Morphological and Molecular Characterisation of a New Species of Parastrongyloides (Rhabditida: Strongyloididae) from the Short-Beaked Echidna Tachyglossus aculeatus from Western Australia.

INTRODUCTION: A new species of the nematode genus Parastrongyloides Morgan, 1928 was found in the caecum of six short-beaked echidnas Tachyglossus aculeatus (Shaw, 1792) collected from southwestern Australia between August 1964 and March 2020. METHODS: Specimens were prepared for microscopic examination as temporary wet mounts, measurements were made using an Olympus DP71 camera with cellSens standard software, figures were drawn using a drawing tube and light micrographs taken. DNA was extracted using a Qiagen blood and tissue kit, amplified targeting the COX1 gene region. Sequences obtained were analysed and edited using Geneious v.8.1 and aligned to existing sequences published in Genbank using MUSCLE. RESULTS: Parastrongyloides spratti n. sp. can be distinguished from all other species of Parastrongyloides in having the male caudal papillae arranged as a single median dome-shaped pre-cloacal papilla, three tiny pairs of ventral papillae immediately pre-cloacal, a tiny ventral pair of papillae post-cloacal and the female with four to five pairs of dorsoventral papillae immediately anterior to the vulva. A revised key to the species of Parastrongyloides found in Australia is given. Sequence analysis of the COX1 gene corroborated the species status of P. spratti. DISCUSSION: Morphological and molecular analyses support the status of P. spratti as a new species. Parastrongyloides may have an ancient origin in the Australian portion of Gondwanaland.

A Survey of the Nematode Parasites of the Short-beaked Echidna Tachyglossus aculeatus (Monotremata: Tachyglossidae) from Southwestern Australia with the Description of a New Subfamily, Genus and Species of the Subuluridae Travassos, 1914 (Nematoda: Ascaridida).

INTRODUCTION: Nematodes were found in the digestive tracts of 15 short-beaked echidnas Tachyglossus aculeatus (Shaw, 1792) collected from southwestern Australia between August 1964 and March 2020. METHODS: Specimens were prepared for microscopic examination as temporary wet mounts, measurements were made, figures prepared using a drawing tube and light micrographs taken. All nematodes were identified to at least genus level and a bootstrap analysis of the helminth community was carried out. RESULTS: Two previously described species, one species identified to genus and one new nematode species were recovered, including Nicollina ridei (Nicollinidae), Parapharyngodon anomalus (Pharyngodonidae), Parastrongyloides sp. (Strongyloididae) and Echidnonema coronorum n. g., n. sp. (Subuluridae, Echidnonematinae n. sf.). Echidnonema coronorum n. sp. can be distinguished from all other subulurids in having a mouth encircled by six leaf-like elements separated by six small pointed elements. The buccal complex is also unique to this species and is composed of three parts, including an anterior buccal capsule and a posterior pharyngeal portion divided into two; the proximal part contains lobes which are ornamented with numerous irregular teeth. A bootstrap estimate of species richness of 99.9% indicated that there were few, if any, additional species to be discovered in the southwestern Australian population of short-beaked echidnas. CONCLUSION: Morphological analysis supports the status of E. coronorum as a new species and the erection of the Echidnonematinae as a new subfamily to accommodate it. The helminth community of the population of short-beaked echidnas studied appears to be depauperate and contains species unique to the region.

Monocotylids (Monogenoidea) infecting elasmobranchs in Moreton Bay, Queensland, Australia, with descriptions of Calicotyle cutmorei n. sp. (Calicotylinae) and Dendromonocotyle raiae n. sp. (Monocotylinae).

Eighteen monocotylid species were collected from elasmobranchs during surveys of the parasites of fishes of Moreton Bay, Queensland, Australia. Two new species, Calicotyle cutmorei n. sp. (Calicotylinae) from Carcharhinus sorrah (Valenciennes) (Carcharhiniformes) and Dendromonocotyle raiae n. sp. (Monocotylinae) from Hemitrygon fluviorum (Ogilby) and Neotrygon trigonoides (Castelnau) (both Myliobatiformes) are described and illustrated. Six new faunal records for Moreton Bay are reported: Thaumatocotyle australensis Beverley-Burton & Williams, 1989 (Merizocotylinae) from Maculabatis toshi (Whitley) (Myliobatiformes); Monocotyle corali Chisholm, 1998 (Monocotylinae) from Pastinachus ater (Macleay) (Myliobatiformes); Neoheterocotyle rhynchobatis (Tripathi, 1959) Chisholm, 1994 (Heterocotylinae) from Glaucostegus typus (Anonymous [Bennett]) and Aptychotrema rostrata (Shaw) (both Rhinopristiformes); and Decacotyle elpora Marie & Justine, 2005 (Decacotylinae), Dendromonocotyle torosa Chisholm & Whittington, 2004 (Monocotylinae), and Clemacotyle australis Young, 1967 (Monocotylinae) from Aetobatus ocellatus (Kuhl) (Myliobatiformes). Maculabatis toshi is a new host record for T. australensis, and A. rostrata is a new host record for N. rhynchobatis. Ten species previously recorded from Moreton Bay were collected: Monocotyle caseyae Chisholm & Whittington, 2005 (Monocotylinae) and Heterocotyle whittingtoni Chisholm & Kritsky, 2020 (Heterocotylinae) from M. toshi; Monocotyle sp. A of Chisholm (1998a) (Monocotylinae) from H. fluviorum; Dendromonocotyle kuhlii Young, 1967 and Monocotyle kuhlii Young, 1967 (both Monocotylinae) from N. trigonoides; Thaumatocotyle cf. pseudodasybatis Hargis, 1955 (Merizocotylinae), Empruthotrema kearni Whittington, 1990 (Merizocotylinae) and Decacotyle octona Young, 1967 (Decacotylinae) from A. ocellatus; and Mycteronastes icopae (Beverley-Burton & Williams, 1989) Kearn & Beverley-Burton, 1990 (Merizocotylinae) and Troglocephalus rhinobatidis Young, 1967 (Dasybatotreminae) from G. typus.

Heterocotyle whittingtoni n. sp. (Monogenea: Monocotylidae) from the gills of the black-spotted whipray, Maculabatis toshi (Whitley) (Myliobatiformes: Dasyatidae), collected in coastal waters of Queensland, Australia.

Heterocotyle whittingtoni n. sp. (Monogenea: Monocotylidae) is described from the gills of the black-spotted whipray Maculabatis toshi (Whitley) (Dasyatidae) collected from Moreton Bay near Dunwich and Peel Island, and from the eastern Gulf of Carpentaria off Weipa, Queensland, Australia. Heterocotyle whittingtoni n. sp. has a single sinuous ridge surmounting the haptoral septa and the male copulatory organ lacks an accessory piece. The new species can be distinguished from the two other Heterocotyle species that have this combination of characters by the distal portion of the male copulatory organ which is slightly flared with uniquely thickened walls and by the morphology of the testis. The identity of the host of H. whittingtoni n. sp. is discussed. We confirm that the host of the monocotylids Dendromonocotyle lasti Chisholm & Whittington, 2005 and Monocotyle caseyae Chisholm & Whittington, 2005 originally identified as "Himantura sp." was M. toshi.

Septitrema lichae n. g., n. sp. (Monogenea: Monocotylidae) from the nasal tissues of the deep-sea kitefin shark, Dalatias licha (Bonnaterre) (Squaliformes: Dalatiidae), off Algeria.

Septitrema lichae n. g., n. sp. (Monogenea: Monocotylidae: Merizocotylinae) is described from the nasal tissue of the deep-sea kitefin shark, Dalatias licha (Bonnaterre) (Dalatiidae) collected off Algiers, Algeria. The new genus is distinguished from the other genera in the subfamily by the number and arrangement of the loculi on the haptor having one central and seven peripheral loculi. The diagnosis of the Merizocotylinae is amended to accommodate this species and a key to the genera of the Merizocotylinae is provided. Terminology of the haptoral loculi in the Merizocotylinae and the status of some of the genera in the subfamily are also discussed.

Acanthocephalans from Australian elasmobranchs (Chondrichthyes) with a description of a new species in the genus Gorgorhynchus Chandler, 1934 (Rhadinorhynchidae).

Gorgorhynchus occultus n. sp. is described from Sutorectus tentaculatus (Peters) (Orectolobidae) collected off Bunbury, Western Australia in 1986. The new species differs from all other species of Gorgorhynchus Chandler, 1934 by having a suite of characters including a proboscis hook formula of 18-20 rows of 8-9 hooks, a well-developed neck, irregular circles of small spines in a single anterior field, the male reproductive system limited to the posterior quarter of the trunk and three cement glands. In a survey of 284 sharks collected between 2015 and 2018 from 10 localities in Australian waters, 11 individuals were infected with acanthocephalan cystacanths. One individual of Sphyrna mokarran (Rupell) (Sphyrnidae) was infected with Corynosoma cetaceum Johnston & Best, 1931. Serrasentis sagittifer (Linton, 1889) (Rhadinorhynchidae) was found in five individuals of S. mokarran, four individuals of Syphyrna lewini (Griffith & Smith) and one individual of Carcharhinus coatesi (Whitley) (Carcharhinidae). These infections may be accidental because it has been suggested that acanthocephalans cannot tolerate the high levels of urea used by marine and esturine elasmobranchs for osmoregulation. The two most common host species examined, S. mokarran and S. lewini had the highest intensities and prevalences of infection with S. sagittifer. Although more individuals of S. lewini were examined, S. mokarran had the higher prevalence of infection.

A new species of Acanthocotyle Monticelli, 1888 (Platyhelminthes: Monogenea: Acanthocotylidae) from the ventral skin of the banded stingaree, Urolophus cruciatus (Lacépède, 1804), from Tasmania, Australia.

Acanthocotyle urolophi sp. nov. is described from the skin of the banded stingaree, Urolophus cruciatus (Lacépède, 1804). This is the first acanthocotylid to be described from Australian waters. Acanthocotyle urolophi sp. nov. is distinguished from other species of Acanthocotyle by a combination of the number of vitelline follicles 38 (33-46) and the number of rows 35 (32-37) of sclerites on the pseudohaptor. In addition, Acanthocotyle urolophi sp. nov. has no germarial appendix and no uterine "arm". A uterine receptaculum seminis was not identified in whole mounts. There is no penis papilla and no penis sclerite associated with the male reproductive opening. A brief description of the larva is provided. The diagnosis of the Acanthocotylidae Price, 1936 is amended and we review the Allacanthocotylinae Yamaguti, 1963, Lophocotylinae Yamaguti, 1963 and Pseudacanthocotylinae Yamaguti, 1963. We deem that these subfamilies are invalid and that the family now comprises only the subfamily Acanthocotylinae and the genus Acanthocotyle. The validity of species previously assigned to the Acanthocotylidae (sensu Yamaguti, 1963) is discussed and a key to what we consider to be the valid species in the family is also provided.

Electrocotyle whittingtoni n. gen., n. sp. (Monogenea: Monocotylidae: Heterocotylinae) from the gills of a captive onefin electric ray, Narke capensis (Narkidae) at Two Oceans Aquarium, Cape Town, South Africa.

Electrocotyle whittingtoni n. gen., n. sp. (Monogenea: Monocotylidae) is described from the gills of a captive female onefin electric ray, Narke capensis, collected for exhibition at Two Oceans Aquarium in Cape Town, South Africa. Electrocotyle n. gen. is most similar to the heterocotyline genera Heterocotyle and Potamotrygonocotyle but could not be accommodated easily in either of these groups. The new genus is characterised by a haptor with one central and eight peripheral loculi, four unsclerotised structures on the dorsal surface of the haptor, a single unsclerotised non-sinous ridge on the ventral surface of the haptoral septa, large hamuli with a long handle and reduced guard, a vagina with sclerotised walls, and tetrahedral eggs. Molecular phylogenetic analyses based on 28S sequences strongly support the separate genus status of Electrocotyle n. gen and thus support our morphological conclusion. The Heterocotylinae is amended to accommodate the new genus, and the new species is fully described and illustrated herein. This is the first record of a monocotylid from the Narkidae. Electrocotyle whittingtoni n. gen. n. sp. is considered potentially pathogenic given its negative impact on the health of its captive host kept in the quarantine facility at Two Oceans Aquarium.

A new species of Dendromonocotyle Hargis, 1955 (Monogenea: Monocotylidae) from the skin of Zearaja chilensis (Guichenot) (Rajiformes: Rajidae) from the Argentine Sea.

Dendromonocotyle rajidicola n. sp. is described from the dorsal surface of the yellownose skate Zearaja chilensis (Guichenot) (Rajiformes) caught on the Argentine shelf. Dendromonocotyle rajidicola n. sp. can be distinguished from the other 17 species in the genus by the morphology of the distal portion of the male copulatory organ and by the unique morphology of the sclerotised proximal portion of the vagina. This is the first species of Dendromonocotyle to be described from a host in the Rajiformes and also the first record of this genus in the southwestern Atlantic Ocean.

On the morphology and taxonomy of Griphobilharzia amoena Platt and Blair, 1991 (Schistosomatoidea), a dioecious digenetic trematode parasite of the freshwater crocodile, Crocodylus johnstoni, in Australia.

Griphobilharzia amoena Platt and Blair, 1991 was originally described as a dioecious trematode, parasitic in the circulatory system of the Australian freshwater crocodile, Crocodylus johnstoni, with the female completely enclosed in a gynecophoric chamber of the male and the 2 worms oriented anti-parallel to each other. A recent publication questions the original description, arguing that G. amoena is monoecious and, as a consequence, the species was transferred to Vasotrema Stunkard, 1928 (Spirorchiidae) as Vasotrema amoena n. comb. We provide photomicrographic evidence that the original description of G. amoena is correct and that Griphobilharzia Platt and Blair, 1991, is a valid monotypic genus containing G. amoena. An accurate understanding of the anatomy of G. amoena is not trivial and has implications for revealing the complex origins and evolution of the dioecious condition within the Schistosomatoidea.

Septesinus gibsoni n. g., n. sp. (Monocotylidae: Heterocotylinae), from the gills of Himantura walga (Dasyatidae) off Sarawak, Borneo.

Septesinus gibsoni n. g., n. sp. (Monocotylidae: Heterocotylinae) is described from the gills of the dwarf whipray Himantura walga (Müller & Henle) collected in marine waters off Sarawak (Borneo), Malaysia. Septesinus n. g. is distinguished from other genera in the Monocotylidae by a combination of characters, including a haptor with one central and seven peripheral loculi, the presence of a highly sinuous ridge surmounting all haptoral septa, four rounded accessory structures on the dorsal surface of the haptor, and the anterior region with two pairs of anteromedian and three pairs of anterolateral gland-duct openings. Septesinus n. g. is accommodated in the Heterocotylinae. Septesinus gibsoni n. sp. is described and fully illustrated, and a key to the genera of Heterocotylinae is provided. The composition of the ridges surrounding the mouth of a number of heterocotyline species and their usefulness as a taxonomic character are examined. The identity of four specimens of Monocotyle Taschenberg, 1878, also recovered from the gills of this host species, is discussed.

Three new species of Merizocotyle Cerfontaine, 1894 (Monogenea: Monocotylidae) from the nasal tissues of dasyatid rays collected off Malaysian and Indonesian Borneo.

Three new species of Merizocotyle Cerfontaine, 1894 (Monogenea: Monocotylidae) are described from the nasal tissues of stingrays collected off Borneo. Merizocotyle macrostrobus n. sp. is described from the dwarf whipray Himantura walga (Müller & Henle) collected in shallow waters off Sematan, Sarawak, Malaysia. This species can be distinguished from the other members of the genus by the morphology of the sclerotised male copulatory organ, which is long with many twists and loops. The vaginae of this species are also long and looped. Merizocotyle papillae n. sp. is described from the roughnose stingray Pastinachus solocirostris Last, Manjaji & Yearsley collected off Sematan and Mukah, Sarawak, Malaysia. It is distinguished from the other species of Merizocotyle by the morphology of the male copulatory organ, which is a sclerotised tube that expands slightly and then tapers at the distal end, and by the presence of papillae on the dorsal edge of the haptor. Merizocotyle rhadinopeos n. sp. is described from the whitenose whip ray Himantura uarnacoides (Bleeker) collected off Manggar, East Kalimantan, Indonesia. It can be differentiated by the male copulatory organ, which is a short, narrow, curved, sclerotised tube tapering distally, and the path of the ovary, which runs anteriorly to the base of the oötype. We also provide details of new host and/or locality records for M. australensis (Beverley-Burton & Williams, 1989) Chisholm, Wheeler & Beverley-Burton, 1995, M. icopae Beverley-Burton & Williams, 1989 and M. pseudodasybatis (Hargis, 1955) Chisholm, Wheeler & Beverley-Burton, 1995.

A new species of Heterocotyle Scott, 1904 (Monogenea: Monocotylidae) from the gills of Dasyatis guttata (Dasyatidae) in southwestern Atlantic waters off Rio de Janeiro, Brazil.

Heterocotyle sulamericana n. sp. is described from the gills of Dasyatis guttata (Bloch & Schneider) caught off the coast of Brazil near Rio de Janeiro. This species can be distinguished from all other members of Heterocotyle Scott, 1904 by a combination of the morphology of the male copulatory organ, which is a short, slightly curved, sclerotised tube with no accessory piece, and the haptor, which has a single ridge surmounting all septa. This is the first Heterocotyle species to be described from the southwestern Atlantic.

A new species of Neoheterocotyle Hargis, 1955 (Monogenea: Monocotylidae) from the gills of Rhinobatos annulatus Müller & Henle (Rhinobatidae) off the southern tip of Africa.

Neoheterocotyle robii n. sp. is described from the gills of four female Rhinobatos annulatus Müller & Henle caught as bycatch during routine demersal research trawls off the Southern Cape coast of South Africa. The new species can be distinguished from all other members of Neoheterocotyle Hargis, 1955 by the morphology of the accessory piece associated with the male copulatory organ, the presence of a distinct horseshoe-shaped muscle associated with the male copulatory organ and the presence of a sclerotised structure in the proximal portion of the vagina. This is the first Neoheterocotyle species described from South African waters.

Three Dendromonocotyle species (Monogenea: Monocotylidae) reported from captive rays, including D. lotteri sp. n. from Himantura gerrardi (Elasmobranchii: Dasyatidae) in the public aquarium at the Atlantis resort, Dubai.

Dendromonocotyle lotteri sp. n. is described from the dorsal skin surface of the stingray Himantura gerrardi (Gray) on exhibit in the public aquarium at the Atlantis resort in Dubai. It is differentiated from all other Dendromonocotyle species by the unique morphology of the distal portion of the sclerotised male copulatory organ. Dendromonocotyle lotteri is the second representative in the genus with 56 marginal haptoral papillae having a papillae to loculus association represented numerically as 6-6-8-8. We found Dendromonocotyle colorni Chisholm, Whittington et Kearn, 2001 on the same host specimens at the Atlantis resort public aquarium and Dendromonocotyle kuhlii Young, 1967 on Neotrygon kuhlii (Müller et Henle) kept at Burgers' Zoo Aquarium in Arnhem, The Netherlands. Supplemental information is provided for both D. colorni and D. kuhlii. The presence of Dendromonocotyle infections in public aquaria and host specificity are discussed. A key to the 17 species of Dendromonocotyle is also provided.

Malalophus jensenae n. g., n. sp. (Monogenea: Monocotylidae) from the gills of Aetomylaeus vespertilio (Myliobatidae) off northern Australia.

Malalophus jensenae n. g., n. sp. is described from the gills of the ornate eagle ray Aetomylaeus vespertilio (Bleeker) collected off the eastern coast of the Gulf of Carpentaria, northern Queensland. The new genus is similar to Heliocotyle Neifar, Euzet & Ben Hassine, 1999, with which it shares a haptor bearing seven peripheral loculi and a single dorsal haptoral accessory structure. M. jensenae can be distinguished from species of Heliocotyle by the presence of numerous sclerotised sinuous ridges covering the ventral surfaces of the peripheral loculi of the haptor. It also lacks pseudosepta which are present on the haptor of Heliocotyle species. This is the first published record of a monogenean from an elasmobranch in the Gulf of Carpentaria, Australia.

Looks can deceive: molecular phylogeny of a family of flatworm ectoparasites (Monogenea: Capsalidae) does not reflect current morphological classification.

The morphological based taxonomy of highly derived parasite groups is likely to poorly reflect their evolutionary relationships. The taxonomy of the monogenean family Capsalidae, which comprises approximately 180 species of flatworm parasites that predominantly attach to external surfaces of chondrichthyan and teleost fishes, is based mainly on six morphological characters. The phylogenetic history of the family is largely unknown. We reconstructed the phylogenetic relationships of 47 species in 20 genera from eight of the nine subfamilies, from nucleotide sequences of three unlinked nuclear genes, 28S ribosomal RNA, Histone 3 and Elongation Factor 1 alpha. Our phylogeny was well corroborated, with 75% of branches receiving strong support from both Bayesian posterior probabilities and maximum likelihood bootstrap proportions and all nodes showed positive partitioned likelihood support for each of the three genes. We found that the family was monophyletic, with the Gyrodactylidae and Udonellidae forming the sister group. The Capsalinae was monophyletic, however, our data do not support monophyly for the Benedeniinae, Entobdellinae and Trochopodinae. Monophyly was supported for Capsala, Entobdella, Listrocephalos, Neobenedenia and Tristoma, but Benedenia and Neoentobdella were polyphyletic. Comparisons of the distribution of character states for the small number of morphological characters on the molecular phylogeny show a high frequency of apparent homoplasy. Consequently the current morphological classification shows little correspondence with the phylogenetic relationships within the family.

Comparative phylogeography reveals host generalists, specialists and cryptic diversity: Hexabothriid, microbothriid and monocotylid monogeneans from rhinobatid rays in southern Australia.

The phylogeography and host specificity of three monogenean species infecting different sites on the southern fiddler ray, Trygonorrhina fasciata (Rhinobatidae) in South Australia (SA) were studied: Branchotenthes octohamatus (Hexabothriidae: gills), Calicotyle australis (Monocotylidae: cloaca) and Pseudoleptobothrium aptychotremae (Microbothriidae: skin). Five rhinobatid species (Aptychotrema vincentiana, T. fasciata, Trygonorrhina sp. A, Aptychotrema rostrata and Rhinobatos typus) with distributions spanning west, south and east Australian coastal waters, were surveyed for monogeneans resembling the three species documented from T. fasciata in SA. The identities of hosts and parasites collected were investigated using the mitochondrial genes ND4 and Cytochrome b (cytb), respectively, in addition to the nuclear marker, Elongation factor 1-alpha (EF1a) for Pseudoleptobothrium. Genetic analyses confirmed that B. octohamatus is geographically widespread and displays little genetic structure, suggesting high levels of gene flow. It was collected from four rhinobatid species throughout its distribution and is not, therefore, host specific. For C. australis, genetic analyses revealed two discrete populations with a genetic divergence of ∼4%, one population occurring west of Bass Strait on two sympatric host species and the other population on the east coast, also occurring on sympatric host species. Similarly, for Pseudoleptobothrium, specimens collected west of Bass Strait were genetically distinct (∼3.5%) from those collected to the east. However, on the east coast, a third Pseudoleptobothrium population was revealed, separated by a genetic distance of >11%, indicating a morphologically cryptic species. Host preferences were indicated for each Pseudoleptobothrium lineage. These genetic discoveries are discussed in relation to life history characteristics of each monogenean species, highlighting the value of phylogeographic analyses to understand the parasite-host relationship.

A redescription of Calicotyle australis Johnston, 1934 (Monogenea: Monocotylidae) from the type-host Trygonorrhina fasciata (Rhinobatidae) off Adelaide, South Australia, including descriptions of live and silver stained larvae.

Calicotyle australis Johnston, 1934 (Monogenea Monxocotylidae) is redescribed from the cloaca of the type-host, the southern fiddler ray Trygonorrhina fasciata (Rhinobatidae) off Adelaide, South Australia. Lobed glands joining the oötype are reported for the first time and may be characteristic of the genus. The presence of an appendix associated with the seminal vesicle in C. australis, previously reported as absent, is confirmed. The anatomy of the oncomiracidium of C. australis is described from observations of live larvae, and the number and distribution of ciliated epidermal cells and sensilla, revealed by silver staining larvae, is also described. Use of larval characters to distinguish between species of Calicotyle Diesing, 1850 and other closely related monocotylids is discussed.

Branchotenthes octohamatus sp. n. (Monogenea: Hexabothriidae) from the gills of the southern fiddler ray, Trygonorrhina fasciata (Rhinobatidae) in South Australia: description of adult and larva.

Branchotenthes octohamatus sp. n. (Monogenea: Hexabothriidae) is described from the gills of the southern fiddler ray, Trygonorrhina fasciata Müller et Henle (Elasmobranchii: Rhinobatidae), off Adelaide, South Australia. It is distinguished from the type species, Branchotenthes robinoverstreeti Bullard et Dippenaar, 2003, by producing eggs that are joined end to end forming a chain, in the morphology of the male copulatory organ that has a pronounced constriction in duct diameter between proximal and distal regions, the possession of a thin muscular layer surrounding the proximal part of the male copulatory organ and distal region of the vaginae, and by the absence of a raised process on the shaft of the hamulus. An amended generic diagnosis is provided and the reliability of sperm duct number as a generic character is discussed. The oncomiracidium of B. octohamatus is also described and is the first monogenean to be described with only eight hooklets in the larval haptor. This discovery of eight hooklets may be important for higher-level monogenean evolutionary hypotheses.