Number Of Proglottids Research Articles

A New Species of Tetraphyllidean (Cestoda) from the Largespot River Stingray, Potamotrygon falkneri (Potamotrygonidae: Chondrichthyes), from the Paraná Basin

Rhinebothrium paranaensis n. sp. (Tetraphyllidea: Cestoda) is described from the freshwater stingray Potamotrygon falkneri collected in the Colastiné River, a tributary to the Lower Parana River in Argentina. The specimens were studied in detail using light and scanning electron microscopy and histology. Rhinebothrium paranaensis can be distinguished from all valid species in the genus using the following combination of characters: worm length, number of proglottids, diamond-shaped bothridia lacking constriction, number of loculi on the distal surface of bothridium, and the lack of vaginal sphincter and external seminal vesicle.

Five new species of Acanthobothrium (Cestoda: Tetraphyllidea) from an unusual species of Himantura (Rajiformes: Dasyatidae) from northern Australia

Five new species of Acanthobothrium van Beneden, 1850 from the spiral intestine of a specimen of an unusual species of Himantura from the Arafura Sea off northern Australia are described. Acanthobothrium oceanharvestae sp. n. is one of 26 category 1 species (sensu Ghoshroy and Caira 2001) lacking post-ovarian testes; it differs from these in total length, number of proglottids, number of testes, cirrus sac size and details of the terminal genitalia. Acanthobothrium popi sp. n. is unique among category 2 species in its possession of post-ovarian testes. Acanthobothrium rodmani sp. n. is a category 6 species distinct from all congeners in the dense blade-like spinitriches on the distal surfaces of its anterior-most bothridial loculi and conspicuously tapered posterior bothridial margins, which are reflexed anteriorly. Acanthobothrium romanowi sp. n. differs from most other category 1 species in that its genital pore is distinctly posterior. It differs from the remaining category 1 species in size, testis number, cephalic peduncle microthrix form, proglottid shape, and bothridial loculus dimensions. Acanthobothrium zimmeri sp. n. is among the six category 1 species with post-ovarian testes. It differs from these species in total length, ovary shape, number of proglottids and testes and vas deferens extent. This brings the number of Acanthobothrium species with post-ovarian testes to 10, all of which are Indo-Pacific in distribution, and 7 of which parasitize Himantura species. A key to the five new species parasitizing Himantura sp. is provided. Sequence data for the D1-D3 region of 28S rDNA for the five new species and two congeners parasitizing other Himantura species shows no intraspecific variation. Analysis of these and comparable data for two species available in GenBank (Acanthobothrium parviuncinatum and Acanthobothrium sp. 1) showed an interspecific variation of 0.7-11.3% among species pairs. Bayesian, Likelihood and Parsimony phylogenetic analyses of these data for these nine species indicate that the five new species parasitizing Himantura sp. are generally not each others' closest relatives.

A New Anoplocephalid (Cestoda: Cyclophyllidea) from Gallotia atlantica (Reptilia, Lacertidae) in the Canary Islands, Spain

A new species of anoplocephalid cestode is described from Gallotia atlantica (Reptilia, Lacertidae) on the Canary Islands, Spain. Oochoristica feliui n. sp. belongs to the group of Oochoristica spp. having circular suckers and fewer than 25 testes in a single cluster: O. lygosomae Burt, 1933; O. lygosomatis Skinker, 1935; O. elongata Dupouy et Kechemir, 1973; O. jonnesi Bursey, McAllister and Freed, 1997; O. junkea Johri, 1950; O. macallisteri Bursey and Goldberg, 1996; O. novaezelandae Schmidt and Allison, 1985; O. parvogenitalis Dupouy and Kechemir, 1973; and O. sobolevi (Spasskii, 1948) Spaskii, 1951. Oochoristica feliui n. sp. differs from these species in a variety of characters such as the number of proglottids, size of the scolex and suckers, presence of a neck, size and shape of the ovary (divided into 5-6 lobules), ovoid shape of the vitelline gland, a spined cirrus, size of eggs, oncosphere and oncosphere hooks, and the presence of 2 osmoregulatory canals. Gallotia spp. are endemic to the Canary Islands. This is the first report of an adult cestode species in this lizard.

Two new species of Anthobothrium van Beneden, 1850 (Tetraphyllidea: Phyllobothriidae) from carcharhinid sharks, with a redescription of Anthobothrium laciniatum Linton, 1890

Anthobothrium laciniatum Linton, 1890 is redescribed based on specimens taken from the dusky shark Carcharhinus obscurus (Lesueur) collected from the Northwestern Atlantic Ocean, and a neotype is designated. A. laciniatum differs from A. cornucopia van Beneden, 1850, A. altavelae Euzet & Ben Hassine, 2002, A. lesteri Williams, Burt & Caira, 2004 and A. spinosum Subhapradha, 1955 in total length. It further differs from A. cornucopia, A. altavelae and A. spinosum in proglottid number, and differs from A. galeorhini Suriano, 2002, A. cornucopia, and A. spinosum in testis number. A. lyndoni n. sp. is described from the sandbar shark C. plumbeus (Nardo). This new species differs from A. laciniatum in ovarian width and from A. cornucopia, A. altavelae, A. galeorhini and A. spinosum in the total number of proglottids. It further differs from A. cornucopia, A. galeorhini, and A. spinosum in total length, and from A. cornucopia and A. galeorhini in the number of testes. A. lyndoni n. sp. differs from A. lesteri in bothridial muscle and ovarian morphology. Anthobothrium caseyi n. sp. is described from Prionace glauca (Linnaeus). This new species differs conspicuously from the other six species of Anthobothrium van Beneden, 1850 (sensu stricto) in the shape of its proglottid laciniations. The taxonomic status of 43 species that have been associated with Anthobothrium is addressed. Taxonomic actions regarding Anthobothrium during the past century have resulted in a polyphyletic taxon.

Three new species of Anthocephalum Linton, 1890 (Cestoda: Tetraphyllidea) from dasyatid stingrays of the Gulf of California

Three new species of Anthocephalum Linton, 1890 are described from dasyatid stingrays collected in the Gulf of California. Anthocephalum michaeli n. sp. is described from Dasyatis longus (Garman). This species most closely resembles A. alicae Ruhnke, 1994, but differs from this species in proglottid number. A. lukei n. sp. is also described from D. longus. This new species is most similar to A. cairae Ruhnke, 1994, but differs from that species in marginal loculi number and number of proglottids. The third new species, A. currani n. sp., is described from D. brevis (Garman). This species is most similar to A. centrurum (Southwell, 1925) Ruhnke, 1994, but differs from that species in marginal loculi number, number of testes and ovarian length. Phyllobothrium kingae Schmidt, 1978 is also consistent in morphology with species of Anthocephalum and is transferred to this genus, forming the new combination Anthocephalum kingae n. comb. This species most closely resembles A. michaeli n. sp., but differs in testicular shape. This brings the total number of species of Anthocephalum to nine. The transfer of the species Phyllobothrium arctowskii Wojciechowska, 1991, P. georgiense Wojciechowska, 1991, P. rakusai Wojciechowska, 1991 and P. siedleckii Wojciechowska, 1991 to Anthocephalum is not warranted, as these four species lack a posteriorly recurved cirrus-sac and a sinuous vagina, and have vitelline follicles uninterrupted by the ovary. Of the nine known species, all are parasitic in batoid fishes, and six are found in species of Dasyatis Garman. The phylogenetic status of Anthocephalum species in relationship to Rhinebothroides Mayes, Brooks & Thorson, 1981, Pararhineothroides Zamparo, Brooks & Barriga, 1999 and other rhinebothriin taxa is discussed.

Orygmatobothrium Spp. (Cestoda: Tetraphyllidea) from Triakid Sharks in Argentina: Redescription of Orygmatobothrium schmittii and Description of a New Species

Two species of Orygmatobothrium were found inhabiting triakid sharks collected from the coast of Buenos Aires Province, Argentina. Orygmatobothrium schmittii from Mustelus schmitti is redescribed, including new information on the microtrich pattern. Orygmatobothrium juani n. sp. from Mustelus fasciatus can be distinguished from all other species in the genus using the following combination of characters: worm length, number of proglottids, number of testes, testes distribution, size of eggs, ornamented egg shell, shape of bothridial cleft at level of the marginal accessory sucker, and the extension of vitelline follicles. Species in Orygmatobothrium share a common microtrich pattern with the distal bothridial surface covered with maisiform microtriches interspersed with filiform microtriches, a proximal bothridial surface covered with trifid microtriches, with a medial projection conspicuously larger than the lateral basal projections interspersed with filiform microtriches, an inner and outer surface of the accessory sucker and glandulomuscular organ covered with short filiform microtriches, the scolex proper and cephalic peduncle surface covered with bladelike microtriches, and the germinative zone and entire strobila covered with scutes formed by densely packed filiform microtriches. This general configuration is basically similar to the microtrich pattern described in species of Orectolobicestus and Paraorygmatobothrium.

Taxonomic revision and phylogenetic analysis of the cestode genus Paraprogynotaenia Rysavy, 1966 (Cyclophyllidea: Progynotaeniidae)

The type-series of Paraprogynotaenia jimenezi Rysavy, 1966 [type-species of Paraprogynotaenia Rysavy, 1966] from Charadrius wilsonia Ord in Cuba and P. charadrii (Yamaguti, 1956) (= Proterogynotaenia charadrii Yamaguti, 1956) from C. alexandrinus L. in Japan are redescribed. Two new species are described: Paraprogynotaenia minuta n. sp. from C. alexandrinus on the Black Sea coast of Bulgaria [type-host and type-locality, based on specimens previously reported as P. charadrii], from the same host species in Tunisia and from "Tringa totanus" (the host identification is uncertain) in France [the latter two samples were previously reported as Progynotaenia odhneri Nybelin, 1916]; and Paraprogynotaenia canarisi n. sp. from C. marginatus Vieillot in the Republic of South Africa [type-host and type-locality] and from C. alexandrinus and Pluvialis dominica (Müller) in Taiwan [specimens from both localities were previously reported as Paraprogynotaenia charadrii]. P. jimenezi can be distinguished from its congeners by having 12 hooks of equal length. Among the remaining species with 18-22 hooks of varying length, P. minuta n. sp. can be distinguished by the smaller number of proglottides: up to 8 vs 15-20 for P. charadrii and P. canarisi n. sp. The latter two species can be differentiated from one another by the blade length/total length ratio of the smallest (lateral) rostellar hooks, which is less than 0.5 for P. canarisi n. sp. and 0.5 or more for P. charadrii. An identification key to the species of Paraprogynotaenia is provided and the generic diagnosis is amended. A phylogenetic analysis based on 17 morphological characters resulted in the following hypothesis for the relationships within the genus: (P. jimenezi (P. minuta (P. charadrii, P. canarisi))).

Calliobothrium schneiderae n. sp. (Cestoda: Tetraphyllidea) from the Spotted Estuary Smooth-Hound Shark, Mustelus lenticulatus, from New Zealand

New collections of tapeworms from the spiral intestine of the spotted estuary smooth-hound shark, Mustelus lenticulatus, in New Zealand led to the discovery of a species that appeared to be conspecific with specimens identified by Alexander (1963) as Calliobothrium eschrichti. Study of these newly collected specimens and some of Alexander's voucher material indicated that the species is new to science. Of the 15 described species in this genus, Calliobothrium schneiderae n. sp. differs from all but Calliobothrium barbarae, C. eschrichti, Calliobothrium leuckarti, and Calliobothrium hayhowi in that it is a small-bodied species that is nonlaciniate and lacks an accessory piece between the bases of its axial hooks. It differs from C. barbarae in testis number, total length, number of proglottids, and ovary shape, and differs from C. eschrichti in total length and vitelline follicle distribution. The new species also differs from C. leuckarti in total length and number of testes. It most closely resembles C. hayhowi, but differs in hook size and oncosphere packaging. The criterion suggested by Caira (1985) to distinguish axial from abaxial hooks is modified to include axial hooks being posterior in position, to accommodate species, such as C. schneiderae n. sp., in which the abaxial hooks in a pair articulate with one another along the longitudinal axis of the bothridium, rather than with their respective axial hooks. Examination of a specimen Alexander identified as Calliobothrium verticillatum suggests that this identification may also be in error, and that this large lacinate specimen of Calliobothrium also represents a new species.

A new species of Potamotrygonocestus Brooks & Thorson, 1976 (Eucestoda: Tetraphyllidea) from Plesiotrygon iwamae Rosa, Castello & Thorson (Mylliobatoidea: Potamotrygonidae) and a redescription of Potamotrygonocestus chaoi Marques, Brooks & Araujo, 2003

Potamotrygonocestus Brooks & Thorson, 1976 is currently represented by six recognised species of tetraphyllidean cestodes inhabiting Neotropical freshwater stingrays. Potamotrygonid stingrays examined to date have included only a single specimen of Plesiotrygon iwamae. Only one species of tetraphyllidean, Potamotrygonocestus chaoi Marques, Brooks & Araujo, 2003, has been described from this host, and this description was based on limited material. New efforts to document the diversity in this host species resulted in the collection of eight additional specimens of P. iwamae, one of these from the upper Rio Solimões, at São Paulo de Olivença Amazonas during September, 2003, and seven from the Baía do Marajó, Pará, during November, 2003. The specimen from the upper Solimões was found to be infected with P. chaoi. Voucher material from this stingray was used for the redescription of this cestode, which is characterized by strobila 8.78-22.83 mm long and a great number of proglottides, 58-93; the new material provided strobilar length and proglottis counts for complete worms. Potamotrygonocestus marajoara n. sp. is the second species of this genus reported from Plesiotrygon iwamae, although it appears to be restricted to the lower Amazon. This new species resembles P. chaoi in possessing filitriches and blade-like spinitriches on the scolex, cephalic peduncle and cirrus, but differs from other species of the genus in the number of testes, which is 44 on average per proglottis, and by having apical sucker measuring 95-175 microm in length. Additional data on the distribution and morphology of the microtriches and a detailed description of the female reproductive system are also provided in this study.

Ailinella mirabilis gen. n., sp. n. (Eucestoda: Pseudophyllidea) from Galaxias maculatus (Pisces: Galaxiidae) in the Andean-Patagonian region of Argentina

Ailinella gen. n. (Pseudophyllidea: Triaenophoridae) is proposed to accommodate Ailinella mirabilis sp. n. from Galaxias maculatus (Jenyns, 1842), a freshwater fish inhabiting the Andean lakes in Argentinean Patagonia. Ailinella belongs to the Triaenophoridae because it has a marginal genital pore, a follicular vitelline gland, and a ventral uterine pore. The new genus can be distinguished from other triaenophorids by the following combination of characters: a small body size, a low number of proglottides, which are longer than wide, a truncated pyramidal to globular scolex, a rectangular apical disc, presence of the neck, lack of internal longitudinal musculature separating the cortex from the medulla, testes distributed in one central field surrounding the ovary laterally and posteriorly, the vagina predominantly anterior to the cirrus sac, vitelline follicles circum-medullary, the genital pores post-equatorial, a saccate uterus, and operculate eggs. Blade-like spiniform microtriches were present on all tegument surfaces, and tumuli on all surfaces of the scolex and the anterior surface of the neck. Microtriches were characterized according to their size and density, and tumuli according to their size, inter-tumulus distance and density. Ailinella mirabilis is the first cestode described from G. maculatus and the second triaenophorid species recorded from a South American freshwater fish.

Orectolobicestus n. g. (Cestoda: Tetraphyllidea), with the description of five new species and the transfer of Phyllobothrium chiloscyllii to the new genus

ORECTOLOBICESTUS N. G. (CESTODA: Tetraphyllidea) is erected for six cestode species parasitising bamboo sharks (Orectolobiformes: Chiloscyllium). Members of this genus differ from all other phyllobothriid genera in possessing modified maisiform spinitriches on their distal bothridial surfaces. In addition, they are easily recognised in that they share the following unique combination of characters: their vitelline fields are interrupted by the ovary, their necks are scutellate, and their bothridia bear an apical sucker and marginal loculi. Five new species of Orectolobicestus are described, including O. tyleri n. sp. from Chiloscyllium punctatum off Borneo, O. lorettae n. sp. from C. cf. punctatum off Australia, O. mukahensis n. sp. and O. kelleyae n. sp. from C. indicum off Borneo, and O. randyi n.sp. from C. hasselti also from off Borneo. In addition, Phyllobothrium chiloscyllii Subhapradha, 1955 is transferred to the new genus. O. chiloscyllii (Subhapradha, 1955) n. comb. is readily distinguished from all five new species in its greater total length. In addition to a number of proglottid features, O. kelleyae n. sp. and O. randyi n. sp. clearly differ from the other three new species in their possession of trifid, rather than fully serrate, spinitriches on their proximal bothridial surfaces. The latter two species conspicuously differ from one another in total number of proglottids (11-21 vs 27-38). O. tyleri n. sp. generally has fewer proglottids than O. lorrettae n. sp. (7-17 vs 13-23) and, like O. mukahensis n. sp., possesses scutes that are spathate rather than elongate. O. tyleri n. sp. is readily distinguished from O. mukahensis n. sp. in its possession of fewer proglottids (7-17 vs. 19-29). The five new species of Orectolobicestus share derived bothridial microthrix features with Phyllobothrium squali Yamaguti, 1952, Thysanocephalum sp., Orygmatobothrium sp., Ruhnkecestus Caira & Durkin, 2006 and species of Paraorygmatobothrium Ruhnke, 1994. Among these taxa, Orectolobicestus most closely resembles Paraorygmatobothrium and Ruhnkecestus in its vitelline fields being interrupted by the ovary and the possession of a scutellate neck.

Morphological and molecular characteristics of Echinococcus multilocularis and Echinococcus granulosus mixed infection in a dog from Xinjiang, China

The Xinjiang plateau of western China has been shown to have a high prevalence for human cystic echinococcosis (CE) caused by Echinococcus granulosus, and human alveolar echinococcosis (AE) caused by Echinococcus multilocularis. The domestic dog is suspected to be the primary definitive host for the transmission of both E. granulosus and E. multilocularis to humans in this locality. Seventeen of 30 stray dogs from Hejing County of Xinjiang were found positive for E. granulosus post mortem, and one double infection was suspected. Worm samples were collected, dyed by carmine, and observed microscopically. Carmine staining examination clearly revealed the differences in number of proglottids and appearance of uterine branches and lateral genital pore for those two species of Echinococcus. Furthermore, gene target DNA fragments were amplified for formal identification of the two parasite species, based on 12 s rRNA mitochondrial gene. The PCR products were purified and sequenced. Compared with NCBI GenBank, the DNA sequences demonstrated 100% identity with E. granulosus (sheep strain, G1 genotype) and E. multilocularis.

TWO NEW SPECIES OF PARAORYGMATOBOTHRIUM (CESTODA: TETRAPHYLLIDEA) FROM WEASEL SHARKS (CARCHARHINIFORMES: HEMIGALEIDAE) OF AUSTRALIA AND BORNEO

Two new species of Paraorygmatobothrium Ruhnke, 1994, P. janineae n. sp. and P. kirstenae n. sp., are described from the spiral intestine of 2 shark species of the Family Hemigaleidae: Hemigaleus microstoma and Hemipristis elongata. The 2 new cestode species differ from other members of Paraorygmatobothrium in vitelline follicle distribution and possession of a cephalic peduncle. The 2 new species differ from 1 another in total length, maximum width, scolex size, number of proglottids per strobila, and number of testes per proglottid. The generic diagnosis of Paraorygmatobothrium is emended to include the new species. The results of this study extend the distribution of Paraorygmatobothrium to include the carcharhinid shark family Hemigaleidae.

FIVE NEW SPECIES OF ACANTHOBOTHRIUM (TETRAPHYLLIDEA: ONCHOBOTHRIIDAE) FROM THE FRESHWATER STINGRAY HIMANTURA CHAOPHRAYA (BATOIDEA: DASYATIDAE) IN MALAYSIAN BORNEO

Five new species of Acanthobothrium (Tetraphyllidea: Onchobothriidae) are described from the spiral intestine of the Freshwater whipray, Himantura chaophraya, in the Kinabatangan River in Malaysian Borneo. Based on criteria set forth in a previous categorization scheme for species of Acanthobothrium, these consist of 3 Category 1 species, Acanthobothrium asnihae n. sp., Acanthobothrium saliki n. sp., and Acanthobothrium zainali n. sp.; a Category 8 species, Acanthobothrium etini n. sp.; and a Category 2 species, Acanthobothrium masnihae n. sp.. Acanthobothrium asnihae n. sp. differs from all Category 1 species in its possession of a horizontal band of weak musculature that divides the posterior loculus in half. Among Category 1 species, A. saliki n. sp. differs from all but Acanthobothrium southwelli in its possession of postovarian testes. It differs from A. southwelli in its possession of fewer testes and a greater number of proglottids. Acanthobothrium zainali n. sp. differs from the 25 other Category 1 species in a combination of overall size, muscular pad and hook shape, arrangement and number of testes, ovary configuration in cross section, position of ovarian isthmus, and genital pore position. Acanthobothrium etini n. sp. is distinguished from all 5 other Category 8 species in its lack of testes from the proglottid antiporal and postporal regions and in testis number. Acanthobothrium masnihae n. sp. differs from the 35 other Category 2 species in its possession of fewer testes, postporal testes, or a greater number of proglottids. A key to Acanthobothrium species parasitizing H. chayophraya is presented. This represents the first report of Acanthobothrium from freshwater stingrays belonging to a family other than the Potamotrygonidae.

Two New Species of Paraorygmatobothrium (Tetraphyllidea: Phyllobothriidae) from the Lemon Sharks Negaprion brevirostris and Negaprion acutidens (Carcharhiniformes: Carcharhinidae)

Two new tetraphyllidean species, Paraorygmatobothrium roberti n. sp. and Paraorygmatobothrium arnoldi n. sp., are described from the Lemon shark, Negaprion brevirostris, and the Sicklefin lemon shark, Negaprion acutidens, respectively. The 2 species are consistent in morphology with the 5 existing species of Paraorygmatobothrium. Paraorygmatobothrium roberti n. sp. differs from existing species of Paraorygmatobothrium in features such as total length, bothridial length, apical sucker diameter, testes number, dimensions of the cirrus sac, and dimensions of the ovary. Paraorygmatobothrium arnoldi n. sp. differs from existing species of Paraorygmatobothrium in total length, proglottid width, number of proglottids per strobila, bothridial length and width, apical sucker diameter, testis number, and dimensions of the cirrus sac. The 2 new species differ from one another in total length, maximum width, and ovary length. Description of these 2 new species brings to 7 the known number of species of Paraorygmatobothrium.

Echinococcus multilocularisin Estonia

<i>Echinococcus multilocularis</i>in Estonia

Parabothriocephalus psenopsis n. sp. (Eucestoda: Pseudophyllidea) in Psenopsis anomala from the Taiwan Strait, China.

Palabothriocephalus psenopsis n. sp. (Eucestoda: Pseudophyllidea) is described from the gastrointestinal tract of Psenopsis anomala caught off the coast of Xiamen, China. The new species most closely resembles, but differs from, Parabothriocephalus segmentatus in its possession of muscular globular appendages on the posterior margin of the proglottids, a limited proglottid number (9-13), and the shorter strobila (7.6-13.2 mm vs. 165 mm). In addition, the uterus of P. psenopsis is strongly coiled, whereas that of P. segmentatus is S shaped; P. segmentatus has a spherical expansion in the middle of the vagina, whereas that of P. psenopsis does not. Finally, P. psenopsis differs from Parabothriocephalus gracilis. Parabothriocephalus sagitticeps, and Parabothriocephalus macruri by the posterolateral expansion of the proglottids.

Proterogynotaenia deblocki sp. nov. (Cestoda: Progynotaeniidae) from the Red-capped Plover, Charadrius ruficapillus, from King Island, Tasmania

A new species of cestode, Proterogynotaenia deblocki (Progynotaeniidae), is described from the Red-capped Plover, Charadrius rujicapillus, from King Island, Tasmania. The new species is characterised by its longer strobila (18-28 mm), large number of proglottids (60-85), number and size of the hooks on the rostellum (six large hooks 33-39 flm long, six small hooks 13-15 flm long) and large number of testes (62-83), which are divided by the uterus into two groups.

Two new species of Acanthobothrium Beneden, 1849 (Tetraphyllidea: Onchobothriidae) from horn sharks in the Gulf of California, Mexico.

Between 1993 and 1996, 26 individuals of two species of horn sharks were collected from the upper Gulf of California and their spiral intestines examined for onchobothriid tapeworms. Heterodontus francisci was found to host Acanthobothrium puertecitense n. sp. Based on the criteria of Ghoshroy & Caira (2001), this is a Category 4 species (with >15 mm total length, >50 proglottids, >80 testes and a symmetrical ovary). It differs from the four Category 4 species previously reported from either the western Atlantic or eastern Pacific Oceans, including A. bajaense (emend.) which was described from H. francisci, in hook-shape, total length, number of proglottids, number of testes and number of columns of vitelline follicles. H. mexicanus was found to host Acanthobothrium santarosaliense n. sp., which, based on the criteria of Ghoshroy & Caira (2001) is a Category 3 species (with >15 mm total length, >50 proglottids, >80 testes and an asymmetrical ovary). A. santarosaliense differs from the five Category 3 species previously reported from either the western Atlantic or eastern Pacific Oceans in its size, euapolytic nature, lack of dark matrix from the bases of the hooks, hook-shape, and distribution and number of testes. In addition to the difference in ovarian symmetry, A. puertecitense possesses fewer testes, fewer proglottids, is a shorter worm, possesses a more anterior genital pore and vitelline follicles which extend further forward anteriorly than in A. santarosaliense. This represents the first report of onchobothriids from H. mexicanus and the first report of onchobothriids from H. francisci in the Gulf of California. The apparent host-specificity of both new species should be viewed with caution until a greater sample of host individuals of both species can be examined. The fact that both new tapeworm species are known only from the Gulf is also considered to be a preliminary result, given the small sample of host individuals examined from these regions to date. This brings the total number of species of Heterodontus known to host Acanthobothrium to four and the total number of Acanthobothrium species described from heterodontiform sharks to five.

Allometric growth of the proglottids and strobila of the tapeworm, Hymenolepis diminuta

AbstractHymenolepis diminuta adults were killed and fixed in fully extended positions, and the total lengths of the strobilae, numbers of proglottids, and distances of proglottids along the strobilae were determined. The relationship of proglottid number to distance along the strobila was exponential. Beginning at proglottid 100 (P100), the lengths and widths of proglottids at 100 proglottid intervals were determined, and the surfaces areas were calculated. The relationships of proglottid length and width to proglottid number were linear, but the relationship of proglottid number to surface area (SA) was exponential. The volumes of proglottids were calculated, and the relationship of volume (V) to proglottid number was exponential. The relationship of surface area to volume ratio (SAVR) to proglottid number was exponential; at the anterior end of the worm (P100), the SAVR was 14.6, while at the posterior end of the worm (P1300) the ratio was 4.2. A single exponential equation describing the relationships among proglottid number, SA, and V was derived.