Proposal of a new genus, Doorochen (Digenea: Lepocreadioidea), for reef-inhabiting members of the genus Postlepidapedon Zdzitowiecki, 1993.

A new genus, Doorochen n. gen., is erected for four species of Postlepidapedon Zdzitowiecki, 1993, all of which inhabit members of the labroid genus Choerodon Bleeker, the tuskfishes, and which molecular phylogenies have indicated are not congeneric with the type-species, P. opisthobifurcatum (Zdzitowiecki, 1990) Zdzitowiecki, 1993. Doorochen secundum (Durio & Manter, 1968) n. comb. from Choerodon graphicus (De Vis), the Graphic tuskfish, from the Great Barrier Reef (GBR) and New Caledonia is designated the type-species of the new genus. Other species recognised are Doorochen spissum (Bray, Cribb & Barker, 1997) n. comb. from C. venustus (De Vis), the Venus tuskfish, C. cyanodus (Richardson), the Blue tuskfish, and C. graphicus from the GBR; D. uberis (Bray, Cribb & Barker, 1997) n. comb. from C. schoenleinii (Valenciennes), the Blackspot tuskfish, and C. venustus from the GBR and Moreton Bay; and D. philippinense (Machida, 2004) n. comb. from C. anchorago (Bloch), the Orange-dotted tuskfish, from Philippine waters. In addition to these four species, two new species are described: D. zdzitowieckii n. sp. from C. fasciatus (Günther), the Harlequin tuskfish, and C. graphicus from the GBR; and D. goorchana n. sp. from C. anchorago from the GBR and Palau. The genus Postlepidapedon is now considered to comprise just two species, P. opisthobifurcatum and P. quintum Bray & Cribb, 2001. The relationships of Doorochen, Postlepidapedon, Myzoxenus Manter, 1934 and Intusatrium Durio & Manter, 1968 in the family Lepidapedidae Yamaguti, 1958 are discussed.

Allopodocotyle palmi sp. nov. and Prosorhynchus maternus Bray & Justine, 2006 (Digenea: Opecoelidae & Bucephalidae) from the Orange-Spotted Grouper Epinephelus coioides (Hamilton, 1822) off Bali, Indonesia, Described Using Modern Techniques.

BACKGROUND: The most convincing species of Allopodocotyle Pritchard, 1966 (Digenea: Opecoelidae) are known overwhelmingly from groupers (Serranidae: Epinephelinae). Six species of Allopodocotyle have been reported, collectively, from species of Cromileptes Swainson, 1839, Epinephelus Bloch, 1793 and Plectropomus Oken, 1817. These are A. epinepheli (Yamaguti, 1942), A. heronensis Downie & Cribb, 2011, A. manteri (Saoud & Ramadan, 1984), A. mecopera (Manter, 1940), A. plectropomi (Manter, 1963) and A. serrani (Yamaguti, 1952). In addition, a not yet fully described and unnamed seventh species, morphologically and phylogenetically close to A. epinepheli, was isolated from the orange-spotted grouper Epinephelus coioides (Hamilton, 1822) off Bali, Indonesia in 2016. An eighth species, again from E. coioides off Bali is described herein. METHODS: Morphological and phylogenetic analyses justify the recognition of A. palmi sp. nov., which is also genetically different from the as yet unnamed congener from the same host and locality. For the first time, 3D confocal laser scanning microscopy was applied to study and distinguish Digenea taxonomically. We introduce the 'Palm pattern', a new simplified way to visualise morphometric differences of related digenean taxa. RESULTS: Allopodocotyle palmi sp. nov. is distinguished from its congeners that infect groupers by its elongate body with a size > 2.7 mm and diagonal testes. The ovary is located mainly, and the anterior testis completely, in the posterior half of the body; the uterine coils are in the fourth eighth of the body. The cirrus-sac is 0.75-1.4 (1.1) mm long, its posterior extremity is well separated from the anterior extent of the vitelline fields, just reaching the anterior border of uterine coils. In addition, Prosorhynchus maternus Bray & Justine, 2006 (Bucephalidae) was isolated from E. coioides, representing the first record in Indonesia and the third record for this fish species. CONCLUSION: The biodiversity research in Indonesia is enhanced with a new species description based on modern and newly applied techniques.

Marine fish parasites of Vietnam: a comprehensive review and updated list of species, hosts, and zoogeographical distribution.

With a long coastline stretching from tropical to subtropical climate zones, and an immense exclusive economic zone with over 4000 islands, the Vietnamese marine waters support a rich and biodiverse parasite fauna. Although the first parasitological record was in 1898, systematic studies of the parasite fauna have increased during the last 50 years. This comprehensive review covers the current state of knowledge of marine fish parasites in Vietnam and lists 498 species found in 225 fish species, and their geographical distribution. In addition, 251 marine parasite species have newly been added to the already known fauna of 247 species since 2006 (more than two-fold increase). The most speciose group was the Digenea, which accounted for 43% of the total parasite species biodiversity, followed by Monogenea (23.5%), Crustacea (11.6%), Nematoda, and Acanthocephala (8.0% each). The shallow and muddy Gulf of Tonkin showed a rich parasite fauna, accounting for 66.3% of the whole marine parasite fauna of Vietnam, with Digenea accounting for 51% of the regional total parasite richness, followed by Monogenea (27%), Acanthocephala (8.8%), and Nematoda (5.8%). Only a few species belonged to Hirudinea, Myxozoa, and Cestoda, suggesting that these taxa may be understudied. Despite significant progress in studies of marine fish parasites in Vietnam since 2006, only about 12% and 13% of the total fish species have been examined for parasites in the whole country and the Gulf of Tonkin, respectively.

Title: Parasites des poissons marins du Vietnam : synthèse complète et mise à jour des listes d'espèces, des hôtes et de la distribution zoogéographique. Abstract: Avec un long littoral s'étendant des zones climatiques tropicales à subtropicales et une immense zone économique exclusive incluant plus de 4 000 îles, les eaux marines vietnamiennes abritent une faune parasitaire abondante et riche en biodiversité. Le premier signalement parasitologique remonte à 1898 et les études systématiques de la faune parasitaire se sont multipliées au cours des 50 dernières années. Cette synthèse complète couvre l'état actuel des connaissances sur les parasites des poissons marins au Vietnam et répertorie 498 espèces trouvées dans 225 espèces de poissons et leur répartition géographique. De plus, 251 espèces de parasites marins ont été nouvellement ajoutées à la faune déjà connue de 247 espèces depuis 2006 (soit une augmentation de plus du double). Le groupe le plus riche en espèces était les Digenea, qui représentaient 43% de la biodiversité totale des espèces de parasites, suivis des Monogenea (23,5 %), des Crustacea (11,6 %), des Nematoda et des Acanthocephala (8,0 % chacun). Le golfe peu profond et boueux du Tonkin a montré une riche faune parasitaire, représentant 66,3 % de l'ensemble de la faune parasitaire marine du Vietnam, avec les Digenea représentant 51 % de la richesse parasitaire totale régionale, suivi des Monogenea (27 %), Acanthocephala (8,8 %) et Nematoda (5,8 %). Seules quelques espèces appartenaient aux Hirudinea, Myxozoa et Cestoda, ce qui suggère que ces taxons pourraient être sous-étudiés. Malgré des progrès significatifs dans les études sur les parasites des poissons marins au Vietnam depuis 2006, seulement 12 % et 13 % des espèces de poissons ont été examinées, respectivement pour les parasites de l'ensemble du pays et du golfe du Tonkin.

A new species, new host records and life cycle data for lepocreadiids (Digenea) of pomacentrid fishes from the Great Barrier Reef, Australia.

A new species of lepocreadiid, Opechonoides opisthoporus n. sp., is described infecting 12 pomacentrid fish species from the Great Barrier Reef, Australia, with Abudefduf whitleyi Allen & Robertson as the type-host. This taxon differs from the only other known member of the genus, Opechonoides gure Yamaguti, 1940, in the sucker width ratio, cirrus-sac length, position of the testes, position of the pore of Laurer's canal, and relative post-testicular distance. The new species exhibits stenoxenic host-specificity, infecting pomacentrids from seven genera: Abudefduf Forsskål, Amphiprion Bloch & Schneider, Neoglyphidodon Allen, Neopomacentrus Allen, Plectroglyphidodon Fowler & Ball, Pomacentrus Lacépède and Stegastes Jenyns. Phylogenetic analyses of 28S rDNA sequence data demonstrate that O. opisthoporus n. sp. forms a strongly supported clade with Prodistomum orientale (Layman, 1930) Bray & Gibson, 1990. The life cycle of this new species is partly elucidated on the basis of ITS2 rDNA sequence data; intermediate hosts are shown to be three species of Ctenophora. New host records and molecular data are reported for Lepocreadium oyabitcha Machida, 1984 and Lepotrema amblyglyphidodonis Bray, Cutmore & Cribb, 2018, and new molecular data are provided for Lepotrema acanthochromidis Bray, Cutmore & Cribb, 2018 and Lepotrema adlardi (Bray, Cribb & Barker, 1993) Bray & Cribb, 1996. Novel cox1 mtDNA sequence data showed intraspecific geographical structuring between Heron Island and Lizard Island for L. acanthochromidis but not for L. adlardi or O. opisthoporus n. sp.

A world of taxonomic pain: cryptic species, inexplicable host-specificity, and host-induced morphological variation among species of Bivesicula Yamaguti, 1934 (Trematoda: Bivesiculidae) from Indo-Pacific Holocentridae, Muraenidae and Serranidae.

The taxonomy of species of Bivesicula Yamaguti, 1934 is analysed for samples from holocentrid, muraenid and serranid fishes from Japan, Ningaloo Reef (Western Australia), the Great Barrier Reef (Queensland), New Caledonia and French Polynesia. Analysis of three genetic markers (cox1 mtDNA, ITS2 and 28S rDNA) identifies three strongly supported clades of species and suggests that Bivesicula as presently recognized is not monophyletic. On the basis of combined morphological, molecular and biological data, 10 species are distinguished of which five are proposed as new. Bivesicula Clade 1 comprises seven species of which three are effectively morphologically cryptic relative to each other; all seven infect serranids and four also infect holocentrids. Bivesicula Clade 2 comprises three species of which two are effectively morphologically cryptic relative to each other; all three infect serranids and one also infects a muraenid. Bivesicula Clade 3 comprises two known species from apogonids and a pomacentrid, and forms a clade with species of Paucivitellosus Coil, Reid & Kuntz, 1965 to the exclusion of other Bivesicula species. Taxonomy in this genus is made challenging by the combination of low resolving power of ribosomal markers, the existence of regional cox1 mtDNA populations, exceptional and unpredictable host-specificity and geographical distribution, and significant host-induced morphological variation.

A paradigm for the recognition of cryptic trematode species in tropical Indo-west Pacific fishes: the problematic genus Preptetos (Trematoda: Lepocreadiidae).

Molecular data have transformed approaches to trematode taxonomy by providing objective evidence for the delineation of species. However, although the data are objective, the interpretation of these data regarding species boundaries is subjective, especially when different markers conflict. Conserved markers can lead to an underestimation of richness and those used for finer species delineation have the capacity to inflate species recognition, perhaps unrealistically. Here we examine molecular and morphological evidence for species recognition in an especially confusing system, the lepocreadiid genus Preptetos Pritchard, 1960 in acanthuriform fishes of the tropical Indo-west Pacific. We consider species boundaries within this genus based on combined data (ITS2 and 28S rDNA; cox1 mtDNA and morphometrics) for substantial new collections. Delineation of species using only morphological data suggest fewer species than analysis of the sequence data; the latter suggests the presence of potential cryptic species and analysis of different markers suggests the presence of differing numbers of species. We conclude that an integrative interpretation creates the most satisfying taxonomic hypothesis. In the light of the new data, we have chosen and propose a model of trematode species recognition that demands reciprocal monophyly in the most discriminating available molecular marker plus distinction in morphology or host distribution. By invoking these criteria, we distinguish eight species in our new tropical Indo-west Pacific collections. Six of these are new (Preptetos allocaballeroi n. sp., Preptetos paracaballeroi n. sp., Preptetos pearsoni n. sp., Preptetos prudhoei n. sp., Preptetos quandamooka n. sp. and Preptetos zebravaranus n. sp.) and we continue to recognise Preptetos cannoni Barker, Bray & Cribb, 1993 and Preptetos laguncula Bray & Cribb, 1996. Notably; two of the new species, P. allocaballeroi n. sp. and P. paracaballeroi n. sp., are morphologically cryptic relative to each other. Our criteria lead us to recognise, as species, populations with unvarying morphology and similar host relationships but which may have a complex population structure over their range. In our view, this paradigm has the capacity to render tractable the interpretation of the species status of the huge trematode fauna of the tropical Indo-west Pacific.

The biodiversity of marine trematodes: then, now and in the future.

Trematodes are the richest class of platyhelminths in the marine environment, infecting all classes of marine vertebrates as sexual adults and many phyla of marine invertebrates as part of their life cycles. Despite the cryptic nature of their existence (almost all marine trematodes are internal parasites), they have been the focus of study for almost 250 years, with the first species described in 1774. Here we review progress in the study of the "biodiversity" of these parasites, contrasting the progress made in the last 50 years (post-1971) to that in the almost 200 years before it (pre-1972). We consider an understanding of biodiversity to require knowledge of the species present in the system, an understanding of their evolutionary relationships (which informs higher classification), and, specifically for trematodes, an understanding of their complex life cycles. The fauna is now large, comprising well over 5,000 species. Although species description continues, we see evidence of a slow-down in all aspects of discovery. There has been only one completely new family identified since 1984 and the proposal of new genera is in decline as is the description of new species, especially for those of tetrapods. However, the extent to which this slow-down reflects an approach to the richness asymptote is made uncertain by changes in the field; reduced effort and difficulty of study may be important components of the effect. Regardless of how close we are to a complete description of the fauna, we infer that the outline is well-understood although the details are not. Adoption of molecular methodologies over the last 40 years have complemented morphometric analyses to facilitate objective recognition of species; however, despite these objective data, there is still inconsistency between authors on species delimitation. Molecular methodologies have also completely revolutionised inference of relationships at all levels, from within genera to between orders, and underpinned elucidation of novel life cycles. We expect the next 50 years to produce further dividends from technological innovations. The backdrop to the field will be global environmental concerns and the growing problem of funding for basic biodiversity studies.

Eight species of Lintonium Stunkard & Nigrelli, 1930 (Digenea: Fellodistomidae) in Australian tetraodontiform fishes.

We report eight species of Lintonium from tetraodontiform fishes from Australian waters and describe six of them as new. Two species are described from tetraodontids from the Great Barrier Reef (GBR): Lintonium kostadinovae n. sp. from Arothron nigropunctatus (Bloch & Schneider) and Arothron hispidus (Linnaeus); and Lintonium droneni n. sp. from A. nigropunctatus. Two species are described from temperate monacanthids: Lintonium crowcrofti n. sp. from Meuschenia hippocrepis (Quoy & Gaimard) and Meuschenia freycineti (Quoy & Gaimard) off Tasmania and from M. hippocrepis off Glenelg, South Australia and off Fremantle, Western Australia; and Lintonium blendi n. sp. from M. hippocrepis off Stanley, Tasmania. The final two new species are described from tropical monacanthids: Lintonium currani n. sp. from Cantherhines pardalis (Rüppell) from Ningaloo Reef, Western Australia; and Lintonium madhaviae n. sp. from Amanses scopas (Cuvier) from the southern GBR. Two previously described species are reported from tetraodontids: Lintonium pulchrum (Johnston, 1913) Yamaguti, 1954 from Arothron stellatus (Anonymous), A. hispidus, A. manilensis (Marion de Procé) and Lagocephalus lunaris (Bloch & Schneider) from the GBR and southern Queensland; and Lintonium consors (Lühe, 1906) Crowcroft, 1950 from A. nigropunctatus from the southern GBR. Sequence data for three markers (ITS2 and 28S rDNA and cox1 mtDNA) for six of the eight species (L. crowcrofti n. sp., L. currani n. sp., L. droneni n. sp., L. kostadinovae n. sp., L. madhaviae n. sp. and L. pulchrum) are the first for the genus and distinguish each species unambiguously. Many records of species of Lintonium, especially widespread records of the type species, L. vibex (Linton, 1900) Stunkard & Nigrelli, 1930, remain to be clarified. A key finding of the present study is that three fish species (A. hispidus, A. nigropunctatus and M. hippocrepis) are identified as harbouring either two or three species of Lintonium at individual localities.

Redescription of Aspidogaster limacoides Diesing, 1834 (Aspidogastrea: Aspidogastridae) from freshwater fishes of northern Germany.

Aspidogaster limacoides Diesing, 1834 (Aspidogastridae) is redescribed based on light and scanning electron microscopy of specimens from the stomach and intestine of Abramis brama, Rutilus rutilus and Scardinius erythrophthalmus (Actinopterygii: Cyprinidae). The fishes were sampled during 2018 and 2019 at Lake Tollense in Mecklenburg-Western Pomerania, Germany. The prevalence of A. limacoides was highest in R. rutilus (61.7%) followed by Scardinius erythrophthalmus (7.7%) and A. brama (2.9%), while it was absent in Perca fluviatilis from the same lake. The following structures of A. limacoides are described for the first time: a depression on the ventral side of the neck, variations in the number and the arrangement of alveoli, numerous pits scattered all over the body surface, the presence of a few papillae-like structures posterior lateral to the mouth, the number of marginal organs represented by openings of exocrine multicellular glands as shown in histology and the subterminal position of the excretory pore. These characters can be used to distinguish three species of Aspidogaster, namely, A. ijimai, A. conchicola and A. limacoides, suggesting that SEM is a useful and promising tool in differentiating Aspidogaster species. Comparison of molecular data of the ITS1-5.8S-ITS2 regions showed a 94% similarity to A. limacoides from the European part of Russia. Phylogenetic analysis showed that the present specimens clustered in the same clade with A. limacoides sensu stricto, forming a distinct group to the exclusion of congeners.

Digenean parasites of deep-sea teleosts: A progress report.

The developments in the study of digeneans of deep-sea fish in the 21st Century are documented and discussed. Most recent work has been on the bathyal fauna (i.e. 1,000m-2,999 m depth), with virtually nothing on the abyssal fauna (i.e. deeper than 3,000 m). The one study on hydrothermal vent digeneans has indicated that these regions probably harbour a distinctive fauna. The demarcation of the deep-sea fauna is blurred at the poles, where the cold-adapted fauna appears similar to the shallower bathyal fauna. The abyssal fauna, however, appears distinct, possibly due to adaptations to variable or ultra-high pressures. The digenean fauna of bathypelagic fishes is depauperate. Recent phylogenetic studies reinforce the view that the typical deep-sea fauna has radiated in the deep-sea. Encroachment into the deep from shallow water is relatively rare. Overall, the digenean fauna in the deep-sea is distinctly less diverse that the equivalent fauna in shallow waters. A major conclusion is that our understanding of the deep-sea digenean fauna is poor, and that much further work over a much wider area is needed.

Steringophorus merretti n. sp. (Digenea: Fellodistomidae) from the deep-sea fish Cataetyx laticeps Koefoed (Ophidiiformes: Bythitidae) from the Goban Spur, Northeastern Atlantic Ocean.

A new species of deep-sea digenean, Steringophorus merretti n. sp., is described from the bythitid fish Cataetyx laticeps in deep waters of the Goban Spur, Northeastern Atlantic. It is distinguishable from other described members of the genus by its tiny eggs and large cirrus-sac. A phylogenetic tree, based on 28S rDNA sequences, indicates that this species is embedded within a clade of deep-sea species and is sister to the eurybathic species S. thulini Bray & Gibson, 1980. Steringotrema robertpoulini Pérez-Ponce de León, Anglade & Randhawa, 2018 falls within the Steringophorus Odhner, 1905 clade. In view of this the morphological and biological characteristics of species of Steringophorus and Steringotrema are discussed.

Uncharted digenean diversity in Lake Tanganyika: cryptogonimids (Digenea: Cryptogonimidae) infecting endemic lates perches (Actinopterygii: Latidae).

BACKGROUND: Lake Tanganyika is considered a biodiversity hotspot with exceptional species richness and level of endemism. Given the global importance of the lake in the field of evolutionary biology, the understudied status of its parasite fauna is surprising with a single digenean species reported to date. Although the most famous group within the lake's fish fauna are cichlids, the pelagic zone is occupied mainly by endemic species of clupeids (Actinopterygii: Clupeidae) and lates perches (Actinopterygii: Latidae, Lates Cuvier), which are an important commercial source for local fisheries. In this study, we focused on the lake's four lates perches and targeted their thus far unexplored endoparasitic digenean fauna. METHODS: A total of 85 lates perches from four localities in Lake Tanganyika were examined. Cryptogonimid digeneans were studied by means of morphological and molecular characterisation. Partial sequences of the nuclear 28S rRNA gene and the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were sequenced for a representative subset of the specimens recovered. Phylogenetic analyses were conducted at the family level under Bayesian inference. RESULTS: Our integrative approach revealed the presence of six species within the family Cryptogonimidae Ward, 1917. Three out of the four species of Lates were found to be infected with at least one cryptogonimid species. Two out of the three reported genera are new to science. Low interspecific but high intraspecific phenotypic and genetic diversity was found among Neocladocystis spp. Phylogenetic inference based on partial 28S rDNA sequences revealed a sister group relationship for two of the newly erected genera and their close relatedness to the widely distributed genus Acanthostomum Looss, 1899. CONCLUSIONS: The present study provides the first comprehensive characterisation of the digenean diversity in a fish family from Lake Tanganyika which will serve as a baseline for future explorations of the lake's digenean fauna. Our study highlights the importance of employing an integrative approach for revealing the diversity in this unique host-parasite system.

Molecular circumscription of new species of Gyrocotyle Diesing, 1850 (Cestoda) from deep-sea chimaeriform holocephalans in the North Atlantic.

Chimaeras, or ratfishes, are the only extant group of holocephalan fishes and are the sole host group of gyrocotylidean cestodes, which represent a sister group of the true tapeworms (Eucestoda). These unique, non-segmented cestodes have been known since the 1850s and multiple species and genera have been erected despite a general agreement that the delineation of species on the basis of morphology is effectively impossible. Thus, in the absence of molecular studies, the validity of gyrocotylid taxa and their specific host associations has remained highly speculative. Here we report the presence of Gyrocotyle spp. from rarely-caught deep-sea chimaeras collected in the North-East Atlantic, and describe two new species: G. haffii n. sp. from the bent-nose chimaera, Harriota raleighana Goode & Bean, and G. discoveryi n. sp. from the large-eyed rabbit fish, Hydrolagus mirabilis (Collett). Nuclear ribosomal sequence data were generated for individual parasites taken from different host species collected on different dates and from different localities and were combined with previously published sequences. Phylogenetic analyses supported the recognition of independent lineages and clusters, indicative of species, but were indecisive in recovering the root of the tree in analyses that included non-gyrocotylid outgroup taxa. The molecular data reveal variation not reflected in morphology and point to a complex picture of genetic divergence shaped by both isolation and migration in the deep-sea environment.

Bucephalus damriyasai n. sp. (Digenea: Bucephalidae) from the blacktip trevally Caranx heberi (Bennett) (Perciformes: Carangidae) off Bali, Indonesia.

The new species Bucephalus damriyasai n. sp. is described from Caranx heberi (Bennett) from off Bali, Indonesia. It can be distinguished from other Bucephalus spp. recorded from carangid hosts by its narrow elongate body shape and the relatively long distance between the rhynchus and the vitellarium, as well as other features distinguishing it from individual species. The most similar species are differentiated from B. damriyasai n. sp. as follows: B. carangis Yamaguti, 1970 has a much greater length, the rhynchus is smaller and the cirrus-sac is small, not always reaching to the posterior testis; B. fragilis Velasquez, 1959 is a tiny species, the pre-vitelline distance is short and the caecum is saccular; B. gorgon (Linton, 1905) is much longer and relatively broader, the uterus reaches distinctly anterior to the vitellarium and the rhyncheal tentacles appear more complex; B. labracis Paggi & Orecchia, 1965 is distinctly longer, slightly broader, with a slightly larger rhynchus, and has shorter pre-uterine and pre-mouth distances; B. paraheterotentaculatus Velasquez, 1959 is much longer, relatively rather broad, the rhynchus is said to bear 21 tentacles, the post-testicular region and cirrus-sac reach are longer and the caecum is described as saccular; B. sphyraenae Yamaguti, 1952 is longer, slightly broader, the uterus reaches anteriorly to the vitellarium and the caecum is claviform and oriented anteriorly; B. margaritae Ozaki & Ishibashi, 1934 (syn. B. varicus Manter, 1940) is relatively squat, has shorter pre-vitelline and pre-mouth distances and a longer post-testicular distance and cirrus-sac reach; B. yamagutii Gupta & Singh, 1985 is broader, with a relatively short pre-vitelline distance, the caecum extends anteriorly to the pharynx, but not posteriorly and the rhynchus is said to carry five tentacles. The distinctive features of B. damriyasai n. sp. are compared with those of all other marine Bucephalus spp. in a table. The number of bucephalid trematodes known from Indonesian waters is now 13, two of them await further identification. They have been described from the fish families Carangidae, Platycephalidae, Sciaenidae, Serranidae and Sphyraenidae.

Ultrastructure of mature spermatozoa of three Bucephalidae (Prosorhynchus longisaccatus, Rhipidocotyle khalili and Bucephalus margaritae) and phylogenetic implications.

We describe here the mature spermatozoa of three species of bucephalids, namely Bucephalus margaritae, Rhipidocotyle khalili and Prosorhynchus longisaccatus. This study provides the first ultrastructural data on the genera Bucephalus and Rhipidocotyle and enabled us to confirm the model of the mature spermatozoon in the Bucephalinae. The spermatozoon exhibits two axonemes with the 9 + "1" pattern of the Trepaxonemata, one of which is very short, lateral expansion, external ornamentation of the plasma membrane located in the anterior extremity of the spermatozoon and associated with cortical microtubules, spine-like bodies, a mitochondrion, and a nucleus. The maximum number of cortical microtubules is located in the anterior part of the spermatozoon. However, more studies are needed to elucidate if spine-like bodies are present in all the Bucephalinae or not. In the Prosorhynchinae, the mature spermatozoon exhibits a similar ultrastructural pattern. Some differences are observed, particularly the axoneme lengths and the arrangement of the spine-like bodies. The posterior extremity of the spermatozoon in the Bucephalinae exhibits only the nucleus, but prosorhynchines have microtubules.

Lepotrema Ozaki, 1932 (Lepocreadiidae: Digenea) from Indo-Pacific fishes, with the description of eight new species, characterised by morphometric and molecular features.

We review species of the genus Lepotrema Ozaki, 1932 from marine fishes in the Indo-West Pacific. Prior to the present study six species were recognised. Here we propose eight new species on the basis of combined morphological and molecular analysis: Lepotrema acanthochromidis n. sp. ex Acanthochromis polyacanthus from the Great Barrier Reef (GBR); Lepotrema hemitaurichthydis n. sp. ex Hemitaurichthys polylepis and H. thompsoni from Palau and French Polynesia; Lepotrema melichthydis n. sp. ex Melichthys vidua from Palau and the GBR; Lepotrema amansis n. sp. ex Amanses scopas from the GBR; Lepotrema cirripectis n. sp. ex Cirripectes filamentosus, C. chelomatus and C. stigmaticus from the GBR; Lepotrema justinei n. sp. ex Sufflamen fraenatum from New Caledonia; Lepotrema moretonense n. sp. ex Prionurus microlepidotus, P. maculatus and Selenotoca multifasciata from Moreton Bay; and Lepotrema amblyglyphidodonis n. sp. ex Amblyglyphidodon curacao and Amphipron akyndynos from the GBR. We also report new host records and provide novel molecular data for two known species: Lepotrema adlardi Bray, Cribb & Barker, 1993 and Lepotrema monile Bray & Cribb, 1998. Two new combinations are formed, Lepotrema cylindricum (Wang, 1989) n. comb. (for Preptetos cylindricus) and Lepotrema navodonis (Shen, 1986) n. comb. (for Lepocreadium navodoni). With the exception of a handful of ambiguous records, the evidence is compelling that the host-specificity of species in this genus is overwhelmingly oioxenous or stenoxenous. This renders the host distribution in three orders and ten families especially difficult to explain as many seemingly suitable hosts are not infected. Multi-loci molecular data (ITS2 rDNA, 28S rDNA and cox1 mtDNA) demonstrate that Lepotrema is a good generic concept, but limited variability in sequence data and differences in phylogenies produced for different gene regions make relationships within the genus difficult to define.

Two new species of Bacciger Nicoll, 1914 (Trematoda: Faustulidae) in species of Herklotsichthys Whitley (Clupeidae) from Queensland waters.

Two new species of Bacciger Nicoll, 1914 (Faustulidae) are described infecting clupeids collected from the waters off Queensland, Australia; Bacciger minor n. sp. is described from Herklotsichthys castelnaui (Ogilby) in Moreton Bay, southern Queensland and Bacciger major n. sp. is described from Herklotsichthys quadrimaculatus (Rüppell) collected off Lizard Island, on the northern Great Barrier Reef. The two species both differ from previously described species of Bacciger in the combination of their generally elongate bodies, an entire rather than deeply lobed ovary, vitelline follicles that reach to at least the intestinal bifurcation, instead of restricted to further posteriorly but principally distributed in the hindbody, and intestinal caeca extending posteriorly well past the ventral sucker. The two new species have non-overlapping size ranges and differ in their sucker ratios, the distribution of the vitelline follicles and in the shape of the cirrus-sac. ITS2 and 28S rDNA sequence data distinguish the two new species unambiguously. Phylogenetic analysis of available 28S data show they are most closely related to Pseudobacciger cheneyae Sun, Bray, Yong, Cutmore & Cribb, 2014, also recorded off Lizard Island. These are the first faustulids reported from species of Herklotsichthys Whitley, but overall members of the Clupeidae undoubtedly harbours the richest faustulid fauna of any fish family. Baccigeroides ovatus (Price, 1934) n. comb. is proposed for Bacciger ovatus (Price, 1934) Bray & Gibson, 1980 (syn. B. opisthonema Nahhas & Cable, 1964) based on the position of the genital pore being far anteriorly removed from the ventral sucker.

Lepocreadiidae Odhner, 1905 and Aephnidiogenidae Yamaguti, 1934 (Digenea: Lepocreadioidea) of fishes from Moreton Bay, Queensland, Australia, with the erection of a new family and genus.

Digeneans of the lepocreadioid families Lepocreadiidae Odhner, 1905 and Aephnidiogenidae Yamaguti, 1934 from Moreton Bay, off southern Queensland, Australia, are recorded, along with the erection of a new family, Gibsonivermidae. Molecular data were generated for all representatives of these families collected during this study and a phylogram for members of the superfamily was generated based on the partial 28S rDNA dataset, placing these species in context with those previously sequenced. This phylogenetic analysis demonstrates that the monotypic Gibsonivermis Bray, Cribb & Barker, 1997 is isolated from all other lepocreadioids and supports the erection of Gibsonivermidae n. fam., which is defined morphologically, based particularly on the uniquely elongated male terminal genitalia, the distribution of the uterus in the forebody and the presence of a uroproct. Mobahincia teirae n. g., n. sp. is reported from Platax teira (Forsskål) in Moreton Bay and off Heron Island and New Caledonia. Recognition of this new genus is based on molecular results and the combination of caeca abutting the posterior body wall and the lack of an anterior body scoop or flanges. The following lepocreadioid species are reported from Moreton Bay for the first time: Bianium arabicum Sey, 1996 in Lagocephalus lunaris (Bloch & Schneider), Diploproctodaeum cf. monstrosum Bray, Cribb & Justine, 2010 in Arothron hispidus (Linnaeus), Multitestis magnacetabulum Mamaev, 1970 and Neomultitestis aspidogastriformis Bray & Cribb, 2003 in Platax teira and Opechona austrobacillaris Bray & Cribb, 1998 in Pomatomus saltatrix (Linnaeus). Bianium plicitum (Linton, 1928) is reported from Torquigener squamicauda (Ogilby) for the first time. Sequences of newly collected specimens of Austroholorchis sprenti (Gibson, 1987) indicate that the species forms a clade with other members of the Aephnidiogenidae, agreeing with its morphology. The phylogenetic status of all newly sequenced species is discussed.

Morphological and molecular characterisation of digenean parasites of the Galápagos sheephead Semicossyphus darwini (Jenyns) with the re-description of Labrifer secundus Manter, 1940 (Lepidapedidae) from the Humboldt Current Large Marine Ecosystem.

The Humboldt Current Large Marine Ecosystem (HCLME) is recognised as one of the largest and most productive marine ecosystems. The estimated number of teleost fish species for the Chilean coast influenced by the HCLME reaches c.1,030 but digeneans have been reported for 39 teleost species, i.e. less than 4% of the potential hosts. During a survey of parasites of the Galápagos sheephead wrasse Semicossyphus darwini (Jennyns) (Perciformes: Labridae) from off northern Chile, we obtained representatives of three digenean species, Helicometrina nimia Linton, 1910 (Opecoelidae), Proctoeces humboldti George-Nascimento & Quiroga, 1983 (Fellodistomidae) and Labrifer secundus Manter, 1940 (Lepidapedidae). Labrifer secundus, originally described from Semicossyphus pulcher (Ayres, 1854) off the coast of Baja California, Mexico is re-described. Helicometrina nimia is a common parasite from littoral fishes in the HCLME. Semicossyphus darwini is a new host for these three digenean species.

Three members of Opisthomonorcheides Parukhin, 1966 (Digenea: Monorchiidae) from carangid fishes (Perciformes) from Indonesia, with a review of the genus.

Three species of Opisthomonorcheides Parukhin, 1966 are reported for the first time from Indonesian waters: O. pampi (Wang, 1982) Liu, Peng, Gao, Fu, Wu, Lu, Gao & Xiao, 2010 and O. ovacutus (Mamaev, 1970) Machida, 2011 from Parastromateus niger (Bloch), and O. decapteri Parukhin, 1966 from Atule mate (Cuvier). Both O. pampi and O. ovacutus can now be considered widespread in the Indo-Pacific region, with earlier records of these species being from Fujian Province, China and Penang, Malaysia, respectively. We redescribe O. decapteri from one of its original hosts, Atule mate, off New Caledonia, and report this species from Jakarta Bay, Indonesia, extending its range throughout the Indian Ocean into the south-western Pacific. All three species possess a genital atrium that is long, sometimes very long, and a genital pore that is located in the forebody. This validates the interpretation that the original description was erroneous in reporting the genital pore in the hindbody, well posterior to the ventral sucker. These observations verify the synonymy of Retractomonorchis Madhavi, 1977 with Opisthomonorcheides. A major discrepancy between the species of Opisthomonorcheides is that some are described with the uterus entering the terminal organ laterally and some with it entering terminally; this feature needs further analysis. Based on the length of the genital atrium and the posterior extent of the vitellarium, the 27 species of Opisthomonorcheides considered valid can be divided into four groups. Among the 53 host records analysed, the families Carangidae (53% of records), Stromateidae (17%) and Serranidae (5.7%) are the most common; the reports are overwhelmingly from members of the Perciformes (91%), with further records in the Clupeiformes (5.7%), Gadiformes (1.9%) and Pleuronectiformes (1.9%). Two fish genera (Parastromateus Bleeker and Pampus Bonaparte) dominate the recorded hosts, with the black pomfret Parastromateus niger harbouring six species, the silver pomfret Pampus argenteus (Euphrasen) harbouring six, and the Chinese silver pomfret P. chinensis (Euphrasen) two. A host-parasite checklist is presented. We discuss the host-specificity of members of the genus, questioning some records such as that of O. decapteri in a deep-sea macrourid. We also comment on the morphological similarity, but phylogenetic distance, between the various Pomfret species, advancing the possibility that a series of host misidentifications has occurred. Sequences of the ITS2 rDNA gene generated for O. pampi and O. ovacutus are briefly discussed and molecular data are lodged in the GenBank database.