A new trypanorhynch cestode, Grillotia borealis sp. n., is described from the spiral intestines of softnose skates of the genus Bathyraja collected from subarctic waters of the North Pacific Ocean: B. parmifera (Bean) (type host), B. aleutica (Gilbert) and B. interrupta (Gill et Townsend) from the Bering Sea and B. minispinosa Ishiyama et Ishihara and B. smirnovi (Soldatov et Pavlenko) from the Sea of Okhotsk off Japan. The new species is distinguished from other species of Grillotia by possession of the following combination of characters: four hooks per principal row, hooks 4(4') distinctly separated from hooks 3(3') of principal row, principal rows separated by 13-15 intercalary hooks in 2-3 rows, hooks 2(2') and 3(3') change in form along their respective files, hooks 1(1') do not change in form along the file, a broad band of microhooks on the external tentacular face, intermediary hooks are lacking, absence of a special basal armature, origin of the retractor muscle near middle of the bulb, average scolex ratio of 1 : 3 : 2 : 0.1, and a hermaphroditic sac. Grillotia borealis consistently favoured the most anterior regions of the spiral intestine. Seventy-one per cent of 21 attached worms occupied the most anterior chamber of the spiral valve and 52 per cent were embedded in the anterior surface of the spiral valve whorls. Factors which may limit the distribution of G. borealis within the spiral intestine of its host are discussed. Statistically significant differences occur in the mucosal morphology of B. aleutica and B. parmifera for villus length, diameter, spatial arrangement and number per unit area along the antero-posterior axis of the spiral intestine.
Grillotia epinepheli sp.n. is described on the basis of plerocerci found in the body cavity and peritoneum of the teleost, Epinephelus guaza (L.) (Perciformes: Serranidae) caught off Sardinia, Italy. The species is distinguished from congeners by its tentacular armament, particularly in the basal armature. The metabasal region is armed with rows of 8-9 principal hooks beginning on the internal face; hooks 9 (9’), if present, much smaller than hooks 8 (8’) and similar to minute hooks on the external face. There are three intercalary rows consisting of 3, 2 and 4 hooks each. The external face is armed with a longitudinal band of minute hooks arranged in about 4 files. Basal armature well developed and composed of 7-8 rows of falciform and spiniform hooks.
Postlarvae of the cestode Hepatoxylon trichiuri (Holten, 1802) were found attached to the surface of viscera of Prionace glauca (Linnaeus, 1758) taken from Atlantic coastal waters off the south coast of Massachusetts, USA. Gross anatomy of the attachment site shows a quadripartite rim surrounding a deep pit with holes corresponding to the penetration site of each tentacle. Hyperplasia of the liver capsule into outgrowths at the attachment site conform to the attachment of the bothridia. The cu-boidal epithelium of the liver capsule became columnar forming papillary outgrowths, with a dense fibrotic reaction beneath the attachment site and infiltration by leukocytes and pigment containing granulocytic cells. Blood sinusoids beneath the attachment site are greatly enlarged. Postlarvae attached to the surface of the epigonal organs of three blue sharks were not accompanied by reactions. SEM examination of the scolex of H. trichiuri postlarvae revealed fused pairs of bothridia within infolded muscular lateral rims, porose tegument devoid of microtriches and a bilateral plane of symmetry in the tentacular armature.
Examination of the type material of Progrillotia dollfusi Carvajal et Rego, 1983, and of new specimens recently collected off the coast of Argentina (including plerocerci from 10 species of teleosts and adults from Squatina guggenheim Marini), allowed a detailed redescription of this species and the evaluation of its current taxonomic status. The following characters that have been treated inconsistently by different authors have been herein corrected or confirmed: band of hooklets on external surface restricted to the base of the tentacle, external surface of metabasal region with 3-5 intercalary hooks arranged in a single row merging immediately to a cluster of 3-4 hooklets arranged in two rows; retractor muscle originating in the posterior third of the bulb, hollow hooks, and posterior margin of bothria notched. These features along with the presence of postovarian testes in the adults clearly confirm the placement of P. dollfusi in the genus Grillotia Guiart, 1927. In order to avoid the homonymy with Grillotia dollfusi Carvajal, 1971, a new name, Grillotia carvajalregorum nom. n., is proposed. This species differs from the 16 valid species in the genus in the combination of the following characters: number and morphology of hooks in principal rows in proximal metabasal region of the tentacle, number and distribution of intercalary hooks, presence of clusters of hooklets, extent of band of hooklets on external surface of basal armature, site of origin of the retractor muscle, and features of the terminal genitalia. The present study describes the plerocerci and adult worms, and provides detailed description of the microthrix pattern and histology of this species for the first time.
A new species of Nybelinia Poche, 1926, N. queenslandensis sp. n. (Cestoda: Trypanorhyncha) is described from sharks, Carcharhinus melanopterus (Quoy et Gaimard, 1824) from the coast of northeastern Queensland, Australia. Morphological features of the 46 known species of Nybelinia Poche, 1926 are tabulated and the new species is differentiated from all known taxa that are adequately described on the basis of having a homcomorphous armature, metabasal hooks 20-25 pm long, tentacles 0.07-0.09 mm in diameter, short bulbs (0.38-0.45 mm) and craspedote segments with the testes encircling the female genital complex. The fine structure of the scolex microtriches, frontal and rhynchodeal glands, tentacles and hooks, sheath and retractor muscle is described and compared with that of other trypanorhynchs.
Specimens of the elasmobranch, Isurus oxyrinchus Rafinesque, captured in 1999 in the state of Santa Catarina, Brazil, were parasitized with the poecilacanthoid trypanorhynch cestode Gymnorhynchus isuri Robinson, 1959, that is redescribed here. New details of scolex and proglottid morphology are given. These details are mainly related to tentacle armature, terminal genitalia and observations of external morphology of proglottids.
Progrillotia pastinacae Dollfus, 1946 (Cestoda: Trypanorhyncha) is redescribed from the spiral valve of Dasyatis pastinaca (Linnaeus) (Dasyatididae) from the coast of France. Progrillotia dasyatidis sp. n. is described from the spiral valves of Dasyatis tortonesei Capapé (Dasyatididae) from the Mediterranean in the Gulf of Gabès (Tunisia) and D. pastinaca from the Bassin d'Arcachon (France). The new species differs from congeners in having, on the tentacles, a single rather than two rows of intercalary hooks and fewer testes. The generic definition is emended based upon the new species, the redescription of P. pastinacae Dollfus, 1946 and re-examination of the type specimen of P. louiseuzeti Dollfus, 1969. Important additional characters noted are that the tentacular hooks are solid, a prebulbar organ is present and that there are gland cells attached to the retractor muscle within the bulb. A cladistic analysis suggests that the genus is closely allied with the Eutetrarhynchidae. Progrillotia dollfusi Carvajal et Rego, 1983 is provisionally excluded from the genus as the adult of the species is unknown and a key character of the genus is that the testes are pre-ovarian.
The family Rhopalothylacidae (Cestoda: Trypanorhyncha) is reviewed. The type species, Rhopalothylax gymnorhynchoides Guiart, 1935, is redescribed from the type specimens and belongs within the genus Pintneriella Yamaguti, 1934, previously described only from the plerocercus. Rhopalothylax therefore becomes a junior synonym of Pintneriella. The adult of Pintneriella musculicola Yamaguti, 1934 is described for the first time, from the shark Carcharias taurus Rafinesque from Australia. Pintneriella is characterised by two bothridia, a typical heteroacanthous armature, a unique, bipartite external seminal vesicle and a uterus deviated porally, terminating at a uterine pore. It belongs within the Heteracanthoidea but is distinguishable both from the Eutetrarhynchidae and the Gilquiniidae, the two families which it most closely resembles. Cladistic analyses align Pintneriella within the clade containing the families Gilquiniidae, Gymnorhynchidae and Molicolidae rather than with the Eutetrarhynchidae. The family Rhopalothylacidae is therefore retained provisionally to accommodate Pintneriella within the Heteracanthoidea. The second genus of the Rhopalothylacidae, Clujia Guiart, 1935, is unrecognisable from its description and cannot be redescribed from its holotype. It is therefore considered a genus inquirendum.
Spermiogenesis and the ultrastructural organisation of the spermatozoon of the trypanorhynch cestode Aporhynchus menezesi Noever, Caira, Kuchta et Desjardins, 2010 are described by means of transmission electron microscopy. Type I spermiogenesis of A. menezesi starts with the formation of a differentiation zone containing two centrioles separated by an intercentriolar body constituted by five electron-dense plates. Each centriole gives rise to a free flagellum, which grows at an angle of 90° in relation to a median cytoplasmic process. The nucleus and cortical microtubules elongate along the spermatid body. Later, both flagella rotate and fuse with the median cytoplasmic process. At the final stage of spermiogenesis, the young spermatozoon is detached from the residual cytoplasm by a narrowing of the ring of arched membranes. The mature spermatozoon is a long and filiform cell, tapered at both ends, lacking mitochondria. It is characterized by the presence of two axonemes of the 9+'1' trepaxonematan pattern, the absence of crested bodies, the presence of parallel cortical microtubules and nucleus. This pattern corresponds to the type I spermatozoon of the eucestodes. The anterior extremity of the spermatozoon is characterized by the presence of an arc-like row of up to seven parallel cortical microtubules that partially surrounds the first axoneme. These anterior cortical microtubules are thicker than the posterior microtubules and, consequently, the sperm cell of A. menezesi exhibits two types of cortical microtubules. Another interesting aspect is the presence of α-glycogen rosettes. This spermatological pattern is similar to that observed in the spathebothriidean and diphyllobothriidean cestodes.
Three new genera of eutetrarhynchid trypanorhynch cestodes are described from Mobula spp. (Mobulidae) from the Gulf of California, Mexico. Fellicocestus mobulae gen. et sp. n. from the gall bladder of Mobula japonica (Müller et Henle) is distinguished by elongate bothria, a pars bothrialis equal in length to the pars vaginalis, masses of gland cells in the pars vaginalis and an heteromorphous armature in which hook rows arise from a central file of hooks on the bothrial surface of the tentacle and terminate in a central file on the antibothrial surface. Species of Mobulocestus gen. n. occur in the nephridial system and cloaca of rays and are characterized by two bothria, an heteroacanthous armature with hook rows beginning on the bothrial surface and terminating on the antibothrial surface, and by hooks at the beginnings of rows with an apical cavity. M. nephritidis sp. n. and M. lepidoscolex sp. n., both from the nephridial system of Mobula thurstoni (Lloyd) are differentiated by testis number and by the presence of scale-like microtriches on the tegument of the scolex of M. lepidoscolex. M. mollis sp. n., from the cloaca of Mobula thurstoni is distinguished by testis number (97-111 in M. lepidoscolex, 20-22 in M. nephriticus and 48-70 in M. mollis). Hemionchos gen. n. from the spiral valve of Mobula spp. has two bothria, an heteroacanthous armature, hook rows arising on the bothrial surface and terminating on the antibothrial surface and hooks at the beginning of rows with an apical cavity. It differs from Mobulocestus in having a distinctive basal armature and both hook files 1 and 1' on the bothrial surface, but has an additional, small, satellite hook adjacent to each hook 1'. H. striatus sp. n. from the spiral valve of Mobula thurstoni and M. japonica is differentiated by having a basal armature of closely packed arrays of small, uncinate hooks. H. mobulae sp. n. from the spiral valve of Mobula japonica and M. munkiana Notarbartolo di Sciari, differs in testis number and in having large, flattened hooks in the basal armature. H. maior sp. n., from the spiral valve of M. japonica, is larger, differing in both the number of testes and in the basal armature.