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Morphological disparity despite genetic similarity; new species of Lobosorchis Miller & Cribb, 2005 (Digenea: Cryptogonimidae) from the Great Barrier Reef and the Maldives
Abstract
Examination of the humpback red snapper, Lutjanus gibbus (Perciformes: Lutjanidae), from Lizard Island off the Great Barrier Reef and Rasdhoo Atoll, Maldives revealed the presence of a new species of Lobosorchis (Digenea: Cryptogonimidae), L. polygongylus n. sp. Lobosorchis polygongylus n. sp. is distinguished from the typeand only other species, L. tibaldiae by the combination of body size, oral spine number (60–81 in L. polygongylus, 47–56 in L. tibaldiae) and number of testes (13–25 in L. polygongylus, 9 in L. tibaldiae). Bayesian inference analysis using data from the internal transcribed spacers 1 and 2 (ITS1 and ITS2), 5.8S and the large subunit (LSU) nuclear ribosomal DNA of L. polygongylus, L. tibaldiae and species of Beluesca, Caulanus, Chelediadema, Neometadena, Latuterus, Retrovarium and Siphoderina was performed to explore phylogenetic relationships of species of Lobosorchis with other cryptogonimid taxa. Despite the significant morphological differences between Lobosorchis polygongylus and L. tibaldiae, these two species differed consistently by only 5 base pairs (bp) over the entire ITS region (3 bp in ITS1, 0 bp in 5.8S and 2 bp in ITS2) and 1 bp in the LSU rDNA regions examined. The ITS2 rDNA region was sequenced from metacercariae obtained from the fins, flesh or body cavities of a number of fishes belonging to the Blenniidae, Pomacentridae and Tetraodontidae and analysed using minimum evolution analysis with L. polygongylus and L. tibaldiae. This revealed the presence of two additional genotypes (putative Lobosorchis sp. A and B), which consistently differed from L. polygongylus by 1 and 4 bp, L. tibaldiae by 1 and 4 bp and from each other by 3 bp over the ITS2 dataset. Although these genetic differences are relatively small, when evaluated in light of the differences observed between L. polygongylus and L. tibaldiae (which are morphologically quite distinct) and differences seen in other congeneric cryptogonimid taxa, the ITS2 rDNA data alone suggest that at least two more species of Lobosorchis are present at Lizard Island. These data also suggest that the ITS2 rDNA region alone is suitable for resolving operational taxonomic units (OTUs) at the species level within the Cryptogonimidae based on what was observed in this and other cryptogonimid systems. A morphological description of metacercariae of L. tibaldiae obtained from two species of Pomacentridae at Heron Island, off the Great Barrier Reef is also provided.
... We augment our morphologically based taxonomic approach to the taxon recovered here with an analysis of genetic data from the large subunit (LSU) nuclear ribosomal DNA region with the aim of exploring the integrity of the new species and its phylogenetic relationships with other cryptogonimid taxa. The LSU rDNA data obtained for the specimens reported here were aligned with data available from previously reported cryptogonimids (Miller & Cribb, 2007a, b, c, 2008Miller et al., 2009;Olson et al., 2003;Razo-Mendivil et al., 2008) and analysed using Bayesian inference analysis to explore intergeneric relationships between these species. In addition, we infer the secondary structure of the internal transcribed spacer 2 (ITS2) rDNA region to explore whether the structure is homologous with that reported for other digeneans and eukaryotes in general. ...
... The LSU rDNA region for Gynichthys diakidnus was aligned with data reported for species of the cryptogonimid genera Beluesca Miller & Cribb, 2007, Caecincola Marshall & Gilbert, 1905, Caulanus Miller & Cribb, 2007, Chelediadema Miller & Cribb, 2007, Latuterus Miller & Cribb, 2007, Lobosorchis Miller & Cribb, 2005, Mitotrema Manter, 1963, Neometadena Hafeezullah & Siddiqi, 1970, Oligogonotylus Watson, 1976, Retrovarium Miller & Cribb, 2007, Siphodera Linton, 1910and Siphoderina Manter, 1934by Miller & Cribb (2007a, b, c, 2008, Miller et al. (2009), Olson et al. (2003 and Razo-Mendivil et al. (2008) for comparative purposes and to explore levels of intergeneric variation. The LSU rDNA fragments for species of Oligogonotylus deposited on GenBank by Razo-Mendivil et al. (2008) overlap the LSU region for the remainder of the cryptogonimid taxa listed above by only approximately 440 bp, so two LSU alignments were constructed for analysis. ...
... Gynichthys diakidnus n. sp. is apparently widely distributed on the Great Barrier Reef, as it was recovered from localities in the northern and southern regions that are separated by over 1,100 kilometres. Given that Plectorhinchus gibbosus occurs widely in the Indo-West Pacific, it is possible that G. diakidnus is also distributed widely throughout the Indo-West Pacific, particularly in view of the wide biogeographical distributions reported recently for other cryptogonimid taxa in this region (Miller & Cribb, 2007a, c;Miller et al., 2009). ...
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.
... (Bell et al., 2001), and one to four base pair divergent between four species of Lobosorchis spp. (Miller et al., 2009). There are also cases reported where species have identical ITS2 regions but substantial differences in the mitochondrial gene cytochrome c oxidase subunit 1 (CO1) and the differentiation was supported by morphological disparities (Blair et al., 1997). ...
... There are also cases reported where species have identical ITS2 regions but substantial differences in the mitochondrial gene cytochrome c oxidase subunit 1 (CO1) and the differentiation was supported by morphological disparities (Blair et al., 1997). In contrast, there are numerous studies in which low numbers of differences are reported but for which there are insufficient morphological and biological differences to support the recognition of separate species (Miller et al., 2009;Hunter et al., 2010;Downie et al., 2011). Here, we consider the variation of a single base pair within each morphospecies as intraspecific variation as there was an absence of morphological, host and geographical distribution differences between the haplotypes. ...
A total of 2,868 individuals of 47 species of chaetodontids were examined for faustulids at seven major localities in the Tropical Indo-West Pacific (TIWP). Combined morphological and molecular analyses allowed us to describe Paradiscogaster oxleyi n. sp. from three localities in the TIWP and in three host species, Chaetodon lunulatus Quoy & Gaimard (type-host), C. ornatissimus Cuvier and C. meyeri Bloch & Schneider. Molecular analysis of the ITS2 region of rDNA from two host species and three localities supports the morphology-based conclusion that P. oxleyi n. sp. is the same species at the three localities. Paradiscogaster flindersi Bray, Cribb & Barker, 1994 is reported from three new localities in the TIWP and is now known from 13 chaetodontid species. Sequences from samples consistent with P. flindersi differed from those from P. oxleyi n. sp. in 11-12 base pairs. The host ranges of the two species overlap broadly. Neither species was found in French Polynesia but both were found at Swain Reefs on the Great Barrier Reef. Only one of the two species was found at each of the five other sites. Both species occur almost exclusively in specialist corallivores allowing the inference that the metacercariae occur in corals. Finally, a key to the species of Paradiscogaster is provided.
... Aiken et al. (2007) showed that the aporocotylid Cardicola forsteri Cribb, Daintith & Munday, 2000 has an essentially cosmopolitan distribution in its mobile scombrid hosts. For trematodes of site-attached coral reef fishes, ranges of at least 6,000 km have been reported for species of Apocreadiidae, Cryptogonimidae, Lecithasteridae and Lepocreadiidae (Chambers and Cribb 2006;Lo et al. 2001;Miller et al. 2010;Miller and Cribb 2007a;Miller and Cribb 2007b;Miller et al. 2009). These findings are further relatable to other comparisons between the GBR and French Polynesia. ...
... Despite their morphological similarity, these four species still differed by no fewer than 7 and as many as 28 bases. These levels exceed those found between some combinations of aporocotylids, cryptogonimids and transversotrematids considered distinct species on the basis of a range of morphological and biological characters in addition to the molecular distinctions (Hunter and Cribb 2012;Miller et al. 2009;Nolan and Cribb 2006). Overall, the inter-specific divergence in the ITS2 rRNA of 10 to 42 bp (4-16 %) difference for Neidhartia species and 2 to 57 bp (3-21 %) difference for Prosorhynchus species and inter-generic divergence of 42 to 55 base pairs (17-21 %) differences is broadly consistent with the levels of variation that have been reported previously. ...
We examined four species of Plectropomus Oken, 1817 (Serranidae: Epinephelinae), Plectropomus areolatus (Rüppell), Plectropomus laevis (Lacepède), Plectropomus leopardus (Lacepède) and Plectropomus maculatus (Bloch) from sites off Heron Island and Lizard Island on the Great Barrier Reef, Australia (GBR), and the Gambier Islands, French Polynesia. Three new species of Neidhartia Nagaty, 1937, five new species of Prosorhynchus Odhner, 1905, and one previously described species, Prosorhynchus freitasi Nagaty, 1937, are characterised. The three species of Neidhartia, Neidhartia haywardi n. sp., Neidhartia plectropomi n. sp. and Neidhartia tyleri n. sp. are readily distinguishable morphologically. Two of the six species of Prosorhynchus (Prosorhynchus lesteri n. sp. and Prosorhynchus wrightae n. sp.) are easily distinguished from their other congeners by morphology but the other four species (P. freitasi, Prosorhynchus heronensis n. sp., Prosorhynchus munozae n. sp. and Prosorhynchus plectropomi n. sp.) are generally similar in morphology and were only distinguished initially by comparing their ITS2 rRNA sequences. Three additional taxa, one from the GBR and two from French Polynesia, were recognised as distinct on the basis that their ITS2 rRNA sequences differed from those of the new taxa described here; these species remain unnamed for the present. Inter-specific divergence observed within these genera in the ITS2 rRNA ranged from 10 to 42 base pairs (4-16 %) for species of Neidhartia and 2-57 base pairs (3-21 %) for species of Prosorhynchus. Inter-generic divergences were 42-55 base pairs (17-21 %). No intraspecific variation in the ITS2 rRNA region was observed for any of the six species for which multiple sequence replicates were obtained. Phylogenetic analysis of 12 operational taxa from Plectropomus together with sequences of three other species from epinepheline serranids demonstrated that Neidhartia and Prosorhynchus were reciprocally monophyletic with the exception that P. wrightae n. sp. fell either within or basal to the Neidhartia species. The richness of bucephalids in species of Plectropomus appears to be exceptional within the Serranidae relative to that observed in other serranid genera in the tropical Indo-West Pacific.
... This suggests some host preference by these parasites, as observed for other cryptogonimid genera parasitising marine fishes of the families Lutjanidae and Haemulidae (e.g. Cribb 2005, 2007a, b;2008b;Miller et al. 2009Miller et al. , 2010. However, only a few species of the large genus Pimelodella have been examined, indicating that further research is needed to reach more definitive conclusions. ...
... A similar situation is described for Pseudacanthostomum panamense Caballero, Bravo-Hollis & Grocott, 1953 (oral spine length 28-59 lm) by Scholz et al. (1999), in the case of 14 specimens measured from three different hosts. In species with a single fish host, the variation in the size of the oral spines is generally lower, as can be observed in P. carapo (28-47 lm in length), P. virescens (16-28 lm) and several species of Siphoderina Manter, 1934 (see Miller and Cribb, 2008b), but there are exceptions, as in the cases of S. subuterus Miller & Cribb, 2008, Acanthostomoides apophalliformis Szidat, 1956and Lobosorchis polygongylus Miller, Downie & Cribb, 2009(Miller & Cribb, 2008bMiller et al., 2009;Ostrowski de Núñez et al., 1999), among others, in which the maximum length of the spines is at least twice the length of the minimum. ...
A new species of cryptogonimid belonging to the genus Parspina Pearse, 1920 is described from the intestine of Pimelodella gracilis (Valenciennes) in the Paraná River basin, Argentina. Parspina pimelodellae n. sp. is characterised by having: (i) a body length/width ratio of 1:3.6-5.3 at the level of the ventral sucker; (ii) 21 oral spines; (iii) an oral sucker larger than the ventral sucker, with a sucker width ratio of 1:0.6-0.7; (iv) a postcaecal region of 16-19% of the body-length; (v) a compact, transversely elongate ovary, anterior to and well separated from the testes; (vi) small, branched vitelline follicles, extending from the level of the ventral sucker to the anterior margin of the ovary; and (vii) a large seminal vesicle situated posterodorsal to the ventral sucker. A key to the species of Parspina is presented.
... Cryptogonimid species reported from Indo-Pacific Lutjanidae exhibit striking patterns of biogeographical distribution; some species have been reported at only a single locality whereas others have been found at localities separated by over 15,000 km. For example, four species, Caulanus thomasi, Lobosorchis polygongylus Miller, Downie & Cribb, 2009, Retrovarium brooksi Miller & Cribb, 2007and R. sablae Miller & Cribb, 2007 Hafeezullah & Siddiqi, 1970 and other cryptogonimid taxa based on Bayesian inference and maximum likelihood analyses of the concatenated ITS2 and partial LSU dataset. Posterior probabilities and bootstrap support values are indicated at the nodes (respectively) with values \ 50% indicated with an asterisk that these species have biogeographical ranges of at least 9,000 km (Miller & Cribb, 2007a, b;. ...
A survey of the trematode fauna of lutjanid fishes off the east coast of Queensland (QLD), Australia revealed the presence of two species of Neometadena Hafeezullah & Siddiqi, 1970 (Digenea: Cryptogonimidae). Neometadena paucispina n. sp. is described from the intestine and pyloric caeca of Lutjanus fulviflamma (Forsskål) and L. russellii (Bleeker) from Moreton Bay, in southeast QLD. Specimens of the type- and only other species, N. ovata (Yamaguti, 1952) Miller & Cribb, 2008, were recovered from L. carponotatus (Richardson), L. fulviflamma, L. fulvus (Forster), L. russellii, and L. vitta (Quoy & Gaimard) off Lizard Island, on the northern Great Barrier Reef (GBR). Neometadena paucispina is distinguished from N. ovata in having fewer oral spines (55-65 vs 67-80). Alignment of novel molecular data for these two taxa revealed that they differ consistently by 13 nucleotides (1.5%) over the partial large subunit (LSU), 34 nucleotides (6.6%) over the internal transcribed spacer 1 (ITS1), 0 nucleotides over the 5.8S, and 21 nucleotides (7.3%) over the ITS2 rDNA regions. Despite relatively large samples of L. carponotatus, L. fulviflamma and L. russellii from three distinct locations along the east coast of QLD (i.e. Moreton Bay in the south, Heron Island in central QLD and Lizard Island in northern QLD), these two species have been found at only one site each with neither species at Heron Island. These distributions are discussed in the context of the wide distribution of other cryptogonomid species in the same hosts elsewhere in the Indo-West Pacific.
... Matches between the two subsets of sequences allowed some life cycles to be resolved; the large number of 'orphan' sequences also means that further host sampling will be necessary to complete the remaining life cycles (Jensen & Bullard, 2010). A similar effort is under way to match sequences from metacercariae and adult trematodes of fishes from the Great Barrier Reef (Miller et al., 2009;Downie & Cribb, 2011;T. Cribb, pers. ...
Many helminth taxa have complex life cycles, involving different life stages infecting different host species in a particular order to complete a single generation. Although the broad outlines of these cycles are known for any higher taxon, the details (morphology and biology of juvenile stages, specific identity of intermediate hosts) are generally unknown for particular species. In this review, we first provide quantitative evidence that although new helminth species are described annually at an increasing rate, the parallel effort to elucidate life cycles has become disproportionately smaller over time. We then review the use of morphological matching, experimental infections and genetic matching as approaches to elucidate helminth life cycles. Next we discuss the various research areas or disciplines that could benefit from a solid knowledge of particular life cycles, including integrative taxonomy, the study of parasite evolution, food-web ecology, and the management and control of parasitic diseases. Finally, we end by proposing changes to the requirements for new species descriptions and further large-scale attempts to genetically match adult and juvenile helminth stages in regional faunas, as part of a plea to parasitologists to bring parasite life-cycle studies back into mainstream research.
... This study was conducted to address a number of issues: the number of species of transversotrematids genetically and morphologically similar to T. licinum in the region; the geographic distribution of these species; and the host distribution of the complex. The genetic marker used for this study was the second internal transcribed spacer region (ITS2) of the ribosomal gene complex which has been widely used to explore taxonomic issues relating to closely related trematodes (Anderson & Barker 1998;Blair et al. 1996;Galazzo et al. 2002;Hall & Cribb 2008;Miller et al. 2010;Miller et al. 2009;Nolan & Cribb 2005). ...
Transversotrema licinum Manter, 1970 was described from two species of fishes from Moreton Bay, Queensland, and subsequently reported from 13 further species from six families in the Indo-West Pacific region. This study records specimens morphologically similar to T. licinum from 48 fish species from 11 families. A combined analysis of the second internal transcribed spacer region (ITS2) of ribosomal DNA and morphological data revealed a complex of at least 15 species and from these data ten new species of Transversotrema Witenberg, 1944 are described here. T. licinum sensu stricto is characterised in terms of morphology, distinct genotype, wide host distribution (Kyphosidae, Lutjanidae, Monodactylidae, Mugilidae, Pomacentridae and Sparidae) and, at present, is known only in Moreton Bay. The following new species are proposed: T. atkinsoni n. sp. from nemipterids from Heron Island (southern GBR) and Ningaloo Reef (Western Australia);T. borboleta n. sp. from chaetodontids and lutjanines (Lutjanidae) from Lizard Island and Heron Island; T. cardinalis n. sp. from lutjanines and a haemulid from Lizard Island; T. carmenae n. sp. from nemipterids from Lizard Island; T. damsella n. sp. from pomacentrids, a labrid and a mugilid from Lizard Island; T. espanola n. sp. from lutjanines from Heron and Lizard Islands; T. fusilieri n. sp. from caesionines (Lutjanidae) from Lizard Island; T. manteri n. sp. from caesionines from Lizard Island and Ningaloo Reef; T. nova n. sp. from a nemipterid from New Caledonia; and T. witenbergi n. sp. from caesionines from Heron Island. Transversotrema borboleta n. sp. is itself probably a complex of at least three closely related species but these are not yet sufficiently well delineated to allow separate descriptions. Four putative species referred to as Species A-D recognised from molecular analysis have not been described because of insufficient data. Most species are evidently strongly restricted to families or subfamilies of fishes. Only T. licinum appears to be genuinely euryxenic. Transversotrema borboleta infects chaetodontids and lutjanids but the nature of the distribution may be an indication that it represents a species complex. Most of the species appear to have restricted ranges, being absent from susceptible host species at some localities.
... . Efforts are underway to connect the juvenile stages of helminths in one host to their morphologically distinct adults in different host species using molecular markers (e.g., trematodes on the Great Barrier Reef:Miller et al., 2009; Downie and Cribb, 2011; cestodes in the northern Gulf of Mexico: Jensen and Bullard, 2010), but these are far from being completed. The accumulation in online databases of sequences from parasite life stages found in different host species will increasingly allow life cycles to be resolved that way.Our ignorance of the life cycles of marine parasites has implications for our understanding of their roles in ecosystems and their transmission pathways. ...
Despite their very different historical origins as scientific disciplines, parasitology and marine ecology have already combined successfully to make important contributions to our understanding of the functioning of natural ecosystems. For example, robust assessments of the contribution of parasites to ecosystem biomass and energetics, and of their impact on community-wide biodiversity and food web structure, have all been made for the first time in marine systems. Nevertheless, for the marriage between parasitology and marine ecology to remain fruitful, several challenges must first be overcome. We discuss seven such challenges on the road to a greater synergy between these disciplines: (1) Raising awareness of parasitism as an ecological force by increasing the proportion of articles about parasites and diseases in marine ecology journals; (2) Making greater use of theory and conceptual frameworks from marine ecology to guide parasitological research; (3) Speeding up or at least maintaining the current rate at which marine parasites are found and described; (4) Elucidating a greater proportion of life cycles in all major groups of marine parasites; (5) Increasing the number of host-parasite model systems on which our knowledge is based; (6) Extending parasitological research offshore and into ocean depths; (7) Developing, as needed, new epidemiological theory and transmission models for the marine environment. None of these challenges is insurmountable, and addressing just a few of them should guarantee that parasitology and marine ecology will continue to join forces and make further substantial contributions.
... Bayesian inference and maximum likelihood analyses of the ITS and LSU ribosomal RNA of S. gurukun and S. raritas unambiguously show that these species are closely related. These two species differed by only 22 bp (2.2% sequence divergence) in the ITS and by 15 bp (1.7%) in the LSU rDNA regions examined, a level of variation similar to the interspecific variation observed among other cryptogonimid taxa (Miller & Cribb, 2007a, c, d, 2008aMiller et al., 2009cMiller et al., , 2010a. Miller & Cribb (2007a, 2008b stressed the importance of using a combination of morphological and ecological (host preference) characteristics in taxonomic keys to aid in the identification of cryptogonimid species and genera. ...
A survey of Indo-Pacific lutjanids of the subfamily Caesioninae revealed the presence of Siphodera gurukun Machida, 1910 and two new cryptogonimid taxa from off Heron and Lizard Islands on the Great Barrier Reef, Australia, Ningaloo Reef, Western Australia and Rasdhoo Atoll, Maldives. A combined morphological and genetic characterisation of these species shows that they form a clade distinct from the type-species of Siphodera Linton, 1910, S. vinaledwardsii (Linton, 1901), and warrants the proposal of a new genus. Here we propose Siphomutabilus n. g. and transfer Siphodera gurukun Machida, 1986 as the type-species, Siphomutabilus gurukun (Machida, 1986) n. comb. Siphodera aegyptensis Hassanine & Gibson, 2005 is transferred to Siphomutabilus as S. aegyptensis (Hassanine & Gibson, 2005) n. comb. based on morphological and ecological similarities. Siphomutabilus raritas n. sp. is described from Caesio cuning (Bloch) off Lizard Island and S. bitesticulatus n. sp. is described from Pterocaesio marri Schultz off Heron Island. The two new species are unique in that they have two testes, making their morphology broadly consistent with that of Metadena Linton, 1910, yet the molecular analyses conducted here indicates that they are unequivocally united with Siphomutabilus gurukun (which has multiple testes) to the exclusion of Metadena lutiani (Yamaguti, 1942), which was sequenced here. The dramatic phenotypic plasticity observed among such closely related species of Siphomutabilus suggests a secondary modification of what is generally considered a robust generic diagnostic character within this and other digenean families, highlighting the need for a combined morphological and molecular diagnostic approach when characterising these taxa. Siphodera Linton, 1910 is amended to include just two species, the type-species S. vinaledwardsii (Linton, 1901) Linton, 1910 and S. cirrhiti Yamaguti, 1970, which are distinguished by their lack of oral spines and multiple testes that are primarily extracaecal. Siphodera ghanensis Fischthal & Thomas, 1968 is considered a species incertae sedis here based on significant morphological and ecological differences compared with species of Siphodera and Siphomutabilus n. g.
... (Strigeidae) (Bell et al., 2001), one to four base differences between combinations of four Lobosorchis spp. (Cryptogonimidae) (Miller et al., 2009), two base differences between two didymozoid species (Anderson & Barker, 1998) and two base differences between two Echinostoma spp. (Echinostomatidae) (Morgan & Blair, 1995). ...
Combined molecular and morphological data demonstrate the presence of two species of Symmetrovesicula Yamaguti, 1938 in chaetodontid fishes from Australian waters. A total of 2,462 individuals of 46 species of chaetodontid at eight localities were dissected. Analysis of the rDNA ITS2 revealed the presence of three genotypes, two separated by a single base difference and the third differed from the other two by 10-11 base differences. Subsequent morphological examination identified a number of variations that supported the presence of two species; however, we found no additional evidence to support the presence of a third species corresponding to the single base variation. Thus, we take the conservative approach of recognising two species of Symmetrovesicula within Australian waters, S. chaetodontis Yamaguti, 1938 from off Ningaloo Reef, Western Australia and S. gracilis n. sp. from off Ningaloo Reef, the Great Barrier Reef, Queensland and New Caledonia. Both species exhibit distinct restrictions to certain clades of chaetodontids.
Parasitological assessment of marine fishes at Sodwana Bay in the iSimangaliso Marine Protected Area on the east coast of South Africa revealed a new species of cryptogonimid trematode infecting the pyloric caeca of the Dory Snapper, Lutjanus fulviflamma (Forsskål) (Lutjanidae). The new species is morphologically consistent with the concept of the large genus Siphoderina Manter, 1934; its phylogenetic position within this genus was validated through molecular sequencing of the ITS2 and partial 28S ribosomal DNA sub-regions. We name this species Siphoderina nana n. sp. and comment on the current state of understanding for this genus of cryptogonimids.
A new cryptogonimid trematode, Siphoderina hustoni n. sp. , is reported, collected off Lizard Island, Queensland, Australia, from the Maori snapper Lutjanus rivulatus (Cuvier). The new species is moderately distinctive within the genus. It is larger and more elongate than most other species of Siphoderina Manter, 1934, has the shortest forebody of any, a relatively large ventral sucker, a long post-testicular zone, and is perhaps most recognisable for the substantial space in the midbody between the ventral sucker and ovary devoid of uterine coils and vitelline follicles, the former being restricted to largely posterior to the ovary and the latter distributed from the level of the anterior testis to the level of the ovary. In phylogenetic analyses of 28S ribosomal DNA, the new species resolved with the other nine species of Siphoderina for which sequence data are available, all of which are from Queensland waters and from lutjanid and haemulid fishes. Molecular barcode data were also generated, for the ITS2 ribosomal DNA and cox 1 mitochondrial DNA markers. The new species is the first cryptogonimid known from L . rivulatus and the first metazoan parasite reported from that fish in Australian waters.
We investigated diversity, infective situations, morphological features and phylogenetic relationships of the metacercariae in freshwater snails from Bangkok between March 2018 and February 2020. Crushing and dissection techniques were performed to explore the metacercariae in the snail hosts. Polymerase chain reaction was implemented to amplify the internal transcribed spacer 1 (ITS1), 5.8S ribosomal DNA and ITS2 regions of metacercarial DNA. A total of 3173 of all 21 707 snails showed infections with metacercariae, representing a relatively high infective prevalence (14.62%) compared to earlier research. All infected snails belonged to 14 species/subspecies. A group of viviparid snails exhibited the highest metacercarial infections (26.10–82.18%). We found metacercariae with seven morphological groups. Five of them can be stated as new records of the metacercariae in Thailand, indicating a broader spectrum of larval trematode diversity. Our phylogenetic assessments established that five of the seven morphological groups can be molecularly classified into different taxonomic levels of digenean trematodes. Echinostome A metacercariae revealed the highest infective prevalence (7.15%), and their sequence data were conspecific with a sequence of Echinostoma mekongki, which is a human intestinal fluke; this finding denotes the distribution and suggests epidemiological surveillance of this medically important fluke in Bangkok and adjacent areas. However, two groups of Opisthorchiata-like and renicolid metacercariae remain unclear as to their narrow taxonomic status, although their molecular properties were considered. For more understanding about trematode transmissions in ecosystems, both physical and biological factors may be further analysed to consider the factors that relate to and contribute to trematode infections.
New data have been obtained for three representatives of Exorchis ; Exorchis convictus sp. n., Exorchis oviformis and Exorchis sp., from fish in the East-Asian region. For the first time, based on combined sequences of the ITS2 rDNA region and the 28S rRNA gene, Exorchis is confirmed to belong Cryptogonimidae. Based on analysis of a mitochondrial marker ( cox 1), the ‘Japanese’ and ‘Russian’ haplogroups are identified for E. oviformis isolated from Silurus asotus . One specimen of E. oviformis obtained in Japan is identical to the ‘Russian’ haplotype. Haplotype patterns are also observed for metacercariae of Exorchis sp. from Tanakia lanceolata and Carassius sp. fish in Kyushu Island (Japan).
The superfamily Opisthorchioidea encompasses the families Cryptogonimidae, Opisthorchiidae and Heterophyidae. These parasites depend on the aquatic environment and include marine and freshwater species. Some species, such as Clonorchis sinensis and Opisthorchis viverrini, have a high impact on public health with millions of infected people worldwide and have thus been the object of many studies and tool developments. However, for many species, tools for identification and detection are scarce. Although morphological descriptions have been used and are still important, they are often not efficient on the immature stages of these parasites. Thus, during the past few decades, molecular approaches for parasite identification have become commonplace. These approaches are efficient, quick and reliable. Nonetheless, for some parasites of the superfamily Opisthorchioidea, reference genomic data are limited. This study reviews available genetic data and molecular tools for the identification and/or the detection of this superfamily. Molecular data on this superfamily are mostly based on mitochondrial and ribosomal gene sequence analyses, especially on the cytochrome c oxidase subunit 1 gene and internal transcribed spacer regions respectively.
The freshwater fish digenean Pseudosellacotyla lutzi (Freitas, 1941) Yamaguti, 1954 has had an unsettled taxonomic history, and has at various times been classified as a member of Nanophyetidae, Heterophyidae, Microphallidae, Faustulidae, and Cryptogonimidae. Nine individual specimens of the trahira, Hoplias malabaricus (Bloch, 1794), were sampled in the Paraná River basin, Paraná State, Brazil; twenty-two specimens of P. lutzi were collected. One specimen of P. lutzi was used to obtain a sequence of the domains D1-D3 of the 28S rRNA gene, and to perform a phylogenetic analysis to assess their position and classification within Plagiorchiida. The resulting tree unequivocally shows that the species, along with acanthostomines belong to the Cryptogonimidae, corroborating recent findings based on the morphology of the cercariae, and in the characteristics of the life cycle. In addition, the study of the ultrastructure of the tegumental spines through scanning electron microscopy (SEM), allowed us to characterize them as pectinate spines possessing 3 to 8 digitiform projections at their distal end, and extending from the anterior to the posterior extremity of the body. This study also provides the first molecular data for a cryptogonimid from South America.
Background
The Great Barrier Reef (GBR) is the world’s most iconic coral reef ecosystem, recognised internationally as a World Heritage Area of outstanding significance. Safeguarding the biodiversity of this universally important reef is a core legislative objective; however, ongoing cumulative impacts including widespread coral bleaching and other detrimental impacts have heightened conservation concerns for the future of the GBR.
Methods
Here we review the literature to report on processes threatening species on the GBR, the status of marine biodiversity, and evaluate the extent of species-level monitoring and reporting. We assess how many species are listed as threatened at a global scale and explore whether these same species are protected under national threatened species legislation. We conclude this review by providing future directions for protecting potentially endangered elements of biodiversity within the GBR.
Results
Most of the threats identified to be harming the diversity of marine life on the GBR over the last two–three decades remain to be effectively addressed and many are worsening. The inherent resilience of this globally significant coral reef ecosystem has been seriously compromised and various elements of the biological diversity for which it is renowned may be at risk of silent extinction. We show at least 136 of the 12,000+ animal species known to occur on the GBR (approximately 20% of the 700 species assessed by the IUCN) occur in elevated categories of threat ( Critically Endangered, Endangered or Vulnerable ) at a global scale. Despite the wider background level of threat for these 136 species, only 23 of them are listed as threatened under regional or national legislation.
Discussion
To adequately protect the biodiversity values of the GBR, it may be necessary to conduct further targeted species-level monitoring and reporting to complement ecosystem management approaches. Conducting a vigorous value of information analysis would provide the opportunity to evaluate what new and targeted information is necessary to support dynamic management and to safeguard both species and the ecosystem as a whole. Such an analysis would help decision-makers determine if further comprehensive biodiversity surveys are needed, especially for those species recognised to be facing elevated background levels of threat. If further monitoring is undertaken, it will be important to ensure it aligns with and informs the GBRMPA Outlook five-year reporting schedule. The potential also exists to incorporate new environmental DNA technologies into routine monitoring to deliver high-resolution species data and identify indicator species that are cursors of specific disturbances. Unless more targeted action is taken to safeguard biodiversity, we may fail to pass onto future generations many of the values that comprise what is universally regarded as the world’s most iconic coral reef ecosystem.
We describe Isorchis cannoni n. sp. from the rabbitfishes Siganus fuscescens (Houttuyn) and Siganus lineatus (Valenciennes) (Siganidae) collected off Heron Island, southern Great Barrier Reef, Australia and, using molecular data, demonstrate that ‘ Cercariae queenslandae II’ of Cannon (1978) from the gastropod Clypeomorus batillariaeformis Habe & Kosuge (Cerithiidae) is the larval form of this new species. The cercariae of I . cannoni n. sp. develop in rediae, encyst in the environment after emergence, and are inferred to then be consumed by grazing rabbitfish. Additionally, we provide a new report of Isorchis currani Andres, Pulis & Overstreet, 2016 from the type host, Selenotoca multifasciata (Richardson) (Scatophagidae) collected in Moreton Bay, south-east Queensland, Australia, greatly expanding the known geographical range of this species. Molecular sequence data (ITS1, ITS2 and 28S rDNA) generated for I . cannoni n. sp. and the new specimens of I . currani , confirm the identification of I . currani and demonstrate a distinct genotype for I . cannoni n. sp. relative to other species of Isorchis Durio & Manter, 1969, for which molecular data are available. Isorchis cannoni n. sp. is morphologically distinct from all other species in the genus, and is further distinguished by utilizing species of Siganidae as definitive hosts, rather than species of Chanidae or Scatophagidae. Because haploporid and atractotrematid cercariae have well-developed reproductive organs, we find cercariae of these closely related families morphologically distinguishable in the same way as adult trematodes: atractotrematids have two symmetrical testes and haploporids have a single testis or, rarely, two tandem or oblique testes.
A total of 1523 individuals of 34 species of chaetodontids from the Great Barrier Reef were examined for faustulid trematodes. Specimens resembling Paradiscogaster glebulae Bray, Cribb & Barker, 1994 were found in nine chaetodontid species at three localities. These specimens are shown, on the basis of combined morphological and molecular analysis, to comprise a complex of morphologically similar and partly cryptic species. The complex may comprise as many as six distinct species of which three are resolved here. The true P. glebulae is identified in Chaetodon ornatissimus Cuvier, 1831, C. aureofasciatus Macleay, 1878, C. plebeius Cuvier, 1831, C. rainfordi McCulloch, 1923 and C. speculum Cuvier, 1831. Two new species are described, Paradiscogaster munozae n. sp. from Heniochus varius (Cuvier, 1829), H. chrysostomus Cuvier, 1831 and Chaetodon citrinellus Cuvier, 1831 and P. melendezi n. sp. from Chaetodon kleinii Bloch, 1790. In terms of morphology the three species differ most clearly in the development of the appendages on the ventral sucker. The three species differ at 3-6 consistent bp of ITS2 rDNA. The host-specificity of the three species differs strikingly. Paradiscogaster melendezi n. sp. infects just one fish species, P. glebulae infects species of only one clade of Chaetodon, and P. munozae n. sp. infects quite unrelated species. The basis of this unusual pattern of host-specificity requires further exploration. Two of the species recognised here, P. glebulae and P. munozae n. sp., showed apparent intraindividual variation in the ITS2 rDNA sequences as demonstrated by clear, replicated double peaks in the electropherograms.
Copyright © 2015. Published by Elsevier Ireland Ltd.
The genus Aphalloides Dollfus, Chabaud & Golvan, 1957 consists of two species parasitic in the body cavity of sand gobies. Its systematic position in the superfamily Opisthorchioidea Looss, 1899 is unresolved and it has been placed by various authors in three families, i.e. Cryptogonimidae Ward, 1917, Heterophyidae Leiper, 1909 and Opisthorchiidae Looss, 1899. Its type-species, Aphalloides coelomicola Dollfus, Chabaud & Golvan, 1957, is here reported from the Caucasian dwarf goby Knipowitschia caucasica (Berg) in the lagoon Atanasovsko Lake, Black Sea coast of Bulgaria (new geographical record). The species is redescribed based on light and scanning electron microscopy demonstrating some characters typical for the Cryptogonimidae but also characters distinguishing it from the other genera of the family such as the lack of tegumental spines and the presence of a short excretory vesicle, which does not extend into the forebody. Phylogenetic analysis of the D2-D3 expansion segments of the 28S rRNA gene suggests phylogenetic relationships of Aphalloides coelomicola with the cryptogonimid Centrovarium lobotes (MacCallum, 1895). These data support the affiliation of the genus Aphalloides to the family Cryptogonimidae. The peculiar morphology of the species in the genus is explained by their unusual life-cycles characterised by progenetic development; sand gobies being simultaneously second intermediate and definitive hosts.
SUMMARY The effective use of biological tags in stock assessment relies on the reliable identification of the parasites concerned. This may be compromised if cryptic species are not recognized. Here we review what is known about cryptic species in aquatic hosts and its potential importance in this respect. Although strictly cryptic species may be considered as species which can be distinguished only by molecular data, we accept the far looser but more practical definition of species that cannot be readily distinguished morphologically. Cryptic species appear to have been identified most frequently as occurring in separate host species; this is heartening in that this has no significant impact on tagging studies. But cryptic species have occasionally been identified in single hosts sympatrically and are relatively common in geographically distinct populations of the same host species. Ignorance of both kinds of occurrences has the capacity to undermine the reliability of tagging analysis. We review in detail what is known of intra- and interspecific genetic variation over geographical ranges in the trematodes, based on recent molecular studies. Although the existence of cryptic species and evidence of intraspecific variability may appear daunting, we suspect that these complexities will add, and indeed have already added, to the sophistication of the information that can be derived from tagging studies.
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.
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) 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. novaecaledoniae 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. elongata (Gu & Shen, 1979) n. comb. based on morphological and ecological (host group) agreement with A. novaecaledoniae. Bayesian inference analysis of LSU rDNA revealed that A. novaecaledoniae 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.
Fishes representing 17 families, 27 genera and 40 species were examined. Five families of monogeneans representing six genera, 11 families of diagenetic trematodes representing 17 genera, four families of cestodes representing five genera, two families of nematodes representing three genera, and two families of acanthocephalans representing three genera were recorded. -from Authors
The following Digenea are described, recorded or figured from Heron Island and Fairfax Island in the southern Great Barrier Reef, off Queensland, northeastern Australia. Opegaster ditrematis from Apogon sp., Allopodocotyle epinepheli from Epinephelus quoyanus, Podocotyloides stenometra from Chaetodon rainfordi and C. plebius, Cainocreadium epinepheli from E. quoyanus and E. merra, Pacificreadium serrani (syn: Hamacreadium ghardagense) from Plectropomus leopardus, Hamacreadium mutabile (with 10 new synonyms) from Lutjanus amabilis, Helicometra fasciata from E. fasciata and E. merra, Macvicaria macassarensis n. comb. from Lethrinus chrysostomus, M. heronensis sp. nov. from L. chrysostomus and Gymnocranius bitorquatus, Pseudoplagioporus interruptus from L. chrysostomus, Orthodena tropica from L. chrysostomus, Propycnadenoides philippinensis (syn: Labrifer gymnocrani) from G. bitorquatus, Neochoanostoma avidabira gen, et sp. nov. from G. bitorquatus, N. bariadiva sp. nov. from G. bitorquatus. Plagioporus japonica is transferred to Macvicaria as a new combination. A key to the opecoelids from the southern Great Barrier Reef is given.
The effects of parasites on coral reef fishes are largely unexplored and unknown. In other fish-parasite systems, parasites may have far reaching effects upon their hosts, leaving few aspects of their host's biology unaffected. In French Polynesia, coral reef fishes are relatively well studied, but the effects of parasites upon the coral reef fish communities there are unevaluated. As a first step, we conducted a survey of the macroparasites of coral reef fishes in French Polynesia. We found a diverse array of parasites infecting fishes, including cestodes, copepods, digeneans, isopods, monogeneans, and nematodes. Diversity of digeneans, the most common parasite group, was lower in French Polynesia than on the Great Barrier Reef. The majority (69%) of fishes examined were infected with at least one species of parasite. Finally, we discuss the potential of parasites to influence coral reef fish communities by altering host life histories, interspecific interactions, community structure, and larval dynamics.
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.
MrBayes 3 performs Bayesian phylogenetic analysis combining information from different data partitions or subsets evolving under different stochastic evolutionary models. This allows the user to analyze heterogeneous data sets consisting of different data types—e.g. morphological, nucleotide, and protein—and to explore a wide variety of structured models mixing partition-unique and shared parameters. The program employs MPI to parallelize Metropolis coupling on Macintosh or UNIX clusters.
Availability: http://morphbank.ebc.uu.se/mrbayes
Contact: fredrik.ronquist@ebc.uu.se
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To whom correspondence should be addressed.
The sanguinicolids Paracardicoloides yamagutii Martin, 1974 and Plethorchis acanthus Martin, 1975 were obtained from their definitive hosts, Anguilla reinhardtii Steindachner and Mugil cephalus Linnaeus (respectively) in the tributaries of the Brisbane River, Queensland, Australia. Two putative sanguinicolid cercariae were collected from a hydrobiid gastropod, Posticobia brazieri Smith, in the same waters. The two cercariae differ markedly in size and the form of their sporocysts. Both putative cercariae develop in the digestive gland of Po. brazieri. The ITS2 rDNA region from these sanguinicolids and a Clinostomum species (utilised as an outgroup due to the close morphological similarities between the cercarial stages of the Clinostomidae and the Sanguinicolidae) were sequenced and aligned. Comparison of the ITS2 sequences showed one cercaria to be that of P. yamagutii. This is the first sanguinicolid life history determined by a molecular method. P. yamagutii is the fourth sanguinicolid known to utilise a freshwater hydrobiid gastropod as its intermediate host. ITS2 rDNA is effective in distinguishing sanguinicolids at the species level.
There is a push to fully document the biodiversity of the world within 25 years. However, the magnitude of this challenge, particularly in marine environments, is not well known. In this study, we apply DNA barcoding to explore the biodiversity of gonodactylid stomatopods (mantis shrimp) in both the Coral Triangle and the Red Sea. Comparison of sequences from 189 unknown stomatopod larvae to 327 known adults representing 67 taxa in the superfamily Gonodactyloidea revealed 22 distinct larval operational taxonomic units (OTUs). In the Western Pacific, 10 larval OTUs were members of the Gonodactylidae and Protosquillidae where success of positive identification was expected to be 96.5%. However, only five OTUs could be identified to species and at least three OTUs represent new species unknown in their adult form. In the Red Sea where the identification rate was expected to be 75% in the Gonodactylidae, none of four larval OTUs could be identified to species; at least two represent new species unknown in their adult forms. Results indicate that the biodiversity in this well-studied group in the Coral Triangle and Red Sea may be underestimated by a minimum of 50% to more than 150%, suggesting a much greater challenge in lesser-studied groups. Although the DNA barcoding methodology was effective, its overall success was limited due to the newly discovered taxonomic limitations of the reference sequence database, highlighting the importance of synergy between molecular geneticists and taxonomists in understanding and documenting our world's biodiversity, both in marine and terrestrial environments.
Lobosorchis tibaldiae n. gen. and n. sp. (Digenea: Cryptogonimidae) is described from the intestine, pyloric ceca, and rectum of 2 species of Lutjanus (Pisces: Lutjanidae), Lutjanus carponotatus and Lutjanus fulviflamma, from the Great Barrier Reef, Queensland, Australia, and New Caledonia. The genus is tentatively placed in the Neochasminae and is distinguished within the Cryptogonimidae by the combination of follicular testes, oral spines, and vitelline follicles restricted to the anterior region of the body not extending posteriorly to the ventral sucker.
Introduction to general state-space Markov chain theory. In W. R. Gilks, S. Richardson, and D. J. Spiegelhalter (Eds.), Markov Chain Monte Carlo in Practice, Chapter 4, pp. 59-74. London: Chapman and Hall. Yang, Z., R. Nielsen, N. Goldman, and A.-M. K. Pedersen (2000). Codon- substitution models for heterogeneous selection pressure at amino acid sites. Genetics 155, 431-449. Yang, Z. and B. Rannala (1997). Bayesian phylogenetic inference using DNA sequences: A Markov chain Monte Carlo method. Molecular Biology and Evolution 1, 717-724. Yang, Z. H. (1993). Maximum-likelihood-estimation of phylogeny from DNA- sequences when substitution rates differ over sites. Molecular Biology and Evolution I0(6), 1396-1401. Zuckerkandl, E. (1987). On the molecular evolutionary clock. Journal of Molec- ular Evolution 26, 34-46. Zuckerkandl, E. and L. Pauling (1962). Molecular disease, evolution, and genic heterogeneity. In M. Kasha and B. Pullman (Eds.), Horizons in Biochem- istry, pp. 189-225. Ne
A survey of the parasites of Indo-West Pacific Haemulidae revealed the presence of three new cryptogonimid (Digenea: Cryptogonimidae) species warranting two new genera, Beluesca littlewoodi n. gen., n. sp. and B. longicolla n. sp. from the intestine and pyloric caeca of Plectorhinchus gibbosus and Chelediadema marjoriae n. gen., n. sp. from the intestine and pyloric caeca of Diagramma labiosum, P. albovittatus and P. gibbosus from Heron and Lizard Islands off the Great Barrier Reef, Australia. Beluesca n. gen. is distinguished from all other cryptogonimid genera by the combination of an elongate body, funnel-shaped oral sucker, relatively small number of large oral spines, highly lobed ovary, opposite to slightly oblique testes, uterine loops that are restricted to the hindbody and extend well posterior to the testes and vitelline follicles that may extend from the ovary into the forebody, but do not extend anterior to the intestinal bifurcation. Pseudallacanthochasmus plectorhynchi Mamaev, 1970 is transferred to Beluesca as B. plectorhyncha (Mamaev, 1970) n. comb. based on morphological and ecological (host preference) characteristics. Chelediadema n. gen. is distinguished from all other cryptogonimid genera by the combination of a lanceolate body, relatively small number of large oral spines, prepharynx that is much longer than the oesophagus, tandem testes, uterine loops that are extensive in the hindbody and extend well posterior to the testes and vitelline follicles that extend from the ovary to the pharynx. Morphological analysis of the three species described here was augmented with DNA sequence analyses utilizing data from the large subunit (LSU) and the internal transcribed spacers (ITS) 1 and 2, and 5.8S nuclear ribosomal DNA. Sequence data from the LSU and ITS (encompassing the ITS1, 5.8S and ITS2) of the taxa examined here were aligned with those reported for other cryptogonimids, Caulanus thomasi, Latuterus tkachi, Neometadena ovata, four representative species of Retrovarium and an undescribed species of Siphoderina, for comparative purposes and to explore levels of interspecific and intergeneric variation among these taxa. Minimum evolution analysis was conducted on a combined (LSU and ITS) dataset to explore relationships among these genera. Despite their superficial morphological and host preference similarities, species of Beluesca and Chelediadema were genetically distant from each other. Interspecific and intergeneric variation among the species described here is similar to that reported for other cryptogonimids.
Six digeneans are reported from marine fishes of the Kuwaiti coast of the Arabian Gulf: Pleorchis sciaenae Yamaguti, 1938, from Otolithes argenteus; Tergestia pauca Freitas and Kohn, 1965, from Scomberoides commersonianus and Trachurus trachurus; Allobacciger macrorchis Hafeezullah and Siddiqi, 1970, from Scolopsis ruppelli (new host record); Paradiscogaster farooqii Hafeezullah and Siddiqi, 1970, from Scatophagus argus; Neoparacryptogonimus sphericus sp. n. from Lutjanus coccineus (type host) and Batrachus grunniens; and Paracryptogonimus ramadani sp. n. from Lutjanus fulviflamma. Pleorchis arabicus Al-Yamani and Nahhas, 1981, is a synonym of P. sciaenae. Tergestia pectinata of Nahhas and Cable (1964), Nahhas and Short (1965), is considered a synonym of Tergestia pauca. New locality records are established for Tergestia pauca, Allobacciger macrorchis, and Paradiscogaster farooqii. A key to species of Paracryptogonimus and Neoparacryptogonimus is given.
— We studied sequence variation in 16S rDNA in 204 individuals from 37 populations of the land snail Candidula unifasciata (Poiret 1801) across the core species range in France, Switzerland, and Germany. Phylogeographic, nested clade, and coalescence analyses were used to elucidate the species evolutionary history. The study revealed the presence of two major evolutionary lineages that evolved in separate refuges in southeast France as result of previous fragmentation during the Pleistocene. Applying a recent extension of the nested clade analysis (Templeton 2001), we inferred that range expansions along river valleys in independent corridors to the north led eventually to a secondary contact zone of the major clades around the Geneva Basin. There is evidence supporting the idea that the formation of the secondary contact zone and the colonization of Germany might be postglacial events. The phylogeographic history inferred for C. unifasciata differs from general biogeographic patterns of postglacial colonization previously identified for other taxa, and it might represent a common model for species with restricted dispersal.
DNA sequences of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) were determined for 11 species from four genera of Didymozoinae (Indodidymozoon, Helicodidymozoon, Rhopalotrema and Neometadidymozoon) and a species of the Lecithasteridae, Lecithaster stellatus. Sequences were used to test the validity of species recognised on morphological criteria and to infer phylogenetic relationships. Sequences of the 11 didymozoids differed by 0.5% to 19%. Our phylogenetic analyses: (i) indicate that species in the genera Helicodidymozoon and Rhopalotrema are a monophyletic group; (ii) support separation of the genus Helicodidymozoon from the genera Indodidymozoon and Neometadidymozoon; and (iii) support recognition of Rhopalotrema as a genus distinct from Neometadidymozoon. We found the gonochoristic species, I. pearsoni and I. suttiei, to be genetically similar to the hermaphroditic species in the genus Indodidymozoon and found no evidence to indicate that they belong in a separate genus.
During August and September 1909 I had an opportunity, thanks to the Government Grant Committee of the Royal Society, of making a fairly comprehensive examination of the parasites of fishes from the English Channel at the Marine Biological Laboratory, Plymouth. During that time nearly five hundred fishes, belonging to about 80 species, were dealt with and a very extensive collection of parasites made. A considerable number of species were obtained many of which are new to British waters but the number of absolutely new species amounted to very few. Of these I am describing here four of the most noteworthy, three of which appear to be of new generic type. A complete account of the investigations will be published later.
Twelve species of lepocreadiid trematodes are reported from marine fishes of Waltair Coast. These include 3 new genera: Lobalocreadium, Opisthogonoporoides, and Cotylocreadium, and 6 new species: Preptetos chaetodoni sp. n. from Chaetodon pictus; Opechona waltairensis sp. n. from Rastrelliger kanagurta; Lobatocreadium manteri gen. et sp. n. from Sufflamen capistratus and Hemibalistes chrysoptera; Multitestis bengalensis sp. n. from Platax teira; Opisthogonoporoides hanumanthai gen. et sp. n. from Siganus oramin, Acanthurus mata, and A. strigosus; and Pseudocreadium indicum sp. n. from Monacanthus choirocephalus. Other species reported are Opechona bacillaris (Molin, 1859), Lepocreadioides indicum Srivastava, 1941, Transversocreadium cablei Hafeezullah, 1970, Bianium plicitum (Linton, 1928), Cotylocreadium triacanthi (Hafeezullah, 1970) gen. et comb. n., and Aephnidiogenes senegalensis Dollfus and Capron, 1958. The new combinations suggested are: Lobatocreadium exiguum (Manter, 1963) for Lepocreadium exiguum Manter, 1963; and Cotylocreadium triacanthi (Hafeezullah, 1970) for Diplocreadium triacanthi Hafeezullah, 1970.
Members of the genus Schistosoma are generally grouped on the basis of egg morphology, intermediate host specificity, and geographic origin. We have tested hypotheses based on these groupings by phylogenetic analysis of nuclear ribosomal (ITS2) and mitochondrial (COI) nucleotide sequences. Both mitochondrial and nuclear DNA data strongly support "traditional" hypotheses that (a) members of the Schistosoma haematobium group form a monophyletic clade, (b) members of the S. mansoni group form a monophyletic clade, (c) S. japonicum and S. mekongi form a monophyletic group relative to other schistosomes, and (d) the African schistosomes form a clade to the exclusion of the two Asian species.
The taxonomic history of members of the 37-collar-spine group within the genus. Echinostoma has been very confused. We obtained DNA sequence data from the nuclear rDNA ITS1, 5.8S and ITS2 of 7 nominal species belonging to this group, Echinostoma trivolvis (Cort, 1914), E. revolutum (Frölich, 1802), E. caproni Richard, 1964, E. liei Jeyarasasingam et al. 1972, E. paransei Lie & Basch, 1967, two African isolates, E. sp.I and E. sp.II, and of one 28-collar-spined echinostome, E. hortense (Asada, 1926). Five of the eight species were clearly distinguishable using ITS data. Sequences from the remaining three taxa, E. caproni, E. sp.II and E. liei were identical to one another and the group containing these taxa was distant from other 37-collar-spine species on a phylogenetic tree. E. trivolvis and E. paraensei form a second, but less distinct group within the 37-collar-spine group. The resolution obtained using DNA sequencing will assist in the current reclassification of the group. It also provides a model for future work on sibling species.
The Digenea is one of five major helminth assemblages represented in Australian animals. History of the study of digeneans in Australia is reviewed briefly to show that it has never been subjected to the kind of sustained study needed to reach an understanding of it. The Australian vertebrate fauna comprises over 5500 species. These have so far been shown to harbour just over 70 families, about 306 genera and 566 species of digeneans. Digeneans occur in all classes of vertebrates in Australia but are distributed very unevenly; aquatic hosts are generally most heavily infected, but many terrestrial species are also infected. Particular weaknesses in knowledge of the fauna concern the bats, cetaceans and teleosts. Another weakness is in knowledge of life-cycles; representative life-cycles are known for only about 20 of the 70 families known in Australia. Estimates of the overall size of the fauna are dependent on an understanding of sampling strategies, the heterogeneity of distribution of the fauna, and the nature of host-specificity. These subjects are reviewed briefly and an estimate of the total fauna is made. There may be as many as 6000 species of digeneans in Australia.
Immature bivesiculid trematodes collected from the intestine of Thlalassoma lunare (Labridae) are shown to be morphologically consistent with adults of Bivesicula claviformis from Epinephelus fasciatus (Serranidae). In addition, the immature bivesiculids have the same sequence for the second internal transcribed spacer of the ribosomal DNA. Comparison with three other species of Bivesiculidae showed differences of between 23% and 30%. These results show that bivesiculids may have three-host life-cycles in addition to the two-host life-cycles that have been demonstrated previously. The three-host life-cycle enables bivesiculids to infect large carnivorous fishes.
Three nucleotide data sets, two nuclear (ribosomal internal transcribed spacer regions 1 and 2, ITS1 and ITS2) and one mitochondrial (cytochrome c oxidase subunit 1, CO1), were analysed using distance matrix and maximum likelihood methods to determine the inter-relationships amongst the four species attributed to the genus Ichthyocotylurus Odening, 1969. Sequence data obtained from all gene loci investigated supported the position of Ichthyocotylurus variegatus as a species discrete from Ichthyocotylurus platycephalus. Phylogenetic analyses yielded congruent trees, with I. variegatus isolates comprising a common clade to which I. platycephalus constitutes a sister taxon. Ichthyocotylurus erraticus and Ichthyocotylurus pileatus were found to demonstrate a similarly close inter-specific relationship. The greatest intra-generic divergence occurred in the CO1 region (16% variability), with resultant disparities in three to eight encoded amino acids. PCR amplification yielded multiple ITS1 products for all Ichthyocotylurus spp. Analyses of equivalent-sized amplicons showed 5.4% intra-generic variation and several point mutations between I. variegatus isolates from different geographical localities and from different piscine hosts. The ITS2 locus was extremely conserved, with less than 1% variation between species. No intra-specific variation was recorded for any CO1 or ITS2 sequences.
The status of Schistosoma sinensium (samples from Thailand and from Sichuan, China) relative to other species of the genus Schistosoma was investigated using DNA sequences from the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene (partial) and the nuclear ribosomal DNA second internal transcribed spacer 2 (ITS2). Trees inferred from these sequences place S. sinensium as sister to the S. japonicum group and suggest a basal position in the clade utilizing snails of the family Pomatiopsidae. The sequence differences between specimens of S. sinensium from China and Thailand are at least as great as between S. malayensis and S. mekongi. Schistosoma sinensium is probably best regarded as a species complex.
A phylogenetic study of 8 North American and European species of frog lung flukes belonging to Haematoloechus was conducted using approximately 850 to 1,000 bases of the intemal transcribed spacer region (ITS 1 + 5.8S + ITS 2) and 1,250 bases of the large subunit (LSU) of the nuclear ribosomal DNA. Adequate phylogenetic resolution could not be obtained from 5.8S or ITS 2 data. Analysis of ITS 1 data produced 2 equally parsimonious trees that differed only in the position of Haematoloechus breviplexus relative to H. medioplexus and H. varioplexus. Single, identical trees were produced by analysis of both LSU sequence data and a data set comprised of all ITS and LSU data. All trees demonstrated 3 distinct evolutionary lineages within the Holarctic Haematoloechus examined. The results confirmed the taxonomic validity of H. abbreviatus and demonstrated that the presence or absence of extracecal uterine loops is not a character meaningful to the recognition of evolutionary lineages or differentiation of genera. Examination of ITS sequence data revealed almost no intraspecific variation within 5 species of Haematoloechus and demonstrated an approximately 150-base indel common to the North American H. longiplexus and the European H. asper. Two of 3 clades revealed by the phylogenetic analyses are comprised of both European and North American species, indicating that lineages of Haematoloechus arose before the breakup of Laurasia and radiated after Eurasia and North America split. Within each of 3 evolutionary lineages, members share similar patterns of arthropod host specificity distinct from patterns found in the other lineages. This suggests that second intermediate host specificity may be a trait that has been conserved through evolutionary time.
In just over a decade, the use of molecular approaches for the recognition of parasites has become commonplace. For trematodes, the internal transcribed spacer region of ribosomal DNA (ITS rDNA) has become the default region of choice. Here, we review the findings of 63 studies that report ITS rDNA sequence data for about 155 digenean species from 19 families, and then review the levels of variation that have been reported and how the variation has been interpreted. Overall, complete ITS sequences (or ITS1 or ITS2 regions alone) usually distinguish trematode species clearly, including combinations for which morphology gives ambiguous results. Closely related species may have few base differences and in at least one convincing case the ITS2 sequences of two "good" species are identical. In some cases, the ITS1 region gives greater resolution than the ITS2 because of the presence of variable repeat units that are generally lacking in the ITS2. Intraspecific variation is usually low and frequently apparently absent. Information on geographical variation of digeneans is limited but at least some of the reported variation probably reflects the presence of multiple species. Despite the accepted dogma that concerted evolution makes the individual representative of the entire species, a significant number of studies have reported at least some intraspecific variation. The significance of such variation is difficult to assess a posteriori, but it seems likely that identification and sequencing errors account for some of it and failure to recognise separate species may also be significant. Some reported variation clearly requires further analysis. The use of a "yardstick" to determine when separate species should be recognised is flawed. Instead, we argue that consistent genetic differences that are associated with consistent morphological or biological traits should be considered the marker for separate species. We propose a generalised approach to the use of rDNA to distinguish trematode species.
The phylogenetic relationships of 27 species of common Indo-Pacific snappers (Lutjanidae) were explored using the 16S ribosomal RNA and cytochrome b mitochondrial genes with minimum evolution, maximum parsimony, maximum likelihood and Bayesian inference analyses. Included were species representing four subfamilies, the Caesioninae, Etelinae, Paradicichthyinae, and Lutjaninae. Members of the closely related families Haemulidae, Lethrinidae, Nemipteridae and Sparidae, were included for outgroup comparisons and to explore the relationships between the Haemuloidea, Lutjanoidea and Sparoidea. Monophyly of the Lutjanidae was resolved. The Caesioninae was nested within the Lutjaninae, supporting the recent view that the Caesionidae should be treated as a synonym of the Lutjanidae. The subfamilies Etelinae and Paradicichthyinae were resolved as sister taxa to the remainder of the Lutjanidae, which corroborates previous cladistic analyses conducted to determine relationships of lutjanid subfamilies. Bayesian inference and maximum likelihood analyses suggest that Macolor is the sister taxon to the Caesioninae and may represent a transitional form between the Lutjaninae and Caesioninae. Three species of Western Atlantic lutjanids, Lutjanus campechanus, L. synagris, and Rhomboplites aurorubens, were included in the analyses to examine their relationships to Indo-Pacific species; they formed a well-supported clade nested within Pacific lutjanines suggesting that Atlantic species of Lutjaninae are derived from an Indo-Pacific lineage. Results of our molecular phylogenetic analyses are congruent with the general morphology and external colouration of the resolved groups of species of Lutjanus. The "black spot" complex containing L. fulviflamma, L. monostigma, and L. russelli was resolved with strong support, and had L. carponotatus nested within. The morphology of L. carponotatus suggests a close relationship to this group, and the lack of the black spot near the lateral line below the soft dorsal fin is possibly a secondary loss. As expected, the "blue-lined" species, L. kasmira and L. quinquelineatus, formed a strongly supported clade. Lutjanus bohar and L. gibbus, both distinctly red, long-lived fish that often accumulate large quantities of ciguatera toxin in their tissues, were resolved as sister taxa.
We describe 11 new species of cryptogonimids belonging to Retrovarium n. gen., from eight species of Lutjanidae and one species of Haemulidae, from the Great Barrier Reef, French Polynesia and the Maldives. We also transfer Neoparacryptogonimus saccatus (Manter, 1963) and Neoparacryptogonimus sphericus Nahhas, Sey & Nishimoto, 1998 to Retrovarium. The morphologically based taxonomic approach was augmented with DNA sequence data from three nuclear ribosomal DNA regions (28S, ITS1 and ITS2) to explore the species integrity, biogeographic distribution and evolution of the species recognised here. Sequencing included multiple replicates and revealed 11 distinct genotypes which corroborated our morphologically based hypotheses of putative species present in the system. There was no intraspecific variation and all three rDNA regions differed between every combination of species. Two species exhibited wide geographic ranges, having identical rDNA sequences between the Great Barrier Reef and the Maldives, localities separated by over 9600 km. One host species, Symphorus nematophorus, proved to be exceptionally rich, harbouring six species. Minimum evolution analyses were conducted on each of the rDNA datasets independently; minimum evolution, maximum likelihood and Bayesian inference analyses were conducted on a combined (28S, ITS1 and ITS2) dataset for sequence comparison purposes and to explore the evolutionary history of these parasites. To examine the coevolutionary history of this complex, assessment of phylogenetic relationships between the 23 species of Lutjanidae and two species of Haemulidae collected during this survey was performed with data from 16S and cytochrome b mtDNA using Bayesian inference analysis. Despite the high host specificity observed in most of the species, mapping of the parasites on the host phylogeny revealed an absence of strict coevolution or co-descent within this complex. Overall, Retrovarium appears to have had an exceptionally patchy radiation, failing to infect many taxa, infecting species with no readily discernible pattern, and radiating dramatically within one species.
The Clustal W and Clustal X multiple sequence alignment programs have been completely rewritten in C++. This will facilitate
the further development of the alignment algorithms in the future and has allowed proper porting of the programs to the latest
versions of Linux, Macintosh and Windows operating systems.
Availability: The programs can be run on-line from the EBI web server: http://www.ebi.ac.uk/tools/clustalw2. The source code and executables for Windows, Linux and Macintosh computers are available from the EBI ftp site ftp://ftp.ebi.ac.uk/pub/software/clustalw2/
Contact: clustalw{at}ucd.ie
FishBase. World Wide Web electronic publication
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Einige Bermerkungen zur Nomenclatur der Trematoden
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Nouveaux trematodes du chien, par Hall et Wigdor. Recueil de Médecine Vétérinaire
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Entozoorum synopsis cui accedunt mantissa duplex et indices loupletissimi
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Rücker, Berlin, 811 pp.
Studies on the family Heterophyidae Odhner, 1914. Part III. Parasites belonging to a new subfamily Polyorchitreminae from an Indian fresh-water fish
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