Storm Martin

As part of a broad survey of the trematodes of damselfishes (Pomacentridae) in the tropical Indo-West Pacific, zoogonids were collected from multiple localities in Australia, New Caledonia, and French Polynesia. All zoogonid specimens collected were consistent with the subfamily Lecithostaphylinae, and morphological and molecular data (ITS2 and 28S rDNA, and cox1 mtDNA) were generated for most host-locality combinations to enable an integrative species delimitation. The collection comprised three species: Deretrema stratiotes n. sp. from four species of Abudefduf Forsskål from Ningaloo Reef in Western Australia, and two species consistent with the genus Lecithostaphylus Odhner, 1911 for which Innuptacola n. gen. is proposed based on phylogenetic and morphological distinction, the type-species I. gibsoni (Cribb, Bray & Barker, 1992) n. comb. (= L. gibsoni) from six species of Abudefduf in Ningaloo Reef, Queensland and New Caledonia, and I. torquata n. sp. from 12 pomacentrid species in Ningaloo Reef, the Great Barrier Reef in Queensland, and the Gambier Islands in French Polynesia. The new collection demonstrates that some zoogonid species are geographically widespread (from the Pacific Ocean to the Indian Ocean) and can infect a broad range of hosts (multiple genera within a family), whereas others are apparently geographically restricted and exhibit higher host-specificity (fishes within a single genus).

The description and delineation of trematode species is a major ongoing task. Across the field there has been, and currently still is, great variation in the standard of this work and in the sophistication of the proposal of taxonomic hypotheses. Although most species are relatively unambiguously distinct from their congeners, many are either morphologically very similar, including the major and rapidly growing component of cryptic species, or are highly variable morphologically despite little to no molecular variation for standard DNA markers. Here we review challenges in species delineation in the context provided to us by the historical literature, and the use of morphological, geographical, host, and molecular data. We observe that there are potential challenges associated with all these information sources. As a result, we encourage careful proposal of taxonomic hypotheses with consideration for underlying species concepts and frank acknowledgement of weaknesses or conflict in the data. It seems clear that there is no single source of data that provides a wholly reliable answer to our taxonomic challenges but that nuanced consideration of information from multiple sources (the ‘integrated approach’) provides the best possibility of developing hypotheses that will stand the test of time.

Examination of hundreds of individuals of 32 species of Acanthuridae from the Indo-West Pacific resulted in the collection of trematodes consistent with the genus Neohexangitrema Machida, 1984 from the northern and southern Great Barrier Reef (GBR, Queensland, Australia), Ningaloo Reef (Western Australia), Okinawa (Japan), New Caledonia, and Mo'orea and Rangiroa in French Polynesia. Specimens of Neohexangitrema spp. were primarily collected from two species of Zebrasoma, Z. scopas (Cuvier) and Z. velifer (Bloch), and less frequently from three species of Acanthurus. Specimens from Z. scopas and A. nigricans (Linnaeus) from French Polynesia are morphologically and genetically distinct and here described as N. blairi n. sp. This species appears to represent an unusual case of parasite endemism in French Polynesia. Two other morphotypes occurred, often together, in fishes from at least one of the other localities but not in French Polynesia. The first of these, from Ningaloo Reef, Okinawa, GBR and New Caledonia, is clearly morphologically and genetically distinct and is described as N. phytophaga n. sp. This species frequently has large amounts of undigested algae in the digestive tract and appears to be a herbivore in a herbivore. The second widespread morphotype comprised specimens from Z. scopas and Z. velifer consistent with N. zebrasomatis Machida, 1984 as originally described from Z. velifer from off southern Japan. Molecular analyses (cox1 mtDNA and ITS2 and 28S rDNA) consistently suggest that these new specimens represent two morphologically cryptic species, both infecting Z. scopas and Z. velifer, one only at Ningaloo Reef and the other from the GBR. Neither of these species can presently be positively identified as N. zebrasomatis given the lack of molecular data from the type-locality. We here propose new names for both taxa, N. obscura n. sp. for the species from the GBR and New Caledonia and N. cryptica n. sp. for the species from Ningaloo Reef. This proposal is made with the explicit understanding that one of the two may well (but will not necessarily) prove a synonym of N. zebrasomatis. This approach draws attention to the developing issue of the management of the names of combinations of cryptic trematode species.

The techniques employed to collect and store trematodes vary between research groups, and although these differences are sometimes necessitated by distinctions in the hosts examined, they are more commonly an artefact of instruction. As a general rule, we tend to follow what we were taught rather than explore new techniques. A major reason for this is that there are few technique papers in the published literature. Inspired by a collaborative workshop at the Trematodes 2024 symposium, we outline our techniques and processes for collecting adult trematodes from fishes and discuss the improvements we have made over 40 years of dissections of 20,000+ individual marine fishes. We present these techniques for two reasons: first, to encourage unified methods across the globe, with an aim to produce optimally comparable specimens across temporal periods, across geographic localities, and between research groups; and second, as a resource for inexperienced researchers. We stress the importance of understanding differences in host biology and the expected trematode fauna, which ultimately enables organised and productive dissections. We outline our dissection method for each key organ separately, discuss handling, fixation, and storage methods to generate the most uniform and comparable samples, and explore ethical considerations, issues of accurate host identification, and the importance and potential of clear record keeping.

Feeding habits of herbivorous fishes play an important role in shaping form and function of coastal marine ecosystems. Rabbitfishes (Siganidae) are important consumers of macroalgae on Indo-West Pacific coral reefs. However, it is unclear how their diet varies among and within species at biogeographical scales, casting doubt on their precise functional roles across different regions. The present study assessed the inter- and intraspecific diet variation of four rabbitfishes (Siganus trispilos, Siganus coralinus, Siganus virgatus, and Siganus doliatus) factored by morphological relatedness among populations from Ningaloo Reef (western Australia), the Great Barrier Reef (GBR, eastern Australia) and the Yaeyama Islands (Okinawa Prefecture, Japan). Results showed that region had a strong effect on diet, effectively reducing the expected effect of morphologic similitude. While intraspecific differences were only significant when populations inhabited different regions; interspecific differences were not as predicted, with different morphotypes having similar diets when populations inhabited the same regions. Rabbitfishes consumed more corticated and filamentous macroalgae on the GBR, more foliose and membranous macroalgae at the Yaeyama Islands, and more leathery macroalgae at Ningaloo Reef. The findings indicate that rabbitfishes have high diet plasticity, and hence their functional role as mediators of competition between macroalgae and corals can change across biogeographic regions. Local context is therefore important when assessing the diet and functional role of herbivorous fishes. As climate change unfolds, shifts in the distribution, trophic behaviour and function of species are expected, making the study of trophic plasticity more important.

Purpose
This study examined the metazoan ectoparasites of the Critically Endangered giant shovelnose ray, Glaucostegus typus, in the eastern Indian Ocean.

Methods
We screened 186 G. typus for ectoparasites in four coastal regions of Western Australia between 2020 and 2022: the Pilbara Region, Exmouth Gulf, Ningaloo Coast and Shark Bay.

Results
Five parasite taxa were encountered on 186 G. typus: Caligus furcisetifer (Copepoda: Caligidae), Dermopristis cairae (Monopisthocotyla: Microbothriidae), Branchellion plicobranchus and Stibarobdella macrothela (Hirudinida: Piscicolidae), and praniza larvae of unidentified gnathiid isopod/s (Isopoda: Gnathiidae). Two of these species, B. plicobranchus and S. macrothela, are reported for the first time on G. typus. Only C. furcisetifer and S. macrothela were relatively common, encountered on 31% and 40% of G. typus, respectively. Gnathiids were observed infrequently, encountered on 13% of G. typus, and D. cairae and B. plicobranchus were scarce, encountered on 1% and 2% of G. typus, respectively. Intensity of infection for C. furcisetifer and gnathiids increased with host length. Likelihood of infection varied seasonally for C. furcisetifer, being considerably lower in summer, and regionally for gnathiids, being greatest at Shark Bay. Intensity and likelihood of infection for S. macrothela increased with host length and varied regionally, being greatest at Shark Bay.

Conclusion
These findings improve our understanding of the downstream impacts for dependent parasites that might arise should populations of G. typus continue to decline.

Feeding habits of herbivorous fishes play an important role in shaping the form and function of coastal marine ecosystems. Rabbitfishes (Siganidae) are important consumers of macroalgae on Indo-West Pacific coral reefs. However, it is unclear how their diet varies among and within species at biogeographical scales, casting doubt on their precise functional roles across different regions. The present study assessed the inter- and intra-specific diet variation of four rabbitfishes (Siganus trispilos, Siganus corallinus, Siganus virgatus and Siganus doliatus) factored by morphological relatedness among populations from Ningaloo Reef (western Australia), the Great Barrier Reef (GBR, eastern Australia) and the Yaeyama Islands (Okinawa Prefecture, Japan). Results showed that the region had a strong effect on diet, effectively reducing the expected effect of morphologic similitude. While intra-specific differences were only significant when populations inhabited different regions; interspecific differences were not as predicted, with different morphotypes having similar diets when populations inhabited the same regions. Rabbitfishes consumed more corticated and filamentous macroalgae on the GBR, more foliose and membranous macroalgae at the Yaeyama Islands, and more leathery macroalgae at Ningaloo Reef. The findings indicate that rabbitfishes have high diet plasticity, and hence their functional role as mediators of competition between macroalgae and corals can change across biogeographic regions. Local context is therefore important when assessing the diet and functional role of herbivorous fishes. As climate change unfolds, shifts in the distribution, trophic behaviour and function of species are expected, making the study of trophic plasticity more important.Feeding habits of herbivorous fishes play an important role in shaping the form and function of coastal marine ecosystems. Rabbitfishes (Siganidae) are important consumers of macroalgae on Indo-West Pacific coral reefs. However, it is unclear how their diet varies among and within species at biogeographical scales, casting doubt on their precise functional roles across different regions. The present study assessed the inter- and intra-specific diet variation of four rabbitfishes (Siganus trispilos, Siganus corallinus, Siganus virgatus and Siganus doliatus) factored by morphological relatedness among populations from Ningaloo Reef (western Australia), the Great Barrier Reef (GBR, eastern Australia) and the Yaeyama Islands (Okinawa Prefecture, Japan). Results showed that the region had a strong effect on diet, effectively reducing the expected effect of morphologic similitude. While intra-specific differences were only significant when populations inhabited different regions; interspecific differences were not as predicted, with different morphotypes having similar diets when populations inhabited the same regions. Rabbitfishes consumed more corticated and filamentous macroalgae on the GBR, more foliose and membranous macroalgae at the Yaeyama Islands, and more leathery macroalgae at Ningaloo Reef. The findings indicate that rabbitfishes have high diet plasticity, and hence their functional role as mediators of competition between macroalgae and corals can change across biogeographic regions. Local context is therefore important when assessing the diet and functional role of herbivorous fishes. As climate change unfolds, shifts in the distribution, trophic behaviour and function of species are expected, making the study of trophic plasticity more important.

Forficuloecus pezopori Martin, Keatley & Ash n. sp. from the western ground parrot Pezoporus flaviventris North, 1911 (Psittaculidae) is proposed based on combined evidence from morphology and COI mitochondrial DNA. Phylogenetically, the new species is closest to its two known congeners from Western Australia: F. josephi Price, Johnson & Palma, 2008 from Bourke's parrot Neopsephotus bourkii (Gould, 1841) and the scarlet-chested parrot Neophema splendida (Gould, 1841), and F. palmai Guimarães, 1985 from the Australian ringneck parrot Barnardius zonarius (Shaw, 1805). Morphologically it is distinguishable by abdominal chaetotaxy and characters of the male genitalia, and is most similar to F. josephi and F. greeni Guimarães, 1985; the latter has no representative sequence data. Forficuloecus pezopori is the eleventh species of its genus and the only metazoan parasite known from P. flaviventris, which is among Australia's most endangered vertebrates. The new louse is apparently restricted to P. flaviventris and is therefore co-endangered, facing at least the same likelihood of extinction as its host. We recommend ongoing translocation and field monitoring efforts for P. flaviventris include monitoring but not treatment for lice infestations in otherwise healthy individuals, and that the care management plan for captive P. flaviventris considers that F. pezopori is similarly imperilled.
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•The first metazoan parasite known from the western ground parrot.•The new louse is likely restricted to its host and thus also critically endangered.•Conservation interventions for the parrot ought to consider the louse.•Host interventions are opportunities to discover and conserve parasites.

This study reports the metazoan ectoparasite fauna of juvenile Critically Endangered green sawfish, Pristis zijsron, and sympatric elasmobranchs in Western Australia. Five parasite taxa were found on 76 screened P. zijsron: Caligus furcisetifer (Copepoda: Caligidae), Dermopristis pterophila (Monogenea: Microbothriidae), Branchellion plicobranchus and Stibarobdella macrothela (Hirudinea: Piscicolidae), and praniza larvae of an unidentified gnathiid isopod. Only C. furcisetifer and D. pterophila were common, exhibiting discrepant site-specificity, with C. furcisetifer occurring mostly on the head and rostrum, and D. pterophila around the pectoral and pelvic fins. Intensity of infection for C. furcisetifer and D. pterophila increased with host total length and was influenced by host sex, but in opposite directions; intensity of C. furcisetifer was greater on female P. zijsron, whereas intensity of D. pterophila was greater on males. In the Ashburton River, likelihood of infection for C. furcisetifer and D. pterophila on P. zijsron increased with time since substantial freshwater discharge events, suggesting decreased salinity impacts both taxa. In addition to P. zijsron, five other sympatric elasmobranch species were opportunistically screened for ectoparasites in the study area: the giant shovelnose ray, Glaucostegus typus, the eyebrow wedgefish, Rhynchobatus palpebratus, the nervous shark, Carcharhinus cautus, the lemon shark, Negaprion acutidens, and the graceful shark, Carcharhinus amblyrhynchoides. Caligus furcisetifer was found on R. palpebratus; no other parasites of P. zijsron were found on other sympatric elasmobranch species. Conversely, Perissopus dentatus (Copepoda: Pandaridae) was found on all three carcharhinids but not on batoid rays (P. zijsron, G. typus or R. palpebratus).
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•The ectoparasite fauna of green sawfish, Pristis zijsron, is reported.•Caligus furcisetifer and Dermopristis pterophila were common on P. zijsron.•Stibarobdella macrothela, Branchellion plicobranchus and gnathiids were scarce.•Host size and sex affects infection intensity of C. furcisetifer and D. pterophila.•Eyebrow wedgefish, Rhynchobatus palpebratus, were also infected by C. furcisetifer.