A new lecanicephalidean species of Aberrapex Jensen, 2001 is described from the blue-spotted fantail ray Taeniura lymma (Forsskål) collected off the eastern coast of Sabah in Malaysian Borneo. This is the first record of a lecanicephalidean tapeworm from the island of Borneo and the first record of Aberrapex from this host species. A. manjajiae n. sp. is easily distinguished from its two congeners, A. senticosus Jensen, 2001 and A. arrhynchum (Brooks, Mayes & Thorson, 1981) Jensen, 2001, based on its overall smaller size (928-1,971 vs 1,485-6,333 and up to 3,350 microm long, respectively) and fewer testes (10-19 vs 20-40 and 18-25, respectively). In addition, A. manjajiae n. sp. is readily distinguished from A. senticosus based on a more anteriorly positioned genital pore (76-85 vs 52-72% of proglottid length from posterior end) and its distal bothridial microthrix pattern. A. manjajiae n. sp. can be further distinguished from A. arrhynchum based on its smaller scolex (82-101 x 119-164 vs 177-186 x 233-326 microm). The host distribution of Aberrapex is expanded from the Myliobatidae to include the Dasyatidae.
A new genus of trypanorhynch cestode is described from two species of sharks, the sliteye shark Loxodon macrorhinus Müller & Henle and the straight-tooth weasel shark Paragaleus tengi (Chen) collected in the Makassar Strait (off Indonesian Borneo) and Sulu Sea (off Malaysian Borneo). Ancipirhynchus afossalis n. g., n. sp. possesses two bothria and a heteroacanthous, heteromorphous tentacular armature with three distinctive files of hooks on the external tentacle surface but lacks prebulbar organs and gland cells within the tentacular bulbs. The hook arrangement of alternating files on the external surface of the tentacle resembles that seen in the superfamily Otobothrioidea Dollfus, 1942 in the genus Fossobothrium Beveridge & Campbell, 2005. However, the new species lacks the defining characteristic of this group, i.e. the paired bothrial pits. A Bayesian inference (BI) analysis of 37 LSU sequences of trypanorhynchs from three superfamilies provided evidence supporting the taxonomic placement of Ancipirhynchus afossalis n. g., n. sp. within the Otobothrioidea.
The cestode fauna of the darkspotted numbfish, Narcine maculata (Shaw) (Torpediniformes: Narcinidae), from Malaysian Bomrneo was examined for the first time. This work resulted in the discovery of a new genus and two new species of Anteroporidae (Lecanicephalidea). Sesquipedalapex comicus gen. n., sp. n. was erected on the basis of the peculiarities of its scolex, in particular its possession of an extremely long apical modification of the scolex proper, which readily distinguishes it from the other genus in the family. The genus is also distinct in its possession of acetabula that are in the form of suckers, rather than bothridiate in form. This species was found to deeply embed its elongate apical structure for much of its length within the intestinal mucosa, provoking a papilliform expansion of the outer wall of the spiral intestine at the site of attachment. The second new species, Anteropora klosmamorphis sp. n., is readily distinguished from its congeners on the basis of testis number and bothridial shape. Both new species are hyperapolytic. The diagnosis of Anteroporidae is amended to accommodate both new taxa. This increases the total number of genera in the family to two, and the total number of species to five.
As part of a metazoan parasite survey of elasmobranchs from Malaysian Borneo, specimens of Rhoptrobothrium Shipley et Hornell, 1906 were collected from the eagle rays Aetomylaeus maculatus (Gray) and Aetomylaeus niehofii (Bloch et Schneider). The type species is redescribed from its type host, and a neotype specimen is designated. In addition, three new species of Rhoptrobothrium are described: R. chongi sp. n., R. gambangi sp. n. and R. limae sp. n. Rhoptrobothrium myliobatidis conspicuously differs from the three new species in its lack of a secondary areola; R. limae is distinguished from R. chongi and R. gambangi based on its greater total length; R. chongi possesses conspicuously stalked remi, while R. gambangi possesses short remi, often folded anteriorly. Rhoptrobothrium is somewhat unusual among tetraphyllideans in its possession of a "metascolex," a character it shares with other taxa in the Thysanocephalinae (i.e., Myzocephalus Shipley et Hornell, 1906, Myzophyllobothrium Shipley et Hornell, 1906 and Thysanocephalum Linton, 1889). The morphology of the "metascolex" of Rhoptrobothrium is investigated and new terminology is suggested to standardise the names given to structures constituting a metascolex. As a result, Rhoptrobothrium is considered to possess cephalic peduncle extensions, termed remi. In Rhoptrobothrium, each remus bears, at its distal end, a primary areola, and, in the case of the three new species, also a secondary areola proximal to the primary areola. Myzocephalus and Myzophyllobothrium are tentatively considered to possess remi; the configuration of the "metascolex" of Thysanocephalum, however, is not considered homologous to the condition in the other three genera currently placed in the Thysanocephalinae.
Lesions associated with two species of tapeworms within the digestive tract of wild-caught specimens of the bull shark, Carcharhinus leucas, and the sicklefin weasel shark, Hemigaleus microstoma, from Malaysian Borneo are described. Portions of the glandular stomach and pyloric gut with parasites were removed and fixed in 10% formalin buffered in sea water. Whole mounts, histological sections of tissues with and without worms in situ, and scanning electron microscopy images of detached worms were examined. Both species of cestodes belonged to the trypanorhynch family Tentaculariidae. Heteronybelinia estigmena was found in large numbers parasitizing the pyloric gut of C. leucas; an unidentified tentaculariid was found in relatively small numbers in both the glandular stomach and pyloric gut of H. microstoma. Both species burrowed their scoleces deeply in the mucosa and attached via hooked tentacles and unciniform microtriches of the scolex. The lesions induced by the parasites were marked in both sharks and ranged from acute necrotizing to chronic granulomatous gastroenteritis. Regenerative hyperplasia and intestinal metaplasia of gastric epithelium were also present. The severity and character of pathology was causally linked to the intensity of infection, the attachment mode of the parasites, and to the anatomophysiological relationships within the gut of the host shark.
The lecanicephalidean cestodes parasitizing the spiral intestine of the endangered giant freshwater whipray, Urogymnus polylepis (Bleeker), are investigated for the first time. Eight host specimens were collected between 2002 and 2008 at 2 collecting sites off the eastern coast of Borneo: 6 from the Kinabatangan River (Malaysia) and 2 from a fish market in Tarakan (Indonesia). Two of these individuals were found to be infected with a total of 3 new species of TetragonocephalumShipley and Hornell, 1905. Tetragonocephalum georgei n. sp. and Tetragonocephalum opimum n. sp. were recovered from a host specimen from the Kinabatangan River, and Tetragonocephalum levicorpum n. sp. was found parasitizing a host specimen purchased at a fish market in Tarakan. Specimens of each of the new species were prepared for light microscopy; specimens of 2 of the new species were prepared for scanning electron microscopy, and histological sections were prepared for 1 of the new species. The 3 new species are distinct from the 9 valid species of Tetragonocephalum and the 1 species inquirendum based on, for example, total length, number of proglottids and testes, and size of the scolex and acetabula. Tetragonocephalum georgei n. sp. and T. levicorpum n. sp. are unusual among their congeners in that they are euapolytic (i.e., gravid proglottids were not observed) rather than apolytic. They differ from one another in scolex and acetabula size. Tetragonocephalum opimum n. sp. is unusual among its congeners in its possession of vitelline follicles arranged in 2, rather than 3, regions in the proglottid. These new species increase the total number of valid species of Tetragonocephalum to 12 and the total number of known cestodes from U. polylepis to 13 species across 6 genera in 4 orders. This is the first account of lecanicephalideans reported from freshwater. The taxonomic status of each of the 32 nominal taxa historically associated with Tetragonocephalum is re-assessed. Type host identities of all valid species are revised and discussed in light of recent taxonomic efforts in the Dasyatidae Jordan and Gilbert.