Surface ultrastructure of the elasmobranchia parasitizing <Emphasis Type="Italic">Grillotiella exilis</Emphasis> and <Emphasis Type="Italic">Pseudonybelinia odontacantha</Emphasis> (Trypanorhyncha,Cestoda)

The surface ultrastructure of two monotypic trypanorhynch genera is described based on new material of Grillotiella exilis (Linton, 1909) and type material of Pseudonybelinia odontacantha Dollfus 1966. In G. exilis, spiniform microtriches cover the bothrial surfaces and the anterior part of the pars vaginalis posterior to the bothria. Bifurcate microtriches adorn the bothrial margins, filiform microtriches the scolex peduncle, and capilliform microtriches the posterior scolex end. This microthrix pattern resembles that found in, e.g., Grillotia erinaceus (van Beneden, 1858), with the difference that the anterior part of the pars vaginalis is covered with a collar of multidigitate palmate microtriches. The position of Grillotiella within the Grillotiinae, Lacistorhynchidae is supported based on these data. The bothria and scolex peduncle of P. odontacantha are covered with acerosate and unciniform microtriches on the distal bothrial surface and capilliform microtriches on the scolex peduncle. Short filiform microtriches cover the appendix. The microthrix pattern resembles that of the Tentaculariidae but with unciniform and acerosate microtriches densely covering the entire distal bothrial surface. Tegumental grooves are present on the posterior bothrial margin. They can be distinguished from bothrial pits in otobothrioid trypanorhynchs in having similar unciniform microtriches compared to the other parts of the bothrial surface and in lacking any spiniform microtriches. With the absence of bothrial pits as characteristic for the otobothrioids and its characteristic microthrix pattern, P. odontacantha together with Paranybelinia otobothrioides Dollfus 1966, both belonging to the Paranybeliniidae change their position in the most recent system from the Otobothrioidea into the Tentacularioidea.     

<Emphasis Type="Italic">Nataliella marcelli</Emphasis> n. g., n. sp. (Cestoda: Trypanorhyncha: Rhinoptericolidae) from Hawaiian fishes

A new trypanorhynch cestode from Hawaiian waters is described based on specimens in the collection of the Meguro Parasitological Museum, Tokyo, and newly collected specimens. Nataliella marcelli n. g., n. sp. is characterised by its elongate, craspedote scolex with four small, ear-shaped bothria, an elongate pars vaginalis and long bulbs. The homeoacanthous homeomorphous metabasal armature is comprised of five or six slender, solid hooks per half spiral row. A distinctive basal armature is present, including a combination of six characteristically shaped macrohooks not previously described for trypanorhynchs. The surface ultrastructure consists of gladiate spiniform microtriches that cover the distal and proximal bothrial surface and filiform microtriches on the scolex peduncle. The adults are not known. Nataliella is assigned to the family Rhinoptericolidae Carvajal & Campbell, 1975 based on its possession of four bothria, prebulbar organs and no chainette or intercalary hooks. The family diagnosis is amended to accommodate the new genus. Rhinoptericola megacantha Carvajal & Campbell, 1975 is considered the most closely related species, a position that has been confirmed by molecular analyses of the SSU and LSU rDNA. Nataliella n. g. is intermediate in morphology between the homeoacanth family Tentaculariidae Poche, 1926 (superfamily Tentacularioidea) and the Rhinoptericolidae and other eutetrarhynchid genera (superfamily Eutetrarhynchoidea), sharing characters of both superfamilies.     

Ultrastructure of the scolex of Orygmatobothrium schmittii (Cestoda: Phyllobothriidea)

The ultrastructure of the scolex of Orygmatobothrium schmittii (Cestoda: Phyllobothriidae) was studied using histochemistry, scanning, and transmission electron microscopy. The central bothridial structure resulted in a glandulomuscular organ formed by a mass of syncytial glands and radial muscles, with glycoprotein secretions potentially adhesive. Among the sensory receptors found on the scolex, a particular type was found surrounding the glandulomuscular organ, which might be related in the regulation of the secretions. The internal structure of the microtriches revealed a diversity of configurations according to their morphotype and distribution on the scolex. Microtriches with larger caps are thought to be useful for attachment purposes. In addition, the thick bounding membranes of the attachment organs and the circular musculature in the bothridia, seem to aid to the attachment of the scolex to the mucosa of the host.     

Poecilorhynchus perplexus n. g., n. sp. (Trypanorhyncha: Eutetrarhynchidae) from the brownbanded bambooshark, Chiloscyllium punctatum Müller & Henle, from Australia

A new genus of trypanorhynch cestodes is described from the brownbanded bambooshark, Chiloscyllium punctatum Müller & Henle (Hemiscylliidae) from off Nickol Bay, Western Australia. Poecilorhynchus perplexus n. g., n. sp. is placed in the Eutetrarhynchidae Guiart, 1927 because it is characterised by an elongate, acraspedote scolex with two oval bothria, the absence of bothrial pits, elongate bulbs, the presence of gland-cells within the bulbs and prebulbar organs, retractor muscles inserting at the base of each bulb and an acraspedote strobila. It can be distinguished from all other genera in this family by its possession of a poeciloacanthous typical armature, with a chainette composed of two longitudinal files of uncinate hooks on the external tentacular surface.     

A new genus and two new species of Aporhynchidae (Cestoda: Trypanorhyncha) from catsharks (Carcharhiniformes: Scyliorhinidae) off Taiwan

New collections of cestodes from the spiral intestines of catsharks (Carcharhiniformes: Scyliorhinidae) off Taiwan have led to the discovery of a new genus and 2 new species of trypanorhynchs. These taxa are relatively unique among trypanorhynchs in their lack of all elements of the rhyncheal apparatus. The new genus, Nakayacestus n. gen., is considered to belong with Aporhynchus in the Aporhynchidae. In addition to lacking the rhyncheal apparatus, these 2 genera share circum-medullary vitelline follicles, post-ovarian testes, and complex terminal genitalia consisting of accessory, external, and internal seminal vesicles. The 2 genera differ conspicuously in spinithrix configuration; whereas both species of Nakayacestus n. gen. bear scolex spinitriches that are bifid, trifid, or pectinate, species of Aporhynchus either lack scolex spinitriches entirely or possess spathulate spinitriches. The configuration of the bothria of the 2 genera also differ conspicuously. Whereas the bothria of Aporhynchus are sessile and generally do not extend beyond the lateral margins of the cephalic peduncle, those of Nakayacestus bear only a tenuous connection with the scolex proper, being conspicuously free both anteriorly and posteriorly and extending conspicuously beyond the cephalic peduncle. Futhermore, the boundary between the scolex and the strobila of members of the new genus is clearly delineated, whereas this distinction is ill-defined in species of Aporhynchus. Nakayacestus takahashii n. sp., the type of the new genus, was collected from the Broadmouth catshark, Apristurus macrostomus, and differs from Nakayacestus tanyderus n. sp., collected from the Blacktip sawtail catshark, Galeus sauteri, in being shorter, bearing a longer pedunculus scolecis, an ovary that is more posterior in the proglottid, and fewer post-ovarian testes. Furthermore, the 2 new species differ conspicuously from one another in the configuration of their scolex spinitriches.     

Ancipirhynchus afossalis n. g., n. sp. (Trypanorhyncha: Otobothriidae), from two species of sharks off Indonesian and Malaysian Borneo

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.     

Two new species of Echinobothrium (Cestoidea: Diphyllidea) from myliobatiform elasmobranchs in the Gulf of California, México

Two new species of diphyllidean cestodes, Echinobothrium mexicanum n. sp., and Echinobothrium fautleyae n. sp., are described, the former from the spiral intestines of the bat rays Myliobatis californicus and Myliobatis longirostris and the latter from the spiral intestine of the cownose ray Rhinoptera steindachneri, all caught in the Gulf of California, México. Echinobothrium mexicanum is most easily distinguished from the majority of the species of the genus by the number of large apical hooks in each dorsoventral group (23) and from the remainder in the number of lateral hooklets in each group on the scolex. Echinobothrium fautleyae differs conspicuously from all other members of the genus in that the first and last lateral hooklets in each group are distinctly larger than the other hooklets in each group. Serial sections of the scoleces of these 2 new species confirm that the attachment structures on the scolex are bothria, rather than bothridia, as has been described in other species in the genus, suggesting that the attachment structures of the scolex should be examined in more detail in the genus in general. Palmate microtriches of various forms cover the proximal bothrial surfaces of both new species and are also found on the dorsal bothrial surfaces of E. fautleyae. The distal bothrial surfaces of E. mexicanum are covered with slender spiniform and short filiform microtriches. The cephalic peduncles of both species possess short filiform microtriches only. Comparison of these 2 new species with the other 3 species in this genus that have been examined with SEM suggests that the various forms and distributions of these microtriches is unique in each of these 2 species. We believe these features will prove to be taxonomically useful.     

A new species of Ditrachybothridium (Cestoda: Diphyllidea) from Galeus sp. (Selachii, Scyliorhynidae) from the south Pacific Ocean, with a revision of the diagnosis of the order, family, and genus and notes on descriptive terminology of microtriches

Ditrachybothridium piliformis is a new species from the spiral intestine of a cat shark, Galeus sp., from the southern Pacific Ocean. This is only the second species assigned to Ditrachybothridium. It differs from the type species D. macrocephalum in lacking spines on the scolex, a character originally used to diagnose the genus. The diagnoses of the Ditrachybothridiidae and of Ditrachybothridium have been revised to reflect this difference. This new species is further differentiated from the type species in its possession of pectinate spinitriches on the tegument of the scolex. The holdfast structures of this species are weakly muscularized, with no membrane-bound layer of radial muscles, indicating that the holdfast structures are bothria rather than bothridia as described in the most recent literature. Several reports for other species have indicated the same situation in other diphyllideans. The diagnosis of the order has been revised to reflect this finding.     

An alternative classification of trypanorhynch cestodes considering the tentacular armature as being of limited importance

Based on a light- and scanning electron microscopical study of scolex morphology, tentacles and surface structures of 31 trypanorhynch species, an alternative classification of the trypanorhynch cestodes, adults, plerocerci and postlarvae, is presented. The arrangement of the tentacular armature is no longer used as a distinguishing feature for four different superfamilies. Instead, the presence or absence of ciliated pits and prebulbular organs is used to define three superfamilies: Tentacularioidea Poche, 1926; Otobothrioidea Dollfus, 1942; and Eutetrarhynchoidea Guiart, 1927. A total of 12 families are defined by the characters: the presence/absence of blastocysts, the number of bothridia and the reduction of the rhyncheal apparatus, together with a new character, complete rows of tentacular hooks (homeoacanth and heteroacanth typica) versus rows of hooks partly reduced (heteroacanth atypica and poeciloacanth). Of the 19 families previously accepted, 10 are retained (Eutetrarhynchidae, Gilquiniidae, Lacistorhynchidae, Mixodigmatidae, Otobothriidae, Paranybeliniidae, Pterobothriidae, Shirleyrhynchidae, Sphyriocephalidae and Tentaculariidae, all sensu nov.); one family is reinstated (i.e. Aporhynchidae Poche, 1926 sensu nov.) and a new one is added (i.e. Pseudotobothriidae n. fam.). Advantages of this alternative classification of trypanorhynch cestodes are: (i) the resolution of incongruities and questions caused by the use of the tentacular armature to distinguish superfamilies; (ii) the criteria for the establishment of higher taxa, superfamilies and families are clearly defined; (iii) with the findings of new species with different character combinations, this system can be enlarged up to 4 superfamilies and 48 families without loosing its stability; and (iv) all existing genera are easily re-assigned to the superfamilies and families.     

A revision of Microbothriorhynchus Yamaguti, 1952 (Cestoda: Trypanorhyncha), with the redescription of M coelorhynchi Yamaguti, 1952 and the description of M reimeri n sp

The genus Microbothriorhynchus Yamaguti, 1952 is revised. Plerocerci of M. coelorhynchi Yamaguti, 1952 from the body-cavity of Brotula barbata (Bloch & Schneider) off the Angolan coast are re-described, and M. reimeri n. sp. from the body-cavity of Helicolenus maculatus (Cuvier) and Caelorinchus parallelus (Günther) from coastal waters off Mozambique is added to the genus. Both species are characterised in having an elongated, slightly craspedote scolex with small, collar-like bothridia, an elongate pars vaginalis and very long bulbs. The tentacular armature is heteroacanthous atypica, with eight principal hooks and intercalary hooks merging with a band of spiniform hooks on the external tentacle surface. The adult is unknown. Microbothriorhynchus is allocated to the Lacistorhynchidae Guiart, 1927, in having a blastocyst, two bothridia and a heteroacanthous atypica armature. Dasyrhynchus Pintner, 1928 and Pseudogrillotia Dollfus, 1969 are considered the most closely related genera, sharing characters such as the craspedote scolex, similar scolex proportions and hook patterns. Microbothriorhynchus appears to link the heteroacanthous atypica genera Grillotia Guiart, 1927 and Pseudogrillotia with the poeciloacanthous genus Dasyrhynchus.     

Two new tapeworms from the goblin shark Mitsukurina owstoni off Australia

Internal parasites are reported from the goblin shark Mitsukurina owstoni for the first time. The shark examined was a 190 kg male collected off of Ulladulla, New South Wales, Australia and deposited at the Australian Museum in Sydney. What appear to be 4 different species of tapeworms were recovered from the spiral intestine. These included two new species, Litobothrium amsichensis n. sp. (order Litobothridea) and Marsupiobothrium gobelinus n. sp. (order Tetraphyllidea), as well as one specimen of a trypanorhynch and one scolex of a second tetraphyllidean. The latter two species are unidentifiable without further material. The generic placement of the new tetraphyllidean is somewhat problematical; this genus was thought to be the most appropriate placement at present. The most conspicuous difference between the new litobothridean and the five other species in the order is that it possesses dorso-ventral projections on five rather than four or three anterior segments. The discovery of a litobothridean parasitising the goblin shark is consistent with the systematic placement of the Mitsukurinidae within the Lamniformes, and may preliminarily indicate close affinities between the Alopidae, Odontaspidae and Mitsukurinidae. The phyllobothriid differs from the five other species of Marsupiobothrium in its possession of extremely long bothridial peduncles, its lack of an arcuate cylindrical pad on the posterior bothridial margins and its possession of a marginal, distinct apical sucker rather than a submarginal, diffuse apical sucker on each bothridium. Four detached specimens of the new phyllobothriid retained tips of mucosal villi within their bothridia. From these specimens it appears that the peduncles allow this species to stretch its scolex for attachment to up to four villi simultaneously.     

A new genus and species of the trypanorhynch family Otobothriidae Dollfus, 1942 from the slender weasel shark <Emphasis Type="Italic">Paragaleus randalli</Emphasis> Compagno,Krupp &amp; Carpenter (Hemigaleidae) in the Persian Gulf

A survey on the cestode fauna of Paragaleus randalli Compagno, Krupp & Carpenter in the Persian Gulf resulted in the discovery of a new trypanorhynch species of the family Otobothriidae Dollfus, 1942, the second otobothrioid species hosted by the family Hemigaleidae Hasse. The new species exhibits the closest morphological similarity to Pristiorhynchus palmi Schaeffner & Beveridge, 2013, the type- and only species of its genus. However, the new species differs from P. palmi in the position of the bothrial pits, the morphology and oncotaxy of the basal armature, the commencement of the hook files on the internal surface, a wider scolex peduncle in the pars bulbosa than in the pars vaginalis, a long neck and the presence of a lateral bothrial groove connecting the two bothrial pits to each other. The latter character is a unique trait within the Otobothrioidea Dollfus, 1942. Considering such differences, a new genus, Olgaella n. g., was erected to accommodate O. elenae n. g., n. sp. within the Otobothriidae. The evolutionary relatedness of the bothrial pits of the Otobothrioidea and the bothrial grooves of the Lacistorhynchoidea Guiart, 1927 is discussed.     

Microthrix pattern of Pseudogilquinia thomasi (Palm, 2000) (Cestoda: Trypanorhyncha) and a review of surface ultrastructure within the family Lacistorhynchidae Guiart, 1927

The microthrix pattern of larvae of Pseudogilquinia thomasi (Palm, 2000) is described for the first time using scanning electron microscopy. The surface ultrastructure of this species consists of three main forms of microtriches: papilliform filitriches, acicular filitriches and quadridigitate to octadigitate palmate spinitriches. The bothria are covered with palmate spinitriches interspersed on some parts with papilliform filitriches. Palmate spinitriches with papilliform, acicular and capilliform filitriches adorn the pars vaginalis and at the anterior part of the pars bulbosa, there is a transition zone in which the palmate spinitriches are replaced by papilliform to acicular filitriches towards the end of the scolex. ANOVA tests with Duncan's post hoc analyses revealed that there are significant differences in the length of spinitriches and their prongs, whether on the surfaces of the bothria or on the surfaces of the scolex peduncle. Callitetrarhynchus gracilis Pintner, 1931 is the second lacistorhynchid species for which surfaces of the segments were examined and the occurrence of large structures called scutes are reported for the first time from this species. There were also significant differences in the base length as well as height of the scutes in different parts of the strobila. In addition to describing the surface ultrastructures of the two lacistorhynchid species, all the available information on the microtriches within the family Lacistorhynchidae is reviewed herein and generic diagnoses related to microtriches are amended. J. Morphol. 277:394–404, 2016. © 2015 Wiley Periodicals, Inc.     

Two new species of Aporhynchus (Cestoda: Trypanorhyncha) from deep water lanternsharks (Squaliformes: Etmopteridae) in the Azores, Portugal

New collections of cestodes from the spiral intestines of the lanternsharks Etmopterus spinax and Etmopterus pusillus off the island of Faial, in the Azores, Atlantic Ocean, have yielded 2 new species of trypanorhynchs belonging to Aporhynchus. Both species share the distinctive lack of all elements of the rhyncheal system that are characteristic of this genus. The identity of Aporhynchus norvegicus is clarified to allow it to be distinguished from A. menezesi n. sp., which also parasitizes E. spinax. This new species differs conspicuously from its congeners in that its mature and gravid proglottids are wider than long, rather than longer than wide, and also in its lack of spinitriches on the scolex. Aporhynchus pickeringae n. sp., the new species from E. pusillus , differs from all of its congeners except A. norvegicus in that it is a relatively delicate worm with relatively fewer testes. It also possesses fewer proglottids and a wider pedunculus scolecis than does A. norvegicus. Sections through the scolex of A. menezesi n. sp. support use of the term bothriate, rather than difossate, in reference to the scolex configuration of some trypanorhynchs. A key to the 4 species of Aporhynchus is provided.     

Proemotobothrium n. g. (Cestoda: Trypanorhyncha), with the redescription of P. linstowi (Southwell, 1912) n. comb. and description of P. southwelli n. sp.

A new genus, Proemotobothrium (Trypanorhyncha: Otobothriidae), is erected to contain P. linstowi (Southwell, 1912) n. comb. (syn. Otobothrium magnum Southwell, 1924) and P. southwelli n. sp. The new genus is characterised by two bothridia, paired bothridial pits, an acraspedote scolex, elongate bulbs, four hooks per principal row, hooks 4 (4') being small and uncinate, a single, filiform, intercalary hook between each principal row and by the arrangement, in tandem, of the two or three extra hooks of the armature of the external surface of the tentacle, a pattern previously known only in the family Mixodigmatidae. The two species are distinguished from one another on the basis of measurements of the scolex and bulbs, the sizes of the hooks of the principal rows and by the number and size of the additional hooks in the linear arrays on the external surface of the tentacle.