Two new species of Pseudorhabdosynochus Yamaguti, 1958 (Monogenea: Diplectanidae) from the deep-sea grouper Epinephelus morrhua (Val.) (Perciformes: Serranidae) off New Caledonia
Abstract:Three species of monogeneans were collected from Epinephelus morrhua, a deep-sea grouper from the external slope of the coral reef, off New Caledonia, South Pacific, and are the first parasites recorded from this fish species. Pseudorhabdosynochus morrhua n. sp. is characterised by: a sclerotised vagina with small sclerotised chambers and a short secondary canal; squamodiscs with central rows of rodlets which form closed ovals; and a scaly tegument. P. variabilis n. sp. has: a male quadriloculate organ with a … Show more
“…Most authors have emphasized the importance of the morphological structure of the sclerotised vagina for Pseudorhabdosynochus species identification (Chaabane, Neifar & Justine, 2015; Justine, 2005a; Justine, 2005b; Justine, 2007a; Justine, 2007b; Justine, 2008c; Justine, 2010; Justine, Dupoux & Cribb, 2009; Justine et al, 2010; Justine & Sigura, 2007; Knoff et al, 2015; Mendoza-Franco, Violante-González & Herrera, 2011; Neifar & Euzet, 2007), although the quadriloculate organ and the hard parts of the host attachment apparatus (haptor) including the squamodisc are additional characters for species diagnosis. 10.7717/peerj.2233/fig-4Figure 4Homologies of various parts of the sclerotised vagina of Pseudorhabdosynochus sulamericanus compared to a general diagram.Colours are similar in homologous parts.…”
Section: Resultsmentioning
confidence: 99%
“…In addition, the anterior chamber of its male copulatory organ has a very thin wall (vs as sclerotised as other chambers in P. sulamericanus ) (Justine, 2008c). …”
Section: Resultsmentioning
confidence: 99%
“…More than 80 species of Pseudorhabdosynochus are known; they are generally extremely species-specific, i.e., a species is found only on one species of host (Justine, 2005a; Justine, 2005b; Justine, 2007a; Justine, 2007b; Justine, 2008b; Justine, 2008c; Justine et al, 2010; Justine & Sigura, 2007; Sigura & Justine, 2008); however, Schoelinck, Cruaud & Justine (2012) recently demonstrated, on morphological and molecular bases, that P. cyanopodus occurs on two sympatric species of deep-sea groupers that inhabit the outer slope off the barrier reef of New Caledonia, South Pacific. These are Epinephelus cyanopodus and E. chlorostigma (Schoelinck, Cruaud & Justine, 2012).…”
Section: Discussionmentioning
confidence: 99%
“…Groupers (Serranidae, Epinephelinae) are known to harbour rich parasitic fauna (Cribb et al, 2002; Justine et al, 2010), including an exceptionally high number of diplectanid monogenean species belonging to the genus Pseudorhabdosynochus Yamaguti, 1958 (Hinsinger & Justine, 2006; Justine, 2005a; Justine, 2005b; Justine, 2007a; Justine, 2007b; Justine, 2008c; Justine, 2010; Justine, Dupoux & Cribb, 2009; Justine et al, 2010; Justine & Sigura, 2007; Kritsky, Bakenhaster & Adams, 2015; Neifar & Euzet, 2007; Schoelinck & Justine, 2011; Zeng & Yang, 2007) and some species from other genera (Journo & Justine, 2006; Justine, 2007a; Justine, 2008a; Justine & Euzet, 2006; Justine & Henry, 2010; Sigura & Justine, 2008). Most grouper species live in tropical seas, particularly in coral reefs, and are thus shallow-water species.…”
Little is known of the diversity of the monogenean parasites infesting deep-sea groupers, and there is even less information available about their geographic distributions within the ranges of their hosts. To improve our understanding of these host-parasite relationships we conducted parasitological evaluations of the deep-water Haifa grouper Hyporthodus haifensis from the southern Mediterranean off Tunisia and Libya. We collected more than one species of diplectanid monogeneans from this host, but among these only one dominant species was abundant. This proved to be morphologically very similar to Pseudorhabdosynochus sulamericanus Santos, Buchmann & Gibson, 2000, a species originally described from the congeneric host H. niveatus off Brazil and also recorded from H. niveatus and H. nigritus off Florida. Here, we conducted a morphological comparison between newly collected specimens and those previously deposited in museum collections by other authors. Further, we used COI barcoding to ascertain the specific identity of the three host species to better elucidate the circumstances that might explain the unexpectedly broad distribution of P. sulamericanus. We assigned our specimens from H. haifensis to P. sulamericanus primarily on the basis of morphological characteristics of the sclerotized vagina. We also noted morphological characteristics of eastern and western Atlantic specimens that are not clearly described or not given in previous descriptions and so prepared a redescription of the species. We confirmed, by COI barcoding, that no sister-species relationships were evident among the three hosts of P. sulamericanus. Our observation that P. sulamericanus infects unrelated host species with putatively allopatric distributions was unexpected given the very limited dispersive capabilities and the high degree of host specificity common to members of Pseudorhabdosynochus. This transatlantic distribution raises questions with regard to phylogeography and assumptions about the allopatry of Atlantic grouper species from the Americas and Afro-Eurasia. Here, we propose some hypothetical explanations for our findings.
“…Most authors have emphasized the importance of the morphological structure of the sclerotised vagina for Pseudorhabdosynochus species identification (Chaabane, Neifar & Justine, 2015; Justine, 2005a; Justine, 2005b; Justine, 2007a; Justine, 2007b; Justine, 2008c; Justine, 2010; Justine, Dupoux & Cribb, 2009; Justine et al, 2010; Justine & Sigura, 2007; Knoff et al, 2015; Mendoza-Franco, Violante-González & Herrera, 2011; Neifar & Euzet, 2007), although the quadriloculate organ and the hard parts of the host attachment apparatus (haptor) including the squamodisc are additional characters for species diagnosis. 10.7717/peerj.2233/fig-4Figure 4Homologies of various parts of the sclerotised vagina of Pseudorhabdosynochus sulamericanus compared to a general diagram.Colours are similar in homologous parts.…”
Section: Resultsmentioning
confidence: 99%
“…In addition, the anterior chamber of its male copulatory organ has a very thin wall (vs as sclerotised as other chambers in P. sulamericanus ) (Justine, 2008c). …”
Section: Resultsmentioning
confidence: 99%
“…More than 80 species of Pseudorhabdosynochus are known; they are generally extremely species-specific, i.e., a species is found only on one species of host (Justine, 2005a; Justine, 2005b; Justine, 2007a; Justine, 2007b; Justine, 2008b; Justine, 2008c; Justine et al, 2010; Justine & Sigura, 2007; Sigura & Justine, 2008); however, Schoelinck, Cruaud & Justine (2012) recently demonstrated, on morphological and molecular bases, that P. cyanopodus occurs on two sympatric species of deep-sea groupers that inhabit the outer slope off the barrier reef of New Caledonia, South Pacific. These are Epinephelus cyanopodus and E. chlorostigma (Schoelinck, Cruaud & Justine, 2012).…”
Section: Discussionmentioning
confidence: 99%
“…Groupers (Serranidae, Epinephelinae) are known to harbour rich parasitic fauna (Cribb et al, 2002; Justine et al, 2010), including an exceptionally high number of diplectanid monogenean species belonging to the genus Pseudorhabdosynochus Yamaguti, 1958 (Hinsinger & Justine, 2006; Justine, 2005a; Justine, 2005b; Justine, 2007a; Justine, 2007b; Justine, 2008c; Justine, 2010; Justine, Dupoux & Cribb, 2009; Justine et al, 2010; Justine & Sigura, 2007; Kritsky, Bakenhaster & Adams, 2015; Neifar & Euzet, 2007; Schoelinck & Justine, 2011; Zeng & Yang, 2007) and some species from other genera (Journo & Justine, 2006; Justine, 2007a; Justine, 2008a; Justine & Euzet, 2006; Justine & Henry, 2010; Sigura & Justine, 2008). Most grouper species live in tropical seas, particularly in coral reefs, and are thus shallow-water species.…”
Little is known of the diversity of the monogenean parasites infesting deep-sea groupers, and there is even less information available about their geographic distributions within the ranges of their hosts. To improve our understanding of these host-parasite relationships we conducted parasitological evaluations of the deep-water Haifa grouper Hyporthodus haifensis from the southern Mediterranean off Tunisia and Libya. We collected more than one species of diplectanid monogeneans from this host, but among these only one dominant species was abundant. This proved to be morphologically very similar to Pseudorhabdosynochus sulamericanus Santos, Buchmann & Gibson, 2000, a species originally described from the congeneric host H. niveatus off Brazil and also recorded from H. niveatus and H. nigritus off Florida. Here, we conducted a morphological comparison between newly collected specimens and those previously deposited in museum collections by other authors. Further, we used COI barcoding to ascertain the specific identity of the three host species to better elucidate the circumstances that might explain the unexpectedly broad distribution of P. sulamericanus. We assigned our specimens from H. haifensis to P. sulamericanus primarily on the basis of morphological characteristics of the sclerotized vagina. We also noted morphological characteristics of eastern and western Atlantic specimens that are not clearly described or not given in previous descriptions and so prepared a redescription of the species. We confirmed, by COI barcoding, that no sister-species relationships were evident among the three hosts of P. sulamericanus. Our observation that P. sulamericanus infects unrelated host species with putatively allopatric distributions was unexpected given the very limited dispersive capabilities and the high degree of host specificity common to members of Pseudorhabdosynochus. This transatlantic distribution raises questions with regard to phylogeography and assumptions about the allopatry of Atlantic grouper species from the Americas and Afro-Eurasia. Here, we propose some hypothetical explanations for our findings.
Gill diplectanid monogeneans from the camouflage grouper Epinephelus polyphekadion (Bleeker) collected in the coral reef lagoon of New Caledonia, South Pacific, comprise four species. Very few monogeneans were found in most fish examined. Pseudorhabdosynochus dionysos n. sp. has a sclerotised vagina with a robust trumpet, a robust primary canal and two chambers of similar size; it is close to P. bacchus Sigura, Chauvet & Justine, 2007. P. viscosus n. sp. has a sclerotised vagina with a robust trumpet, long primary canal with an extremely thin wall and two small chambers, and a male quadriloculate organ with a characteristic thickening at the extremity of its cone. P. crassus n. sp., the most abundant species, has a sclerotised vagina with a thin-walled trumpet, thin-walled primary canal which is always coiled anteriorly and two small chambers. P. huitoe Justine, 2007, P. manifestus Justine & Sigura, 2007 and P. crassus have very similar sclerotised vaginae; however, species of this 'huitoe complex' can be distinguished by measurements of the haptoral hard parts. A few diplectanid specimens found in a single specimen of E. polyphekadion were attributed to P. huitoe, a species originally described from E. maculatus (Bloch) and also rarely found in E. cyanopodus Richardson in New Caledonia; specimens from these three fish species are morphologically indistinguishable.
Specimens of the greasy grouper Epinephelus tauvina (Forsskål), caught off Moorea, French Polynesia, harboured four species of gill monogeneans. The diplectanid Pseudorhabdosynochus pai n. sp. is characterised by an extremely big male quadriloculate organ (inner length 77 mum, cone length 15, tube length 47), the largest of all members of the genus, and a sclerotised vagina with a very complex structure, including three secondary chambers instead of one as in most species. Pseudorhabdosynochus sp. is a species of the 'cupatus group'; this species is not formally described but various measurements are provided. The ancyrocephalid Haliotrema sp. and the capsalid Benedenia sp. were rare; they are both mentioned but not described. The diplectanid fauna of E. tauvina corresponds to the pattern already found in a clade of grouper species, the members of which often harbour both a species of the 'cupatus group' and another species of Pseudorhabdosynochus Yamaguti, 1958.
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