Terrence L. Miller

Two new cryptogonimid genera (Digenea, Cryptogonimidae) from Lutjanus bohar (Perciformes, Lutjanidae): analyses of ribosomal DNA reveals wide geographic distribution and presence of cryptic species

We describe three new species of Cryptogonimidae belonging to two new genera, Caulanus gen. nov. and Latuterus gen. nov., from the large piscivorous reef fish Lutjanus bohar Forsskål, 1775, recovered from Heron and Lizard Islands off the Great Barrier Reef and Rasdhoo Atoll, Maldives. To support our morphologically based taxonomic approach, three nuclear ribosomal DNA regions (28S, ITS1 and ITS2) were sequenced and analysed to explore the geographic distribution and integrity of the putative species recovered from these widespread localities. Sequencing of the rDNA regions included multiple replicates and revealed three distinct genotypes. Two of the observed genotypes were associated with phenotypically similar specimens of Latuterus, but were each restricted to a single locality, Lizard Island, GBR or Rasdhoo Atoll, Maldives. A posteriori analysis of the associated morphotypes revealed distinct morphological differences and these consistent differences, in combination with the consistent genetic differences led to the recognition of two distinct species in the system. Caulanus is distinguished by having oral spines, caeca which open via ani at the posterior end of the body, tandem testes and uterus that extends from the posterior end of the body to the pharynx. Latuterus is distinguished by lacking oral spines, having multiple/follicular testes, a uterus that is extensive in both fore-and hindbody and vitelline follicles which are confined to the region from the pharynx to oral sucker. Caulanus thomasi sp. nov. had identical sequences for all of the rDNA regions examined from specimens recovered from all three localities, indicating that this species has a wide Indo-Pacific distribution. The species reported here are evidently restricted to Lutjanus bohar because they were never found in large numbers of other lutjanid species sampled at the same localities.

An annotated list of fish parasites (Isopoda, Copepoda, Monogenea, Digenea, Cestoda, Nematoda) collected from Snappers and Bream (Lutjanidae, Nemipteridae, Caesionidae) in New Caledonia confirms high parasite biodiversity on coral reef fish

BackgroundCoral reefs are areas of maximum biodiversity, but the parasites of coral reef fishes, and especially their species richness, are not well known. Over an 8-year period, parasites were collected from 24 species of Lutjanidae, Nemipteridae and Caesionidae off New Caledonia, South Pacific.ResultsHost-parasite and parasite-host lists are provided, with a total of 207 host-parasite combinations and 58 parasite species identified at the species level, with 27 new host records. Results are presented for isopods, copepods, monogeneans, digeneans, cestodes and nematodes. When results are restricted to well-sampled reef fish species (sample sizeu2009>u200930), the number of host-parasite combinations is 20–25 per fish species, and the number of parasites identified at the species level is 9–13 per fish species. Lutjanids include reef-associated fish and deeper sea fish from the outer slopes of the coral reef: fish from both milieus were compared. Surprisingly, parasite biodiversity was higher in deeper sea fish than in reef fish (host-parasite combinations: 12.50 vs 10.13, number of species per fish 3.75 vs 3.00); however, we identified four biases which diminish the validity of this comparison. Finally, these results and previously published results allow us to propose a generalization of parasite biodiversity for four major families of reef-associated fishes (Lutjanidae, Nemipteridae, Serranidae and Lethrinidae): well-sampled fish have a mean of 20 host-parasite combinations per fish species, and the number of parasites identified at the species level is 10 per fish species.ConclusionsSince all precautions have been taken to minimize taxon numbers, it is safe to affirm than the number of fish parasites is at least ten times the number of fish species in coral reefs, for species of similar size or larger than the species in the four families studied; this is a major improvement to our estimate of biodiversity in coral reefs. Our results suggest that extinction of a coral reef fish species would eventually result in the coextinction of at least ten species of parasites.

Eight new species of Siphoderina Manter, 1934 (Digenea, Cryptogonimidae) infecting Lutjanidae and Haemulidae (Perciformes) off Australia

We report nine species, eight of which are new, of cryptogonimids belonging to Siphoderina Manter, 1934 from the intestine and pyloric caeca of five species of Lutjanidae (Lutjanus adetii, L. argentimaculatus, L. carponotatus, L. fulviflamma and L. russelli) and one species of Haemulidae (Plectorhinchus gibbosus) recovered from Heron and Lizard Islands off the Great Barrier Reef, Moreton Bay and Ningaloo Reef in Western Australia. We also report the metacercariae of two species from an atherinid fish, Atherinomorus capricornensis, from near Heron Island. Morphological analysis of the species reported here was augmented by DNA sequence analyses utilizing data from the internal transcribed spacers (ITS) 1 and 2, large subunit (LSU) and 5.8S nuclear ribosomal DNA to explore the integrity of the species and their biogeographic distributions. The analysis found strong support for the integrity of Siphoderina and found that it is the sister-taxon to Beluesca Miller et Cribb, 2007. Sequencing included multiple replicates and no intraspecific variation was observed between any of the taxa over the rDNA regions examined. Sequence data from the ITS and LSU regions were analysed with that of species of Beluesca, Caulanus Miller et Cribb, 2007, Chelediadema Miller et Cribb, 2007, Latuterus Miller et Cribb, 2007, Neometadena Hafeezullah et Siddiqi, 1970 and Retrovarium Miller et Cribb, 2007 which all also infect lutjanids or haemulids. Some closely related species of Siphoderina infect only distantly related fishes among the haemulids and lutjanids whereas others form clusters in association with clusters of closely related lutjanids. This pattern suggests a history of some co-evolutionary divergence together with significant host switching. Pseudallacanthochasmus Velasquez, 1961 is considered a synonym of Siphoderina and the new combinations S. grandispinus (Velasquez, 1961) n. comb. and S. magnivesiculum (Gaevskaya et Aljoshkina, 1985) n. comb. are proposed. As a result of the new species described here and these new combinations, Siphoderina now contains 43 species, making it by far the largest genus of the Cryptogonimidae.

Brain infecting kudoids of Australia's coral reefs, including a description of Kudoa lemniscati n. sp. (Myxosporea: Kudoidae) from Lutjanus lemniscatus (Perciformes: Lutjanidae) off Ningaloo Reef, Western Australia

A survey of the myxosporean fauna of Australian marine fishes revealed the presence of a number of putative species of Kudoidae (Multivalvulida) forming pseudocysts between the outer meningeal layer and the outer surface of the brains of the lutjanids Caesio cuning, Lutjanus carponotatus, Lutjanus ehrenbergii and Lutjanus fulviflamma and the mugilid Liza vaigiensis from Lizard Island on the Great Barrier Reef, Australia and Lutjanus lemniscatus off Ningaloo Reef, Western Australia. Morphometric data combined with Bayesian inference and maximum likelihood analyses of small subunit (SSU) and large subunit (LSU) ribosomal DNA (rDNA) was used for species identification and to explore relationships among these taxa. The brain-infecting taxa examined here formed a well-supported clade to the exclusion of non-brain infecting species in the phylogenetic analyses. The combined diagnostic approach identified an undescribed taxon, Kudoa lemniscati n. sp., from the brain of L. lemniscatus (Perciformes: Lutjanidae) off Ningaloo Reef, Western Australia, which we describe and characterise here. K. lemniscati n. sp. can be distinguished from all other species of Kudoa based on the combination of the distinct tropism for forming pseudocysts in the brain tissue, spores with 7 or 8 equal shell valves and 7 or 8 polar capsules, spore size and the differences in the SSU and LSU rDNA sequence data relative to other kudoids. Kudoa chaetodoni was found in the lutjanids C. cuning and L. carponotatus, expanding the known host range for this species to include chaetodontids and lutjanids. L. ehrenbergii and L. fulviflamma were infected with Kudoa lethrini off Lizard Island, a parasite previously known only from lethrinids. Specimens putatively identified as Kudoa yasunagai from Liza vaigiensis and Lutjanus ehrenbergii were morphologically similar and genetically identical over the SSU rDNA dataset to previously reported specimens, but differed by 4 to 11 nucleotides over the LSU dataset from the remaining isolates examined here. While these data are not definitive, they suggest the presence of a K. yasunagai complex.

Cryptic species of Euryakaina n. g. (Digenea: Cryptogonimidae) from sympatric lutjanids in the Indo-West Pacific

A survey of the endohelminth fauna of Indo-West Pacific Lutjanidae (Perciformes) revealed the presence of the species Siphoderina manilensis (Velasquez, 1961) Miller & Cribb, 2008 and S. marina (Hafeezullah & Siddiqi, 1970) Miller & Cribb, 2008 in seven Lutjanus spp. from sites off the Great Barrier Reef, the Maldives, New Caledonia and Ningaloo Reef, Western Australia. A combination of morphological and ribosomal DNA analyses of these cryptogonimids prompted the transfer of these taxa to a new genus, Euryakaina n. g., as E. manilensis n. comb. and E. marina n. comb., based on comparative analysis with other cryptogonimid taxa. Euryakaina n. g. is distinguished from all other cryptogonimid genera by the combination of a fusiform body, the few relatively small, widely spaced oral spines (sometimes absent), a highly lobed ovary, opposite to slightly oblique testes, vitelline follicles that extend from the anterior margin of the testes to slightly posterior to the intestinal bifurcation, and an excretory vesicle that bifurcates dorsal to the ovary and reunites briefly slightly posterior to the intestinal bifurcation. Morphometric analysis of these taxa alone suggests they should be reduced to synonymy, but DNA sequence analyses and ecological niche partitioning provide evidence that they form a cryptic species complex in sympatric lutjanids in the Indo-West Pacific. The secondary structure of the ITS2 rDNA for species of Euryakaina was also modelled and analysed for the presences of compensatory base changes (CBCs) or hemi-CBCs in order to explore the usefulness of these changes as a tool to help elucidate the taxonomy of this complex system. We also report what we interpret here as intraspecific variation in the ITS2 rDNA between individuals of E. manilensis from Lutjanus vitta recovered off the Great Barrier Reef and New Caledonia.

Adlardia novaecaledoniae n. g., n. sp. (Digenea: Cryptogonimidae) from the fork-tailed threadfin bream Nemipterus furcosus (Val.) (Perciformes: Nemipteridae) off New Caledonia.

Adlardianovaecaledoniae n. g., n. sp. (Digenea: Cryptogonimidae) is described from the fish Nemipterus furcosus (Val.) (Perciformes: Nemipteridae) from off New Caledonia (South Pacific). Adlardia n. g. is distinguished from all other cryptogonimid genera by the combination of an elongate body, the presence of oral spines, intestinal caeca that open via ani at the posterior end of the body, a highly lobed ovary, oblique testes that are located in the mid-hindbody, vitelline follicles that extend from midway between the testes and ovary to midway between the ovary and ventral sucker, and an excretory vesicle that bifurcates dorsal to the ovary and reunites immediately anterior to the pharynx. A.xa0novaecaledoniae n. sp. is the only cryptogonimid that has been reported with an excretory vesicle that reunites anterior to the pharynx. Siphoderina elongata (Gu & Shen, 1979) Miller & Cribb, 2008 is transferred to Adlardia as A.xa0elongata (Gu & Shen, 1979) n. comb. based on morphological and ecological (host group) agreement with A.xa0novaecaledoniae. Bayesian inference analysis of LSU rDNA revealed that A.xa0novaecaledoniae nested well within a clade containing cryptogonimid taxa known almost exclusively from haemulid and lutjanid fishes, suggesting that host-switching between teleosts of the Haemuloidea, Lutjanoidea and Sparoidea may have been common in the evolutionary history of this system.RésuméAdlardianovaecaledoniae n. g., n. sp. (Digenea: Cryptogonimidae) est décrit du poisson Nemipterus furcosus (Val.) (Perciformes: Nemipteridae) de Nouvelle-Calédonie (Pacifique Sud). Adlardia n. g. est distingué de tous les autres genres de Cryptogonimidae par la combinaison d’un corps allongé, la présence d’épines orales, des caeca intestinaux qui s’ouvrent par des anus dans la partie postérieure du corps, un ovaire très lobé, des testicules obliques qui sont situés au centre de la partie postérieure du corps, des follicules vitellins qui s’étendent d’entre les testicules et l’ovaire jusqu’entre l’ovaire et la ventouse ventrale et une vésicule excrétrice qui bifurque dorsalement par rapport à l’ovaire et se réunit juste en avant du pharynx. A.xa0novaecaledoniae n. sp. est le seul Cryptogonimidae qui a été décrit avec une vésicule excrétrice qui se réunit juste en avant du pharynx. Siphoderina elongata (Gu & Shen, 1979) Miller & Cribb, 2008 est transféré vers Adlardia comme A.xa0elongata (Gu & Shen, 1979) n. comb. sur la base de ressemblances morphologiques et écologiques (groupe hôte) avec A.xa0novaecaledoniae. Une analyse d’inférence bayésienne de l’ADNr LSU a révélé que A.xa0novaecaledoniae trouvait sa place dans un clade comprenant des taxons de Cryptogonimidae connus presque exclusivement de poissons Haemulidae et de Lutjanidae, ce qui suggère que des changements d’hôtes entre des téléostéens Haemuloidea, Lutjanoidea et Sparoidea ont pu être communs dans l’histoire évolutive du système.

Varialvus gen. nov. (Digenea, Cryptogonimidae), from species of Lutjanidae (Perciformes) off the Great Barrier Reef, New Caledonia and the Maldives

A survey of the cryptogonimid trematode fauna infecting Indo-West Pacific Lutjanidae (Perciformes) revealed the presence of four new species whose morphological and genetic differences relative to all other known cryptogonimids warrants the proposal of a new genus, Varialvus gen. nov. Species of this new genus were recovered from sites off Heron and Lizard Islands on the Great Barrier Reef, Australia, New Caledonia and Rasdhoo Atoll, Maldives. Varialvus gen. nov. is distinguished from all other cryptogonimid genera by the combination of a fusiform to oval body, the relatively small number of large oral spines, a median ovary which is relatively condensed and highly lobed, opposite to slightly oblique testes, uterine loops that are restricted to the hindbody and extend well posterior to the testes, and vitelline follicles that are mainly in the forebody but may extend from the anterior margin of the ovary to anterior to the intestinal bifurcation. Bayesian inference analysis of partial large subunit (LSU) rDNA sequence data for these species revealed that they formed a monophyletic clade, despite V. charadrus sp. nov. having a distinctly muscular gonotyl, which based on morphological characters alone may have warranted placement in a separate genus in the absence of DNA sequence data. At least one species of Varialvus gen. nov. is apparently widespread in the Indo-West Pacific. Three species, V. lacertus sp. nov., V. jenae sp. nov. and V. angustus sp. nov. have each been found at only one locality, but V. charadrus sp. nov. was recovered from lutjanids off the Great Barrier Reef, New Caledonia and the Maldives, demonstrating a biogeographic range of at least 10,000 kilometres. Siphoderina lutjani (Saoud, Ramadan et Al Kawari, 1988) Miller et Cribb, 2008 is transferred here as V. lutjani (Saoud, Ramadan et Al Kawari, 1988) n. comb. based on morphological and host group agreement with species of Varialvus gen. nov.

Gynichthys diakidnus n. g., n. sp. (Digenea: Cryptogonimidae) from the grunt Plectorhinchus gibbosus (Lacépède, 1802) (Perciformes: Haemulidae) off the Great Barrier Reef, Australia

Gynichthys diakidnus n. g., n. sp. (Digenea: Cryptogonimidae) is described from the fish Plectorhinchus gibbosus (Lacépède) (Perciformes: Haemulidae) off Heron and Lizard Islands on the Great Barrier Reef, Australia. The monotypic Gynichthys n. g. is distinguished from all other cryptogonimid genera by the combination of a fusiform body, the lack of oral spines, a forebody that occupies approximately half or more of the body length, a deeply lobed ovary, opposite to slightly oblique testes, a seminal vesicle that is confined mainly in the forebody and the presence of multiple gonotyls in the form of two small slightly muscular pores or pseudosucker-like structures in the mid-line well anterior to the ventral sucker. Bayesian inference analysis of LSU rDNA data revealed that G. diakidnus n. sp. grouped relatively distant to species of the cryptogonimid genus Oligogonotylus Watson, 1976, which also have multiple gonotyls, suggesting that the presence of multiple gonotyls is homoplasious and has thus at least evolved twice in the family. The secondary structure of the internal transcribed spacer 2 (ITS2) rDNA region was inferred for G. diakidnus using minimum free energy and homology modelling algorithms. A four helix model was inferred with helices I and IV being relatively short (<30 nucleotides) and helix three being the longest; this structure is homologous with that observed for other digeneans and eukaryotes in general.

Henneguya mauritaniensis n. sp. (Myxozoa) from the arterial bulb of Pagrus caeruleostictus (Valenciennes, 1830) off Mauritania

We describe a new species of myxozoan, Henneguya mauritaniensis n. sp., extracted from the arterial bulb of the bluespotted seabream, Pagrus caeruleostictus (Valenciennes, 1830), collected in Mauritanian waters. Out of the 209 individuals examined, 30.1xa0% were infected with this new taxon. Spore total length ranged from 15.0 to 20.5xa0μm with a mean of 17.9xa0μm. The two polar capsules were equal in size, and pyriform and caudal appendages joined until mid-length. Morphometric analysis revealed significant differences between H. mauritaniensis n. sp. and morphologically similar species from this region as well as congeners known from other sparid hosts. Phylogenetic analysis of 18xa0S rDNA indicated that this new species is closely related to Henneguya pagri, reported recently from Pagrus major off Japan. Bayesian inference and maximum likelihood analyses of the 18xa0S rDNA dataset also revealed that species of marine Henneguya reported forming pseudocysts in the hearts of their fish hosts were closely related. Histological analysis of the H. mauritaniensis n. sp. pseudocysts embedded in the arterial bulb of P. caeruleostictus suggests that these parasites may cause considerable pathology, which may impact negatively on the health of the fish host. Finally, we discussed the importance of a combination of morphological and molecular analysis for species description because of high variability in size within the same taxa.