RESUMO
In a parasitological survey of fishes from Moreton Bay (southeastern Queensland, Australia), 169 teleost fishes, representing 54 species from 28 families, were examined for larval cestodes. Of these 54 species, 36 were found to be infected by metacestodes. Metacestodes were characterised by morphological and molecular data (the D1-D3 region of the 28S rDNA gene); these data were analysed in parallel to inform larval type allocation. Metacestodes collected represented eight morphological types, seven previously reported (Types I, II, IV, V, VI, VII, and X) and one novel type (Type XVI). Phylogenetic analyses were conducted to genetically match larval types to adult cestodes. Six of the eight larval types found were matched to adult forms: Type I metacestodes matched species of Phoreiobothrium Linton, 1889 (Onchobothriidae); Type II metacestodes matched species of Acanthobothrium van Beneden, 1849 (Onchobothriidae); Type IV metacestodes matched species of Scyphophyllidium Woodland, 1927 and Alexandercestus Ruhnke & Workman, 2013 (Phyllobothriidae); Type VI metacestodes matched species of Anthobothrium van Beneden, 1850 (Tetraphyllidea incertae sedis); Type X metacestodes matched species of Ambitalveolus Caira & Jensen, 2022 (Tetraphyllidea incertae sedis); and Type XVI metacestodes matched species of Platybothrium Linton, 1890 (Onchobothriidae). Based on phylogenetic topology, Type V metacestodes are inferred to match Pedibothrium Linton, 1909 (Balanobothriidae) and Type VII metacestodes are inferred to match Spongiobothrium Linton, 1889 (Rhinebothriidae). These findings support and extend the unified morphological type system proposed previously, but suggest that morphological types will ultimately be informative to identify metacestodes to a group of related genera rather than any distinct genus.
Assuntos
Baías , Cestoides , Peixes , Filogenia , RNA Ribossômico 28S , Animais , Peixes/parasitologia , Cestoides/classificação , Cestoides/genética , Cestoides/anatomia & histologia , RNA Ribossômico 28S/genética , Queensland , Especificidade da Espécie , Larva/classificação , Larva/anatomia & histologia , DNA Ribossômico/genéticaRESUMO
We examined gelatinous zooplankton from off eastern Australia for lepocreadiid trematode metacercariae. From 221 specimens of 17 species of cnidarian medusae and 218 specimens of four species of ctenophores, infections were found in seven cnidarian and two ctenophore species. Metacercariae were distinguished using cox1 mtDNA, ITS2 rDNA and morphology. We identified three species of Prodistomum Linton, 1910 [P. keyam Bray & Cribb, 1996, P. orientale (Layman, 1930), and Prodistomum Type 3], two species of Opechona Looss, 1907 [O. kahawai Bray & Cribb, 2003 and O. cf. olssoni], and Cephalolepidapedon saba Yamaguti, 1970. Two species were found in cnidarians and ctenophores, three only in cnidarians, and one only in a ctenophore. Three Australian fishes were identified as definitive hosts; four species were collected from Scomber australasicus and one each from Arripis trutta and Monodactylus argenteus. Transmission of trematodes to these fishes by ingestion of gelatinous zooplankton is plausible given their mid-water feeding habits, although such predation is rarely reported. Combined morphological and molecular analyses of adult trematodes identified two cox1 types for C. saba, three cox1 types and species of Opechona, and six cox1 types and five species of Prodistomum of which only two are identified to species. All three genera are widely distributed geographically and have unresolved taxonomic issues. Levels of distinction between the recognised species varied dramatically for morphology, the three molecular markers, and host distribution. Phylogenetic analysis of 28S rDNA data extends previous findings that species of Opechona and Prodistomum do not form monophyletic clades.
Assuntos
Doenças dos Peixes , Trematódeos , Infecções por Trematódeos , Zooplâncton , Animais , Trematódeos/classificação , Trematódeos/genética , Trematódeos/isolamento & purificação , Trematódeos/anatomia & histologia , Infecções por Trematódeos/veterinária , Infecções por Trematódeos/parasitologia , Infecções por Trematódeos/epidemiologia , Austrália , Doenças dos Peixes/parasitologia , Doenças dos Peixes/epidemiologia , Japão , Cnidários/classificação , Peixes/parasitologia , Metacercárias/isolamento & purificação , Filogenia , DNA Espaçador Ribossômico/análise , DNA Mitocondrial/análise , DNA de Helmintos/análise , DNA Ribossômico/análise , População do Leste AsiáticoRESUMO
Geographical distribution plays a major role in our understanding of marine biodiversity. Some marine fish trematodes have been shown to have highly restricted geographical distributions, while some are known to occur over very wide ranges; however, very few of these wide distributions have been demonstrated genetically. Here, we analyse species of the genus Schikhobalotrema (Haplosplanchnidae) parasitizing beloniforms from the tropical west Pacific, the eastern Pacific and the Gulf of Mexico (GoM). We test the boundaries of these trematodes by integrating molecular and morphological data, host association, habitat of the hosts and geographical distribution, following a recently proposed and standardized delineation method for the recognition of marine trematode species. Based on the new collections, Schikhobalotrema huffmani is here synonymized with the type-species of the genus, Schikhobalotrema acutum; Sch. acutum is now considered to be widely distributed, from the GoM to the western Pacific. Additionally, we describe a new species, Schikhobalotrema minutum n. sp., from Strongylura notata and Strongylura marina (Belonidae) from La Carbonera coastal lagoon, northern Yucatán, GoM. We briefly discuss the role of host association and historical biogeography of the hosts as drivers of species diversification of Schikhobalotrema infecting beloniforms.
Assuntos
Beloniformes , Trematódeos , Animais , Golfo do México , Oceano Pacífico , Trematódeos/genética , BiodiversidadeRESUMO
Pleustonic organisms form an important part of pelagic ecosystems by contributing to pelagic trophic chains and supporting connectivity between oceanic habitats. This study systematically analysed the trematode community harboured by pleustonic molluscs and cnidarians from offshore Queensland, Australia. Four mollusc and three cnidarian species were collected from beaches of North Stradbroke Island, Queensland. Two mollusc species and all three cnidarians harboured large numbers of hemiuroid metacercariae (Trematoda: Hemiuroidea). Eight taxa from four hemiuroid families (Accacoeliidae, Didymozoidae, Hemiuridae and Sclerodistomidae) were distinguished via molecular sequencing. Four of those taxa were identified to species. All trematode taxa except one didymozoid were shared by two or more host species; five species occurred in both gastropods and cnidarians. It is hypothesised that the life-cycles of these hemiuroids are highly plastic, involving multiple opportunistic pathways of metacercarial transmission to the definitive hosts. Transmission and the use of pleuston by hemiuroids likely varies with sea surface use and ontogenetic trophic shifts of apex predators. The small number of trematode species found in pleuston is consistent with significant ecological specificity, and the inference that other pelagic trematodes use alternative pathways of transmission that do not involve pleustonic organisms. Such pathways may involve i) pelagic hosts exclusively; ii) benthic or demersal hosts exclusively, consumed by apex predators during their dives; or iii) both benthic and pelagic hosts in transmission chains dependent on vertical migrations of prey. The influence of the connectivity of open-ocean ecosystems on parasite transmission is identified as an area in critical need of research.
RESUMO
Derogenes varicus (Müller, 1784) is widely reported as a trematode with exceptionally low host specificity and a wide, bipolar distribution. However, several recent studies have suggested that D. varicus represents a species complex and based on molecular evidence, four genetic lineages (labeled as "DV1-4") have been designated within the D. varicus species complex. This possibility requires improved (ideally molecular) characterisation of specimens from the type-host (Salmo salar) and type-locality (off Denmark). During examination of trematode parasites of fish from Scandinavian and Arctic waters (Sweden and Norway), we found specimens of D. varicus in the stomach of Merlangius merlangus off the coast of Sweden, and in Gadus morhua off the coast of Sweden and Norway; we compared them to D. varicus from the type-host, the Atlantic salmon Salmo salar from Norway, to verify their conspecificity. Newly generated sequences (28S rDNA, ITS2 and cox1) of Scandinavian and Arctic specimens consistent with D. varicus all formed a single clade, DV1. 28S sequences of D. varicus from S. salar from Norway, i.e., close to the Danish type locality, clustered within the DV1 clade along with sequences of D. varicus from various hosts including Limanda limanda, G. morhua and Myoxocephalus scorpius from the White Sea and the Barents Sea (Russia), without any host-related structuring. We thus consider that the lineage DV1 represents D. varicus sensu stricto. Additionally, specimens from M. merlangus had a similar morphology and anatomy to those of D. varicus from L. limanda, G. morhua and M. scorpius from T. Odhner's collection, supporting the presence of a single species in the DV1 lineage designated herein as D. varicus sensu stricto. We redescribe D. varicus sensu stricto, add new morphological characters and provide morphometric data. We infer that D. varicus types DV2-4 all relate to separate species. We also revise type-specimens of Derogenes minor Looss, 1901 from the A. Looss collection in the Swedish Museum of Natural History and provide redescriptions of it and of the type-species of the genus, Derogenes ruber Lühe, 1900. In light of their morphological distinctiveness relative to D. varicus sensu stricto, we reinstate D. parvus Szidat, 1950 and D. fuhrmanni Mola, 1912.
Title: Caché dans le brouillard : caractérisation morphologique et moléculaire de Derogenes varicus sensu stricto (Trematoda, Derogenidae) de Suède et de Norvège, et redescription de deux espèces de Derogenes peu connues. Abstract: Derogenes varicus (Müller, 1784) est largement signalé comme un trématode avec une spécificité d'hôte exceptionnellement faible et une large distribution bipolaire. Cependant, plusieurs études récentes ont suggéré que D. varicus représente un complexe d'espèces. Cette possibilité nécessite une meilleure caractérisation (idéalement moléculaire) des spécimens de l'hôte-type (Salmo salar) et de la localité-type (au large du Danemark). Lors de l'examen des trématodes parasites des poissons des eaux scandinaves et arctiques (Suède et Norvège), nous avons trouvé des spécimens de D. varicus dans l'estomac de Merlangius merlangus au large de la Suède, et dans Gadus morhua au large de la Suède et de la Norvège ; nous les avons comparés à D. varicus de l'hôte-type, le saumon atlantique Salmo salar de Norvège, pour vérifier leur conspécificité. Les séquences nouvellement générées (ADNr 28S, ITS2 et cox1) de spécimens scandinaves compatibles avec D. varicus ont toutes formé un seul clade, DV1. Les séquences 28S de D. varicus de S. salar de Norvège, c'est-à-dire proches de la localité-type au Danemark, se regroupent dans le clade DV1 avec des séquences de D. varicus de divers hôtes dont Limanda limanda, G. morhua et Myoxocephalus scorpius de la mer Blanche et la mer de Barents (Russie), sans aucune structuration liée à l'hôte. Nous considérons donc que la lignée DV1 représente D. varicus sensu stricto. De plus, les spécimens de M. merlangus avaient une morphologie et une anatomie similaires à celles de D. varicus de L. limanda, G. morhua et M. scorpius de la collection de T. Odhner, confirmant la présence d'une seule espèce dans la lignée DV1 désignée ici comme D. varicus sensu stricto. Nous redécrivons D. varicus sensu stricto, ajoutons de nouveaux caractères morphologiques et fournissons des données morphométriques. Nous en déduisons que les types DV2-4 de D. varicus se rapportent tous à des espèces distinctes. Nous révisons également les spécimens-types de Derogenes minor Looss, 1901 de la collection d'A. Looss du Muséum Suédois d'Histoire Naturelle, et fournissons des redescriptions de cette espèce et de l'espèce-type du genre, Derogenes ruber Lühe, 1900. À la lumière de leur distinction morphologique par rapport à D. varicus sensu stricto, nous rétablissons D. parvus Szidat, 1950 et Derogenes fuhrmanni Mola, 1912.
Assuntos
Linguado , Animais , Suécia , Noruega , DNA Ribossômico , Especificidade de HospedeiroRESUMO
Species of Transversotrema Witenberg, 1944 (Transversotrematidae) occupy a unique ecological niche for the Trematoda, living externally under the scales of their teleost hosts. Previous studies of the genus have been impeded partly by limited variation in ribosomal DNA sequence data between closely related species and partly by a lack of morphometrically informative characters. Here, we assess richness of the tropical Indo-west Pacific species through parallel phylogenetic and morphometric analyses, generating cytochrome c oxidase subunit 1 mitochondrial sequence data and morphometric data for hologenophore specimens from Australia, French Polynesia, Japan and Palau. These analyses demonstrate that molecular data provide the only reliable basis for species identification; host distribution, and to a lesser extent morphology, are useful for identifying just a few species of Transversotrema. We infer that a combination of morphological simplicity and infection site constraint has led to the group displaying exceptionally low morphological diversification. Phylogenetic analyses of the mitochondrial data broadly support previous systematic interpretations based on ribosomal data, but also demonstrate the presence of several morphologically and ecologically cryptic species. Ten new species are described, eight from the Great Barrier Reef, Australia (Transversotrema chrysallis n. sp., Transversotrema daphnidis n. sp., Transversotrema enceladi n. sp., Transversotrema hyperionis n. sp., Transversotrema iapeti n. sp., Transversotrema rheae n. sp., Transversotrema tethyos n. sp., and Transversotrema titanis n. sp.) and two from off Japan (Transversotrema methones n. sp. and Transversotrema panos n. sp.). There are now 26 Transversotrema species known from Australian marine fishes, making it the richest trematode genus for the fauna.
Assuntos
Trematódeos , Animais , Filogenia , Austrália , Peixes , DNA Ribossômico/genéticaRESUMO
We report nine species of the Schistorchiinae Yamaguti, 1942 (Apocreadiidae Skrjabin, 1942) from Indo-Pacific marine fishes. Molecular data (ITS2 and 28S rDNA and cox1 mtDNA) are provided for all species and the genus-level classification of the subfamily is revised. For Schistorchis Lühe, 1906, we report the type-species Sch. carneus Lühe, 1906 and Sch. skrjabini Parukhin, 1963. For Sphinteristomum Oshmarin, Mamaev & Parukhin, 1961 we report the type-species, Sph. acollum Oshmarin, Mamaev & Parukhin, 1961. We report and re-recognise Lobatotrema Manter, 1963, for the type and only species, L. aniferum Manter, 1963, previously a synonym of Sph. acollum. Lobatotrema aniferum is phylogenetically distant from, but morphologically similar to, Sph. acollum and Lobatotrema is recognised as a 'cryptic genus'. We propose Blendiella n. gen. for B. trigintatestis n. sp. and B. tridecimtestis n. sp. These species are broadly consistent with the present morphological concept of Schistorchis but are phylogenetically distant from the type-species; a larger number of testes and some other subtle morphological characters in species of Blendiella serve to distinguish the two genera. We report three species of Paraschistorchis Blend, Karar & Dronen, 2017: P. stenosoma (Hanson, 1953) Blend, Karar & Dronen, 2017 (type-species), P. seychellesiensis (Toman, 1989) Blend, Karar & Dronen, 2017, and P. zancli (Hanson, 1953) Blend, Karar & Dronen, 2017. Lobatotrema aniferum, P. stenosoma, and Sch. carneus each have two distinct cox1 populations either over geographical range or in sympatry. Available evidence suggests that most of these species, but not all, are widespread in the tropical Indo-Pacific.
Assuntos
Peixes , Trematódeos , Animais , Filogenia , Especificidade da Espécie , Peixes/genética , DNA Ribossômico/genéticaRESUMO
Integration of morphological and molecular approaches to species delineation has become an essential part of digenean trematode taxonomy, particularly when delimiting cryptic species. Here, we use an integrated approach to distinguish and describe two morphologically cryptic species of Hysterolecitha Linton, 1910 (Trematoda: Lecithasteridae) from fishes of Moreton Bay, Queensland, Australia. Morphological analyses of Hysterolecitha specimens from six fish species demonstrated a complete overlap in morphometric data with no reliable differences in their gross morphological characters that suggested the presence of more than one species. Distinctions in ITS2 rDNA and cox1 mtDNA sequence data for corresponding specimens suggested the presence of two forms. A principal component analysis on an imputed dataset showed clear separation between the two forms. These two forms are partially separated on the basis of their host's identity. Therefore, we describe two morphologically cryptic species: Hysterolecitha melae n. sp. from three species of Abudefduf Forsskål and one species of Parma Günther (Pomacentridae), with the Bengal sergeant, Abudefduf bengalensis (Bloch), as the type-host; and Hysterolecitha phisoni n. sp. from species of Pomacentridae (including A. bengalensis), Pomatomidae and Siganidae, with the black rabbitfish, Siganus fuscescens (Houttuyn), as the type-host.
Assuntos
Doenças dos Peixes , Perciformes , Trematódeos , Infecções por Trematódeos , Animais , Baías , Especificidade de Hospedeiro , Filogenia , Especificidade da Espécie , Austrália , PeixesRESUMO
Neospirorchis Price, 1934 is a genus of blood flukes that infect the cardiovascular system, including vessels surrounding the nervous systems of marine turtles. Although the genus comprises just two named species, the available molecular data suggest substantial richness which has not yet been formally described. The lack of description of species of Neospirorchis is probably explained by their small, slender, elongate bodies, which allow them to infect numerous organs and vessels in their hosts, such as the heart and peripheral vessels of nervous system, endocrine organs, thymus, mesenteric vessels, and gastrointestinal submucosa. This morphology and site of infection means that collecting good quality, intact specimens is generally difficult, ultimately hampering the formal description of species. Here we supplement limited morphological samples with multi-locus genetic data to formally describe four new species of Neospirorchis infecting marine turtles from Queensland, Australia and Florida, USA; Neospirorchis goodmanorum n. sp. and Neospirorchis deburonae n. sp. are described from Chelonia mydas, Neospirorchis stacyi n. sp. is described from Caretta caretta, and Neospirorchis chapmanae n. sp. from Ch. mydas and Ca. caretta. The four new species are delineated from each other and the two known species based on the arrangement of the male and female reproductive organs, on the basis of cytochrome c oxidase subunit 1 (cox1), internal transcribed spacer 2 (ITS2), and 28S ribosomal DNA (rDNA) molecular data, site of infection, and host species. Molecular evidence for three further putative, presently undescribable, species is also reported. We propose that this integrated characterisation of species of Neospirorchis, based on careful consideration of host, molecular and key morphological data, offers a valuable solution to the slow rate of descriptions for this important genus. We provide the first known life cycle data for Neospirorchis in Australian waters, from Moreton Bay, Queensland; consistent with reports from the Atlantic, sporocysts were collected from a terebellid polychaete and genetically matched to an unnamed species of Neospirorchis infecting Ch. mydas from Queensland and Florida.
Assuntos
Trematódeos , Infecções por Trematódeos , Tartarugas , Animais , Feminino , Masculino , Austrália , Coração , DNA Ribossômico/genética , FilogeniaRESUMO
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.
Assuntos
Bivalves , Perciformes , Trematódeos , Animais , Trematódeos/genética , Filogenia , Nova CaledôniaRESUMO
The family Aporocotylidae is recognized as having the widest intermediate host usage in the Digenea. Currently, intermediate host groups are clearly correlated with definitive host groups; all known life cycles of marine teleost-infecting aporocotylids involve polychaetes, those of freshwater teleost-infecting aporocotylids involve gastropods, and those of chondrichthyan-infecting aporocotylids involve bivalves. Here we report the life cycle for a marine elopomorph-infecting species, Elopicola bristowi Orélis-Ribeiro & Bullard in Orélis-Ribeiro, Halanych, Dang, Bakenhaster, Arias & Bullard, 2017, as infecting a bivalve, Anadara trapezia (Deshayes) (Arcidae), as the intermediate host in Moreton Bay, Queensland, Australia. The cercaria of E. bristowi has a prominent finfold, distinct anterior and posterior widenings of the oesophagus, a tail with symmetrical furcae with finfolds, and develops in elongate to oval sporocysts. We also report molecular data for an unmatched aporocotylid cercaria from another bivalve, Megapitaria squalida (G. B. Sowerby I) (Veneridae), from the Gulf of California, Mexico, and six unmatched cercariae from a gastropod, Posticobia brazieri (E. A. Smith) (Tateidae), from freshwater systems of south-east Queensland, Australia. Phylogenetic analyses demonstrate the presence of six strongly-supported lineages within the Aporocotylidae, including one of elopomorph-infecting genera, Elopicola Bullard, 2014 and Paracardicoloides Martin, 1974, now shown to use both gastropods and bivalves as intermediate hosts. Of a likely 14 aporocotylid species reported from bivalves, six are now genetically characterised. The cercarial morphology of these six species demonstrates a clear distinction between those that infect chondrichthyans and those that infect elopomorphs; chondrichthyan-infecting aporocotylids have cercariae with asymmetrical furcae that lack finfolds and develop in spherical sporocysts whereas those of elopomorph-infecting aporocotylids have symmetrical furcae with finfolds and develop in elongate sporocysts. This morphological correlation allows predictions of the host-based lineage to which the unsequenced species belong. The Aporocotylidae is proving exceptional in is propensity for major switches in intermediate host use, with the most parsimonious interpretation of intermediate host distribution implying a minimum of three host switches within the family.
Assuntos
Bivalves , Gastrópodes , Esquistossomose , Trematódeos , Infecções por Trematódeos , Animais , Infecções por Trematódeos/veterinária , Filogenia , Estágios do Ciclo de Vida , OocistosRESUMO
Species of the digenean genus Enenterum Linton, 1910 (Lepocreadioidea: Enenteridae) are characterised primarily by their elaborate oral suckers, which are divided into varying numbers of anteriorly directed lobes, and their host-restriction to herbivorous marine fishes of the family Kyphosidae. We describe Enenterum petrae n. sp. from the brassy chub Kyphosus vaigiensis (Quoy Gaimard) collected off Lizard Island, Great Barrier Reef, Queensland, Australia. Enenterum petrae n. sp. is readily differentiated from congeners by its unique oral sucker morphology, in having a minute pharynx, and the combination of a genital cap and accessory sucker. We also provide the first record of Enenterum kyphosi Yamaguti, 1970 from Australia based on material obtained from the blue sea chub Kyphosus cinerascens (Forsskl) collected off Lizard Island and North Stradbroke Island, Queensland. Morphologically, our specimens of E. kyphosi agree closely with descriptions of this species from Hawaii and South Africa, and despite lack of molecular data from outside of Australian waters, we consider all three reports to represent a single, widespread species. The first ITS2 and COI mtDNA gene sequences for species of Enenterum are provided and molecular phylogenetic analyses of 28S rDNA gene sequences place these species in a strongly-supported clade with the type-species of the genus, Enenterum aureum Linton, 1910. The oral suckers of both E. kyphosi and E. petrae n. sp. can be interpreted as having varying numbers of lobes depending on the particular specimen and how the division between lobes is defined. Scanning electron microscopical images improves understanding of the morphology of the enenterid oral sucker, and permits speculation regarding the evolutionary history leading to its specialisation in this lineage.
Assuntos
Cifose , Lagartos , Perciformes , Trematódeos , Animais , Austrália , Peixes , Filogenia , Especificidade da EspécieRESUMO
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.
Assuntos
Gastrópodes , Perciformes , Trematódeos , Infecções por Trematódeos , Animais , Austrália , DNA Ribossômico/genética , Peixes/genética , Estágios do Ciclo de Vida , Filogenia , Especificidade da Espécie , Trematódeos/genéticaRESUMO
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.
RESUMO
The first first-intermediate host for a species of Didymozoidae (Trematoda: Hemiuroidea), a bivalve of the family Arcidae, is identified using multi-loci molecular data. First intermediate, (likely) third intermediate, and adult stages of a new didymozoid taxon (Saccularina magnacetabula n. gen. n. sp.) from Moreton Bay, Queensland, Australia were collected from the Sydney cockle Anadara trapezia (Deshayes) (Arcoidea: Arcidae), Sillago sp. (Sillaginidae) and Elops hawaiensis Regan (Elopiformes: Elopidae), respectively, and genetically matched. Infections in A. trapezia were present as sporocysts and cystophorous cercariae, and infected tissue at the base of the gills. Morphologically, S. magnacetabula is distinctive relative to all other didymozoids in the combination of hermaphroditism, mate-pairing, filiform body shape, the presence of a ventral sucker, a single testis, and a saccular excretory vesicle at the posterior extremity. Molecular sequence data were generated for S. magnacetabula and 42 other putative didymozoid species to explore relationships within the Didymozoidae and Hemiuroidea. In molecular phylogenetic analyses of the 28S rDNA region, the new genus forms a clade with an undescribed taxon from the redthroat emperor, Lethrinus miniatus (Bloch & Schneider) (Perciformes: Lethrinidae), from the Great Barrier Reef, and another uncharacterised taxon from E. hawaiensis. This clade is sister to a moderately well-supported clade comprising all other didymozoid species for which sequences are available, including representatives of five of the six presently recognised subfamilies. The infection of a bivalve by a didymozoid is discussed in the context of the overwhelming use of gastropod molluscs as first intermediate hosts by the Hemiuroidea.
Assuntos
Bivalves , Doenças dos Peixes , Perciformes , Trematódeos , Infecções por Trematódeos , Animais , Bivalves/genética , Peixes , Estágios do Ciclo de Vida , Masculino , Filogenia , RNA Ribossômico 28S/genéticaRESUMO
We report four new species of monorchiids infecting teleost fishes from Australian waters. Two new species of Paralasiotocus Wee, Cutmore, Pérez-del-Olmo & Cribb, 2020, Pa. abstrusus n. sp. and Pa. tectus n. sp., are described from haemulids of the Great Barrier Reef. The two species are morphologically cryptic and occur in sympatry but differ significantly in cox1 mtDNA and ITS2 rDNA sequence data. Paralasiotocus tectus n. sp. is found only in Plectorhinchus albovittatus (Rüppell) whereas Pa. abstrusus n. sp. infects Pl. albovittatus, Plectorhinchus flavomaculatus (Cuvier) and Plectorhinchus lineatus (Linnaeus). The two species differ from all known species of Paralasiotocus in the possession of a clear gap in the spines of the terminal organ. A new species is described from a mullid, Parupeneus spilurus (Bleeker), from off Heron Island and Moreton Bay. The new species is morphologically broadly consistent with the concept of Paralasiotocus in the possession of an unspined genital atrium, bipartite terminal organ, and lobed ovary. However, it possesses a highly lobed cirrus and is phylogenetically widely separated from the two species of Paralasiotocus characterized here, and thus we propose Lobucirruatus infloresco n. g., n. sp. Proctotrema prominens n. sp., is described from Pl. albovittatus. It is differentiated from all other species of Proctotrema in the combination of a prominent metraterm, slightly fusiform body, slightly funnel-shaped oral sucker, elongate cirrus-sac, unlobed ovary, and caeca that terminate in the post-testicular region.
Assuntos
Gastrópodes , Trematódeos , Animais , Austrália , Baías , Feminino , Peixes , Filogenia , Especificidade da EspécieRESUMO
We report specimens of monorchiids infecting Haemulidae from the waters off Japan and Australia; these specimens represent five species of Helicometroides Yamaguti, 1934, three of which are unambiguously new. Helicometroides murakamii n. sp. infects Diagramma pictum pictum from off Minabe, Japan; Helicometroides gabrieli n. sp. infects Plectorhinchus chrysotaenia from off Lizard Island, Australia; and Helicometroides wardae n. sp. infects Plectorhinchus flavomaculatus and Plectorhinchus multivittatus from off Heron Island, Australia. Helicometroides murakamii n. sp. and H. gabrieli n. sp. conform to the most recent diagnosis of Helicometroides in lacking a terminal organ, but H. wardae n. sp. possesses a terminal organ with distinct, robust spines; despite this morphological distinction, the three form a strongly-supported clade in phylogenetic analyses. We also report specimens morphologically consistent with Helicometroides longicollis Yamaguti, 1934, from D. pictum pictum from off Minabe, Japan, and Diagramma pictum labiosum on the Great Barrier Reef, Australia. Genetic analyses of ITS2 rDNA, 28S rDNA and cox1 mtDNA sequence data for the Japanese specimens reveal the presence of two distinct genotypes. Specimens of the two genotypes were discovered in mixed infections and are morphologically indistinguishable; neither genotype can be associated definitively with H. longicollis as originally described. We thus identify them as H. longicollis lineage 1 and 2, pending study of further fresh material. Genetic analyses of specimens from the Great Barrier Reef are consistent with the presence of only H. longicollis lineage 1. This species thus has a range that incorporates at least Australia and Japan, localities separated by over 7000 km.
RESUMO
Blood flukes of the family Spirorchiidae Stunkard, 1921 are significant pathogens of marine turtles, both in the wild and in captivity. Despite causing considerable disease and mortality, little is known about the life cycles of marine species, with just four reports globally. No complete life cycle has been elucidated for any named species of marine spirorchiid, but the group is reported to use vermetid and fissurellid gastropods, and terebelliform polychaetes as intermediate hosts. Here we report molecular evidence that nine related spirorchiid species infect vermetid gastropods as first intermediate hosts from four localities along the coast of Queensland, Australia. ITS2 rDNA and cox1 mtDNA sequence data generated from vermetid infections provides the first definitive identifications for the intermediate hosts for the four species of Hapalotrema Looss, 1899 and Learedius learedi Price, 1934. Additionally, we provide a new locality report for larval stages of Amphiorchis sp., and evidence of three additional unidentified spirorchiid species in Australian waters. Based on the wealth of infections from vermetids during this study, we conclude that the previous preliminary report of a fissurellid limpet as the intermediate host for L. learedi was likely mistaken. The nine species found infecting vermetids during this study form a strongly supported clade exclusive of species of the other two marine spirorchiid genera for which sequence data are available; Carettacola Manter & Larson, 1950 which falls sister to the vermetid-infecting clade + a small clade of freshwater spirorchiids, and Neospirorchis Price, 1934 which is distantly related to the vermetid-infecting clade. We provide further evidence that spirorchiid transmission can occur in closed system aquaria and show that spirorchiid transmission occurs at both an important turtle rookery (Heron Island, southern Great Barrier Reef, Australia) and foraging ground (Moreton Bay, Australia). We discuss the implications of our findings for the epidemiology of the disease, control in captivity, and the evolution of vermetid exploitation by the Spirorchiidae.
Assuntos
Gastrópodes , Trematódeos , Infecções por Trematódeos , Tartarugas , Animais , Austrália , Estágios do Ciclo de Vida , Filogenia , Trematódeos/genética , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/veterináriaRESUMO
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.
Assuntos
Doenças dos Peixes , Trematódeos , Infecções por Trematódeos , Animais , Doenças dos Peixes/epidemiologia , Peixes , Filogenia , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/veterináriaRESUMO
A new genus and three new species of blood flukes (Aporocotylidae) are described from squirrelfishes (Holocentridae) from the Great Barrier Reef. Holocentricola rufus n. gen., n. sp. is described from Sargocentron rubrum (Forsskål), from off Heron Island, southern Great Barrier Reef, and Lizard Island, northern Great Barrier Reef, Australia. Holocentricola exilis n. sp. and Holocentricola coronatus n. sp. are described from off Lizard Island, H. exilis from Neoniphon sammara (Forsskål) and H. coronatus from Sargocentron diadema (Lacepède). Species of the new genus are distinct from those of all other aporocotylid genera in having a retort-shaped cirrus-sac with a distinct thickening at a marginal male genital pore. The new genus is further distinct in the combination of a lanceolate body, X-shaped caeca, posterior caeca that are longer than anterior caeca, a single, post-caecal testis that is not deeply lobed, a post-caecal, post-testis ovary that is not distinctly bi-lobed, and a post-ovarian uterus. The three new species can be morphologically delineated based on the size and row structure of the marginal spines, as well by total length, oesophagus and caecal lengths, and the position of the male genital pore, testes and ovary relative to the posterior extremity. The three species of Holocentricola are genetically distinct from each other based on cox1 mtDNA and ITS2 rDNA data, and in phylogenetic analyses of 28S rDNA form a well-supported clade sister to species of Neoparacardicola Yamaguti, 1970. This is the first report of aporocotylids from fishes of the family Holocentridae and the order Holocentriformes.
TITLE: Un nouvel ordre de poissons comme hôtes de digènes du sang (Aporocotylidae) ; description d'un nouveau genre et de trois nouvelles espèces infectant les poissons-écureuils (Holocentriformes, Holocentridae) de la Grande Barrière de Corail. ABSTRACT: Un nouveau genre et trois nouvelles espèces de digènes du sang (Aporocotylidae) sont décrits de poissons-écureuils (Holocentridae) de la Grande Barrière de Corail. Holocentricola rufus n. gen., n. sp. est décrit de Sargocentron rubrum (Forsskål), de Heron Island, au sud de la Grande barrière de corail, et de Lizard Island, au nord de la Grande barrière de corail, en Australie. Holocentricola exilis n. sp. et Holocentricola coronatus n. sp. sont décrits de Lizard Island, H. exilis de Neoniphon sammara (Forsskål) et H. coronatus de Sargocentron diadema (Lacepède). Les espèces du nouveau genre se distinguent de celles de tous les autres genres d'Aporocotylidae en ce qu'elles ont un sac du cirre en forme de cornue avec un épaississement distinct au niveau d'un pore génital mâle marginal. Le nouveau genre se distingue en outre par la combinaison d'un corps lancéolé, de caeca en forme de X, de caeca postérieurs plus longs que les caeca antérieurs, d'un seul testicule post-caecal qui n'est pas profondément lobé, d'un ovaire post-caecal et post-testiculaire qui n'est pas distinctement bilobé, et d'un utérus post-ovarien. Les trois nouvelles espèces peuvent être délimitées morphologiquement en fonction de la taille et de la structure des rangées des épines marginales, ainsi que de la longueur totale, de la longueur de l'Åsophage et des caeca, et de la position du pore génital mâle, des testicules et de l'ovaire par rapport à l'extrémité postérieure. Les trois espèces d'Holocentricola sont génétiquement distinctes les unes des autres sur la base des données d'ADNr cox1 et d'ADNr ITS2, et forment un groupe-frère bien soutenu des espèces de Neoparacardicola Yamaguti, 1970 dans les analyses phylogénétiques de l'ADNr 28S. Il s'agit du premier signalement d'Aporocotylidae chez des poissons de la famille des Holocentridae et de l'ordre des Holocentriformes.