44 research outputs found

    Diversity and Phylogenetic Relationships of ‘Tetraphyllidean’ Clade 3 (Cestoda) Based on New Material from Orectolobiform Sharks in Australia and Taiwan

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    In an effort to expand knowledge of Clade 3—one of the ten clades that compose the non-monophyletic order ‘Tetraphyllidea’ all current members of which parasitise orectolobiform sharks—we targeted species of orectolobiform sharks that had not previously been examined for ‘tetraphyllidean’ cestodes. That work led to the discovery of three new species off Australia and Taiwan. Ambitalveolus gen. n. was erected to accommodate these species. Ambitalveolus costelloae gen. n. et sp. n., Ambitalveolus kempi sp. n., and Ambitalveolus penghuensis sp. n. differ from one another in scolex size, genital pore position, and number of marginal loculi, proglottids, and testes. Among ‘tetraphyllideans’, the new genus most closely resembles the two other genera in Clade 3. It differs from Carpobothrium Shipley et Hornell, 1906 in lacking anterior and posterior flap-like extensions of its bothridia; instead, its bothridia are essentially circular. It differs from Caulopatera Cutmore, Bennett et Cribb, 2010 in that its vitelline follicles are in two lateral bands, rather than circum-medullary, and in that its bothridia bear, rather than lack, conspicuous marginal loculi. A key to the three genera in Clade 3 is provided. A phylogenetic analysis including new sequence data for one of the three new species of Ambitalveolus gen. n., the only species of Caulopatera, and all four described species and one undescribed species of Carpobothrium supports previously hypothesised close affinities between Caulopatera and Carpobothrium, with the new genus as their sister group. This is the first report of ‘tetraphyllidean’ cestodes from the orectolobiform shark family Brachaeluridae Applegate. The association of the new species with orectolobiform sharks is consistent with those of the other members of Clade 3. However, whereas species of Carpobothrium and Caulopatera parasitise members of the hemiscylliid genus Chiloscyllium MĂŒller et Henle, species of Amitalveolus gen. n. parasitise members of the Brachaeluridae and Orectolobidae Gill

    Electron microscopy reveals novel external specialized organs housing bacteria in eagle ray tapeworms

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    Nutritionally-based mutualisms with bacteria are known to occur in a wide array of invertebrate phyla, although less commonly in the Platyhelminthes. Here we report what appears to be a novel example of this type of association in two geographically disparate and phylogenetically distant species of tapeworms of eagle rays—the lecanicephalidean Elicilacunosus dharmadii off the island of Borneo and the tetraphyllidean Caulobothrium multispelaeum off Senegal. Scanning and transmission electron microscopy revealed that the grooves and apertures on the outer surfaces of both tapeworms open into expansive cavities housing concentrations of bacteria. This led us to reject the original hypothesis that these structures, and their associated mucopolysaccharides, aid in attachment to the host mucosa. The cavities were found to be specialized in-foldings of the tapeworm body that were lined with particularly elongate filitriches. Given tapeworms lack a gut and employ filitriches to assist in nutrient absorption, enhanced nutrient uptake likely occurs in the cavities. Each tapeworm species appeared to host different bacterial monocultures; those in E. dharmadii were coccoid-like in form, while those in C. multispelaeum were bacillus-like. The presence of bacteria in a specialized structure of this nature suggests the structure is a symbiotic organ. Tapeworms are fully capable of obtaining their own nutrients, and thus the bacteria likely serve merely to supplement their diet. Given the bacteria were also extracellular, this structure is more consistent with a mycetome than a trophosome. To our knowledge, this is not only the first evidence of an external symbiotic organ of any type in a nutritionally-based mutualism, but also the first description of a mycetome in a group of invertebrates that lacks a digestive system. The factors that might account for the independent evolution of this unique association in these unrelated tapeworms are unclear—especially given that none of their closest relatives exhibit any evidence of the phenomenon

    Erection of a New Onchobothriid Genus (Cestoda: Tetraphyllidea) and the Description of Five New Species from Whaler Sharks (Carcharhinidae)

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    This is the publisher's version, also available from http://www.bioone.org.The onchobothriid Triloculatum n. gen. is erected to house species formerly considered members of Phoreiobothrium, but that bear 3, rather than 5 or more, bothridial subloculi. The species formerly known as Phoreiobothrium triloculatum is designated as its type. This species is redescribed based on 2 syntypes and on voucher material consistent with type material taken from the type host, Carcharhinus obscurus, from the type and 1 additional locality. Examination of the cestode fauna of a diversity of carcharhinid sharks resulted in the discovery of an additional 5 new tri-subloculate species belonging to the genus. These include: Triloculatum andersonorum n. sp. from Negaprion acutidens; Triloculatum bullardi n. sp. from Carcharhinus brevipinna; Triloculatum geeceearelensis n. sp. from Carcharhinus isodon; Triloculatum jodyi n. sp. from Carcharhinus acronotus; and Triloculatum oregontwoae n. sp. from Carcharhinus plumbeus. The new species differ from one another in the number of proglottids, scolex size, number of testes, number of lateral columns of vitelline follicles, and whether they possess craspedote or acraspedote proglottids. Histology and scanning electron microscopy suggest that the new genus differs further from Phoreiobothrium in that its species possess an anterior margin of the posterior loculus that is fused to the anterior loculus, rather than free. The diagnosis of Phoreiobothrium is emended to accommodate the removal of tri-subloculate species and the new information on the condition of the locular interface, and the symmetrical ovary and vitelline follicles arranged in 2 lateral bands; each band consisting of 2 to many columns of follicles. Existing host data indicate that the new genus is restricted to only a subset of the sharks parasitized by species of Phoreiobothrium. Results from the examination of a diversity of carcharhinid species suggest that species in the new genus may have an affinity for the larger, i.e., >200 cm in total length, species of Carcharhinus and Negaprion. One of the new Triloculatum species was found to attach in the crypts lying between the larger ridges found on the mucosal surface of the posterior inner region of the scroll-type spiral intestine of C. brevipinna

    Three New Genera and Six New Species of Lecanicephalideans (Cestoda) from Eagle Rays of the Genus Aetomylaeus (Myliobatiformes: Myliobatidae) from Northern Australia and Borneo

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    This is the publisher's version, also available electronically from http://www.bioone.org.New lecanicephalidean cestodes inhabiting the spiral intestine were investigated in 4 of the 6 known species of eagle rays of the genus Aetomylaeus Garman. Hosts examined consisted of 5 specimens of Aetomylaeus vespertilio from northern Australia, 5 of Aetomylaeus maculatus from Borneo, 10 of Aetomylaeus nichofii sensu stricto from Borneo, and 7 of Aetomylaeus cf. nichofii 2 from northern Australia. As a result of these new collections, 3 new genera and 6 new species of lecanicephalideans are formally described. Aetomylaeus vespertilio hosted the new genera and species Collicocephalus baggioi n. gen., n. sp. and Rexapex nanus n. gen., n. sp., as well as Aberrapex weipaensis n. sp. Aetomylaeus maculatus and A. nichofii sensu stricto hosted 3 new species of the novel genus Elicilacunosus, with the former eagle ray hosting Elicilacunosus sarawakensis n. sp. and the latter hosting both Elicilacunosus dharmadii n. sp. and Elicilacunosus fahmii n. sp. No new lecanicephalideans were described from A. cf. nichofii 2. Collicocephalus n. gen. is conspicuously unique among the genera of its order in possessing a large, retractable apical organ that, in cross-section, is transversely oblong, rather than round. Rexapex n. gen. is distinctive in its possession of an apical organ that bears 18 papilliform projections around its perimeter, and Elicilacunosus n. gen. is unlike any other known lecanicephalidean, or eucestode, in its possession of a region of musculo-glandular tissue along the midline of the dorsal and ventral surfaces of its proglottids, manifested externally as a tandem series of depressions. Among other features, A. weipaensis n. sp. differs from its congeners in its lack of post-ovarian vitelline follicles. All 6 new species were each restricted to a single species of Aetomylaeus. These records formally establish species of Aetomylaeus as hosts of lecanicephalideans. A summary of cestodes of myliobatid rays is presented

    Floriparicapitus, a new genus of lecanicephalidean tapeworm (Cestoda) from sawfishes (Pristidae) and guitarfishes (Rhinobatidae) in the Indo-West Pacific

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    Floriparicapitus n. gen. (Cestoda: Lecanicephalidea), with F. euzeti n. gen. n. sp. as its type, is erected to house 3 new tapeworm species and 2 known species that are transferred to the new genus, all parasitizing sawfishes and guitarfishes (order Rhinopristiformes) in Indo-Pacific waters. The new genus differs from the 20 valid lecanicephalidean genera in its possession of a large scolex bearing a laterally expanded apical organ in the form of a rugose sheet in combination with a cirrus conspicuously armed with spinitriches and 3 pairs of excretory vessels. It most closely resembles Lecanicephalum, but differs conspicuously in its possession of 3, rather than 1, pair of excretory vessels. Two new species are described from sawfishes: Floriparicapitus euzeti n. sp., from Pristis clavata and Floriparicapitus juliani n. sp. from Pristis microdon, both from Australia. Floriparicapitus plicatilis n. sp. is described from the guitarfish Glaucostegus typus in Australia and the guitarfish Glaucostegus thouin in Malaysian Borneo. Two species formerly assigned to Cephalobothrium are transferred to the new genus; Floriparicapitus variabilis (Southwell, 1911) n. comb. from the sawfish Anoxypristis cuspidata in Sri Lanka and Floriparicapitus rhinobatidis (Subhapradha, 1955) n. comb. from the guitarfish Glaucostegus granulatus in India. The species from guitarfish differ conspicuously from those parasitizing sawfish in their possession of only 4 (F. plicatilis n. sp.) or 5 (F. rhinobatidis n. comb.) testes per proglottid, versus 9 or more in the 3 sawfish-parasitizing species. The latter 3 species differ from one another in scolex width, acetabular size, number of proglottids, and cirrus sac size. As it stands, the new genus appears to be restricted to a subclade of the Rhinopristiformes consisting of the sawfishes and species of Glaucostegus

    Orders out of chaos – molecular phylogenetics reveals the complexity of shark and stingray tapeworm relationships

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    Novel molecular data are presented to resolve the long-standing issue of the non-monophyly of the elasmobranch-hosted tapeworm order Tetraphyllidea relative to the other acetabulate eucestode orders. Bayesian Inference analyses of various combinations of full ssrDNA, and full or partial lsrDNA (D1-D3), sequence data, which included 134 species representing 97 genera across the 15 eucestode orders, were conducted. New ssrDNA data were generated for 82 species, partial lsrDNA data for 53 species, and full lsrDNA data for 29 species. The monophyly of each of the elasmobranch-hosted orders Cathetocephalidea, Litobothriidea, Lecanicephalidea, and Rhinebothriidea was confirmed, as was the non-monophyly of the Tetraphyllidea. Two relatively stable groups of tetraphyllidean taxa emerged and are hereby designated as new orders. The Onchoproteocephalidea n. ord. is established to recognize the integrated nature of one undescribed and ten described genera of hook-bearing tetraphyllideans, previously of the family Onchobothriidae, with the members of the order Proteocephalidea. The Phyllobothriidea n. ord. is established for a subset of 12 non-hooked genera characterized by scoleces bearing four bothridia each with an anterior accessory sucker; most parasitise sharks and have been assigned to the Phyllobothriidae at one time or another. Tentative ordinal placements are suggested for 8 additional genera; placements for the remaining tetraphyllidean genera have not yet emerged. We propose these 17 genera remain in the “Tetraphyllidea”. Among these, particularly labile across analyses were Anthobothrium, Megalonchos, Carpobothrium, Calliobothrium, and Caulobothrium. The unique association of Chimaerocestus with holocephalans, rather than with elasmobranchs, appears to represent a host-switching event. Both of the non-elasmobranch hosted clades of acetabulate cestodes (i.e., Proteocephalidea and Cyclophyllidea and their kin) appear to have had their origins with elasmobranch cestodes. Across analyses, the sister group to the clade of “terrestrial” cestode orders was found to be an elasmobranch-hosted genus; as was the sister to the freshwater fish and tetrapod-hosted Proteocephalidea. Whilst further data are required to resolve outstanding nomenclatural and phylogenetic issues, the present analyses contribute significantly to an understanding of the evolutionary radiation of the entire Cestoda. Clearly, elasmobranch tapeworms comprise the backbone of cestode phylogeny

    A Revision of the North American Papillose Allocreadiidae (Digenea) with Independent Cladistic Analyses of Larval and Adult Forms

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    Adult specimens of all 19 North American species of papillose allocreadiids were examined. A description and figure is given for the adult of each species; details of the cirrus sacs are presented for most spesies for the first time. Descriptions were emended where necessary and judgments were made on synonymies. Scanning electron micrographs of the oral sucker of 10 species are presented as is a new key to the 19 species. A cladistic analysis was performed on the group based on adult characters. The analysis indicated that the group is monophyletic on the basis of the ventral papillae associated with the oral sucker, and the following genera were substantiated: Bunodera Railliet, 1896, Bunoderella Schell, 1964, Crepidostomum Braun, 1900, and Paracreptotrematina Amin and Meyer, 1982. All available literature on the larval forms is summarized. Miracidial development was monitored in 5 species; scanning electron micrographs are presented for cercariae of 5 species, and indicate that all species possess filiform protrusions around the oral aperture and papillae on the margin of the acetabulum. Independent cladistic analyses were atrempted for miracidial and cercarial data. No miracidial characters were appropriate for the analysis, but a cercarial tree is presented. This study represents the first attempt at generation of independent cladograms for separate life cycle stages at the species level. The cercarial tree was congruent but not identical to the cladogram generated from adult data. A consensus tree summarizing both cercarial and adult morphological data is presented. Based on the monophyly of the group, it is recommended that all 19 species be placed in a single subfamily, Bunoderinae

    A REVISION OF THE NORTH AMERICAN PAPILLOSE ALLOCREADIIDAE WITH INDEPENDENT CLADISTIC ANALYSES OF LARVAL AND ADULT FORMS

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    Adult material of all 20 North American species of papillose allocreadiids was examined. A description and figure is given for each species; details of the cirrus sacs are presented for most species for the first time. Descriptions are emended where necessary and judgments were made on synonymies. Scanning electron micrographs of the oral sucker of 11 species are presented as is a new key to the 20 species. A cladistic analysis was performed on the group based on adult characters. The analysis indicated that the group is monophyletic on the basis of ventral papillae, and the following genera were substantiated: Bunodera Railliet, 1896, Bunoderella Schell, 1964, Crepidostomum Braun, 1900, and Paracreptotrematina Amin and Meyer, 1982. All available literature on the larval forms is summarized. Fresh larval material was collected for 6 species. Miracidial development was monitored in 5 species; scanning electron micrographs of cercariae are presented and indicate that all species possess papillae on the margin of the acetabulum. The life cycle of Bunodera mediovitellata Tsimbaliuk and Roitman, 1966 is presented for the first time. Independent cladistic analyses were attempted for miracidial and cercarial data. No miracidial characters were appropriate for the analysis, but a cercarial tree is presented. This study represents the first attempt at generation of independent cladograms for separate life cycle stages at the species level. The cercarial tree was congruent, although not identical, to the cladogram generated from adult data. A consensus tree, summarizing both cercarial and adult morphological data, is presented. Based on the monophyly of the group, it is recommended that all 20 species be placed in a single subfamily, Bunoderinae

    Disculiceps Joyeux & Baer, 1935 (Cestoidea): proposed conservation

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    Volume: 44Start Page: 168End Page: 16

    Three new species of Acanthobothrium (Cestoda: Tetraphyllidea) from Ocellated Electric Ray, Diplobatis ommata, in the Gulf of California, Mexico.

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    Ficha diagnostica del holotipo de Acanthobothrium dollyae, especie descrita en este protologo
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