ellipsoidal. Caecum single, terminating in region dorsal to ventral sucker. Tail longer than body, bipartite; proximal portion bearing series of lateral projections; distal portion scaled, lacking lateral projections. Excretory vesicle Y-shaped, arms extending to ventral sucker, stem extending to near posterior extremity; posterior collecting duct visible to first few scales of distal potion of tail; anterior collecting ducts not visible beyond ventral sucker. Genital primordia darkly stained, dorsal to ventral sucker. Remarks: There are no clear morphometric features that differentiate this species from Gorgocephalus kyphosi, and these two species have overlapping host ranges at both the definitive and intermediate host level. However, the cirrus-sac can again be used for differentiation. In G. kyphosi, the ejaculatory duct is short and the internal seminal vesicle and pars prostatica each occupy about half of the cirrus-sac, whereas in G. graboides the internal seminal vesicle occupies less than half of the cirrus-sac and the pars prostatica is less than half the length of the internal seminal vesicle; the remaining space is occupied by a long, distinct ejaculatory duct, which is about as long as, or longer than, the pars prostatica. Furthermore, the genital atrium is larger than the ventral sucker in specimens of G. kyphosi, whereas in G. graboides the two features are similar in size. From Gorgocephalus euryaleae, G. graboides differs in having a shorter pars prostatica (occupying less than half, rather than more than half, of the cirrus-sac) and in having a longer ejaculatory duct (equal or greater in length than the pars prostatica vs. shorter than the pars prostatica). Although both species share K. cinerascens as a host, they appear to be geographically isolated from one another. From Gorgocephalus manteri, G. graboides differs primarily in having a larger body and in having vitelline follicles restricted to the hindbody, rather than having them extend into the forebody. The cirrus-sac of G. graboides also lacks the strong sigmoidal shape of that of G. manteri and based on the calculations of Bray & Cribb (2005), G. manteri has, as a percentage of body length, a much greater body width (28 – 34 % vs. 8 – 11 %), lesser ovary to ventral sucker distance (~ 5 % vs. 27 – 33 %) and greater ovary to testis distance (~ 17 % vs. 4 – 9 %) than G. graboides. Gorgocephalus graboides is easily distinguished from G. yaaji in having a far less dorsoventrally flattened body, and in having vitelline follicles restricted to the hindbody, rather than having them extend into the forebody. Gorgocephalus graboides also differs from G. yaaji morphometrically, namely in having, as a percentage of body length, a shorter forebody (21 – 26 % vs. 31 – 42 %), a shorter pharynx (3.0 – 4.3 % vs. 6.0 – 10.2 %) and a longer testis to ventral sucker distance (36 – 44 % vs. 22 – 32 %). Gorgocephalus graboides also has a lesser pharynx length to oral sucker length ratio than G. yaaji (0.27 – 0.35 vs. 0.37 – 0.55). The inner and outer portions of the oral sucker tentacles of G. yaaji are approximately equal in length, rather than having the inner portion longer like in G. graboides and the tegument scales of G. yaaji have more posterior tendrils than those of G. graboides (up to 18 vs. up to 15). Lastly, the cirrus-sac of G. graboides is less robust than that of G. yaaji and does not have the anterior portion recurved.	en	Huston, Daniel C., Cutmore, Scott C., Miller, Terrence L., Sasal, Pierre, Smit, Nico J., Cribb, Thomas H. (2021): Gorgocephalidae (Digenea: Lepocreadioidea) in the Indo-West Pacific: new species, life-cycle data and perspectives on species delineation over geographic range. Zoological Journal of the Linnean Society 193 (4): 1416-1455, DOI: 10.1093/zoolinnean/zlab002, URL: https://doi.org/10.1093/zoolinnean/zlab002
