Phylogenetic relationships and further unknown diversity of diplostomids (Diplostomida: Diplostomidae) parasitic in kingfishers.

Kingfishers (Alcedinidae Rafinesque) are common inhabitants of wetlands and are known to be definitive hosts to a wide range of digeneans that parasitize fish as second intermediate hosts. Among these digeneans, members of the Diplostomidae Poirier, 1886 (diplostomids) are particularly common. Recent studies of diplostomids collected from kingfishers have revealed that they are probably more diverse than currently known. This particularly concerns the genera Crassiphiala Van Haitsma, 1925 and Uvulifer Yamaguti, 1934. In the present work, we studied seven diplostomid taxa from kingfishers in Brazil, the USA and the Philippines. Partial DNA sequences of the nuclear large ribosomal subunit (28S) and mitochondrial cytochrome c oxidase I (cox1) genes were obtained, and 28S sequences were used to study the phylogenetic interrelationships of these diplostomids. We provide the first DNA sequences from Uvulifer semicircumcisus Dubois et Rausch, 1950 and a member of Subuvulifer Dubois, 1952. Pseudocrassiphiala n. gen. is erected for a previously recognized species-level lineage of Crassiphiala and a new generic diagnosis of Crassiphiala is provided. Crassiphiala jeffreybelli n. sp., Crassiphiala wecksteini n. sp. and Pseudocrassiphiala tulipifera n. sp. are described, and a description of newly collected, high-quality specimens of Crassiphiala bulboglossa Van Haitsma, 1925 (the type-species of the genus) is provided.

Phylogenetic position of Sphincterodiplostomum Dubois, 1936 (Digenea: Diplostomoidea) with description of a second species from Pantanal, Brazil.

Sphincterodiplostomum is a monotypic genus of diplostomid digeneans that parasitize fish-eating birds in the neotropics. The type species Sphincterodiplostomum musculosum has a unique, dorsal, tubular invagination in the opisthosoma with a muscular sphincter. Whereas larvae of S. musculosum are relatively commonly reported in Neotropical fish helminth surveys, adult specimens from birds are rarely collected. Prior to our study, no DNA sequence data for S. musculosum were available. Our molecular and morphological study of mature and immature adult Sphincterodiplostomum specimens from three species of birds and one species of crocodilian revealed the presence of at least two species of Sphincterodiplostomum in the neotropics. We provide the first molecular phylogeny of the Diplostomoidea that includes Sphincterodiplostomum. In addition, this is the first record of S. musculosum from caimans, along with the first record of fully mature adult S. musculosum from green kingfisher Chloroceryle americana. The new species of Sphincterodiplostomum (Sphincterodiplostomum joaopinhoi n. sp.) can be morphologically distinguished from S. musculosum based on the anterior extent of vitelline follicles, narrower prosoma, substantially smaller holdfast organ and structure of tegumental spines. Our data revealed 0.7% interspecific divergence in 28S and 10.6-11.7% divergence in cox1 sequences between the two Sphincterodiplostomum species.

Description, molecular characterization and life cycle of Serpentirhabdias mussuranae n. sp. (Nematoda: Rhabdiasidae) from Clelia clelia (Reptilia: Colubroidea) in Brazil.

Serpentirhabdias mussuranae n. sp. is described from the lungs of the mussurana, Clelia clelia (Daudin, 1803), from vicinities of Lábrea, Amazonas State, Brazil. The species is characterized by the triangular oral opening, the presence of teeth (onchia) in the oesophastome, the excretory glands longer than the oesophagus and the tail abruptly narrowing in its anterior half and gradually tapering in posterior half. Among the Neotropical representatives of the genus, three species are known to possess the onchia in the oesophastome: S. atroxi, S. moi and S. viperidicus. Serpentirhabdias mussuranae n. sp. differs from S. atroxi and S. viperidicus by its triangular shape of the oral opening and the oesophastome in apical view, vs. round in the latter two congeners. Additionally, S. viperidicus has a larger oesophastome, 13-22 micrometers wide and 13-23 micrometers deep. The new species has relatively longer excretory glands than S. moi. The new species is morphologically and genetically close to S. atroxi, S. moi and S. viperidicus, all parasitic in Brazilian snakes, based on the presence of onchia and the comparison of nucleotide sequences of nuclear ribosomal DNA and mitochondrial cox1 gene (differences varied between 3.8% and 7.1%). Data on the life cycle of S. mussuranae n. sp. is provided, and the life cycle is typical of the genus Serpentirhabdias, with the combination of direct development and heterogony. Free-living larval stages and the adults of amphimictic free-living generation are described. The results of molecular phylogenetic analysis based on nuclear ribosomal internal transcribed spacer (ITS) + partial 28S region and partial mitochondrial cox1 gene are provided.

Rhabdias glaurungi sp. nov. (Nematoda: Rhabdiasidae), parasite of Scinax gr. ruber (Laurenti, 1768) (Anura: Hylidae), from the Brazilian Amazon.

The genus Rhabdias Stiles & Hassal, 1905 includes about 83 species of nematodes parasitic in amphibians and reptiles worldwide. Herein, we describe Rhabdias glaurungi sp. nov. from the hylid frog Scinax gr. ruber (Laurenti, 1768) in the Gunma Ecological Park, Santa Bárbara municipality, state of Pará, Brazil. This species has six small lips, an inflated cuticle along the entire body and a cup-shaped buccal capsule with smooth internal surface of its anterior part and irregularly folded internal surface of its posterior part in apical view. From the 17 valid species recognized in the Neotropical realm, the new species can be distinguished by the number of lips, the morphology and size of its buccal capsule, as well as the extent and shape of its cuticular inflation; in addition, there are molecular differences. Sequences of the mitochondrial Cytochrome c Oxidase subunit I gene strongly support the status of this form as a separate species. Molecular phylogenetic analysis shows R. glaurungi sp. nov. nested within the R. pseudosphaerocephala Kuzmin, Tkach & Brooks, 2007 species complex. Rhabdias glaurungi sp. nov. is the second species of the genus described from hosts of the family Hylidae in the Neotropical realm. We conclude that the diversity of Rhabdias within the Neotropics is likely largely underestimated.

Patterns of Clinostomum marginatum infection in fishes and amphibians: integration of field, genetic, and experimental approaches.

Digenetic trematodes of the genus Clinostomum are cosmopolitan parasites infecting fishes, amphibians, reptiles, and snails as intermediate hosts. Despite the broad geographical distribution of this genus, debate about the number of species and how they vary in host use has persisted. To better understand patterns of infection among host species and across life stages, we used large-scale field surveys and molecular tools to examine five species of amphibians and seven species of fishes from 125 California ponds. Among the 12,360 examined hosts, infection was rare, with an overall prevalence of 1.7% in amphibians and 9.2% in fishes. Molecular evidence indicated that both groups were infected with Clinostomum marginatum. Using generalized linear mixed effects models, host species identity and host life stage had a strong influence on infection status, such that Lepomis cyanellus (green sunfish) (49.3%) and Taricha granulosa (rough skinned newt) (9.2%) supported the highest overall prevalence values, whereas adult amphibians tended to have a higher prevalence of infection relative to juveniles (13.3% and 2.5%, respectively). Experimentally, we tested the susceptibility of two amphibian hosts (Pseudacris regilla [Pacific chorus frog] and Anaxyrus boreas [western toad]) to varying levels of cercariae exposure and measured metacercariae growth over time. Pseudacris regilla was 1.3× more susceptible to infection, while infection success increased with cercariae exposure dose for both species. On average, metacarcariae size increased by 650% over 20 days. Our study highlights the importance of integrating field surveys, genetic tools, and experimental approaches to better understand the ecology of host-parasite interactions.

Digeneans of northern fur seals Callorhinus ursinus (Pinnipedia: Otariidae) from five subpopulations on St. Paul Island, Alaska.

A parasitological survey of 651 northern fur seals Callorhinus ursinus L. from five subpopulations was conducted on St. Paul Island, Alaska, during July-August 2012-2014. Digenean trematodes were found in 210 of 651 fur seals with a total prevalence of 32.3%. Intensity of infection varied from 1 to 1540 parasites with mean intensity 18.4 ± 111.1 SD and median intensity of 2 specimens per host. Significant differences in prevalence and intensity of infection in northern fur seals between separate rookeries was not observed (Mann-Whitney test; p > 0.05). Four species of digeneans belonging to the families Heterophyidae (Apophallus zalophi Price, 1932, Phocitrema fusiforme Goto and Ozaki, 1930, and Galactosomum ubelakeri (Dailey, 1969)) and Troglotrematidae (Nanophyetus salmincola (Chapin, 1926)) were found. Nanophyetus salmincola is reported from C. ursinus for the first time. We obtained partial 28S rDNA sequences for all digenean species and conducted molecular phylogenetic analysis to demonstrate their phylogenetic relationships.

Genetic divergence of human pathogens Nanophyetus spp. (Trematoda: Troglotrematidae) on the opposite sides of the Pacific Rim.

Human and animal nanophyetiasis is caused by intestinal flukes belonging to the genus Nanophyetus distributed on both North American and Eurasian coasts of Northern Pacific. In spite of the wide geographical distribution and medical and veterinary importance of these flukes, the intra-generic taxonomy of Nanophyetus spp. remains unresolved. The two most widely distributed nominal species, Nanophyetus salmincola and Nanophyetus schikhobalowi, both parasitizing humans and carnivorous mammals, were described from North America and eastern Eurasia, respectively. However, due to their high morphological similarity their interrelationships remained unclear and taxonomic status unstable. In this study, we explored genetic diversity of Nanophyetus spp. from the Southern Russian Far East in comparison with that of samples from North America based on the sequence variation of the nuclear ribosomal gene family (18S, internal transcribed spacers, ITS1-5·8S-ITS2 and 28S). High levels of genetic divergence in each rDNA region (nucleotide substitutions, indels, alterations in the secondary structures of the ITS1 and ITS2 transcripts) as well as results of phylogenetic analysis provided strong support for the status of N. salmincola and N. schikhobalowi as independent species.

Insights on the host associations and geographic distribution of Hymenolepis folkertsi (Cestoda: Hymenolepididae) among rodents across temperate latitudes of North America.

Synoptic data and an understanding of helminth parasite diversity among diverse rodent assemblages across temperate latitudes of North America remain remarkably incomplete. Renewed attention to comprehensive survey and inventory to establish the structure of biodiverse faunas is essential in providing indicators and proxies for identifying the outcomes of accelerating change linked to climate warming and anthropogenic forcing. Subsequent to the description of Hymenolepis folkertsi in the oldfield mouse, Peromyscus polionotus, additional specimens of hymenolepidids were collected or discovered in archived museum repositories from multiple species of deer mice (Peromyscus maniculatus, Peromyscus leucopus), the golden mouse (Ochrotomys nuttalli), chipmunks (Tamias striatus, Tamias amoenus), the 13-lined ground squirrel (Ictidomys tridecemlineatus), and tree squirrels (Sciurus carolinensis, Sciurus niger) from disjunct localities in the USA spanning southern Georgia, Virginia, Pennsylvania, Connecticut, the Upper Peninsula of Michigan, Wisconsin, and central Idaho. Specimens were largely consistent morphologically with the original description of H. folkertsi. Initial DNA sequence data, from a portion of the mitochondrial NADH dehydrogenase subunit 1, demonstrated intraspecific variation among three apparently geographically isolated populations attributed to H. folkertsi (uncorrected genetic distances of 2.7 % (Idaho and Michigan), 2.4 % (Virginia + Pennsylvania and Michigan), and 1.89 % (VA + PA and ID). Geography rather than host association explains the distribution and occurrence of H. folkertsi, and host colonization among deer mice, chipmunks, and other sciurids within regional sites is indicated. Genetic divergence revealed across localities for H. folkertsi suggests historically isolated populations, consistent with extended evolutionary and biogeographic trajectories among hymenolepidids and species of Peromyscus and Tamias in North America. Field inventory, that revealed these parasite populations, substantially alters our understanding of the distribution of diversity and provides insights about the nature of the complex relationships that serve to determine cestode faunas in rodents.

Ecological, morphological, and molecular studies of Acanthocheilonema odendhali (Nematoda: Filarioidea) in northern fur seals (Callorhinus ursinus) on St. Paul Island, Alaska.

Studies of northern fur seal (Callorhinus ursinus Linnaeus, 1758) infection by the filariid nematode Acanthocheilonema odendhali were carried out in 2011-2012 on St. Paul Island, Pribilof Archipelago, Alaska. Skins of 502 humanely harvested northern fur seals from haul-out areas of five rookeries, Polovina (n = 122), Morjovi (n = 54), Zapadni (n = 72), Lukanin (n = 109), and Gorbatch (n = 145), were examined. A. odendhali was found in 18% of northern fur seals. The prevalence of infection ranged from 12.5% up to 22.9% on different haul-out areas on the island. The mean intensity of infection was 1.3 (range 1-7). Detailed morphological examination of collected specimens was performed using light microscopy. Several characters were added to the morphological description of the species, among them lateral thickening of the body cuticle, especially prominent in males, variations in number and position of genital papillae in males, transverse striation of the cuticle, and terminal dilation on tail end in microfilariae. The adult specimens studied had a shorter esophagus than type specimens from the California sea lion described by Perry (1967). Comparison of partial sequences of the mitochondrial cox1 gene from specimens collected from five sampling sites on St. Paul Island and a specimen from the type host and territory in California showed no significant differences and strongly supported conspecificity of the material from Alaska with A. odendhali.

[Anatomical and clinical characteristics of the chorda tympani]. / Anatomo-klinicheskaya kharakteristika barabannoi struny.

The article presents information about the applied and clinical anatomy of the chorda tympani. Brief information is given about the history of its discovery, embryonic and postnatal development, features of anatomy, topography and morphology. The clinical aspects of the lesion and methods of studying the function of the chorda tympani are described.

[Franciscus Silvius (1614-1672) and his contributions to neuroanatomy and clinical medicine]. / Frantsisk Sil'vii (1614­1672) i ego vklad v neiroanatomiyu i klinicheskuyu meditsinu.

The article is dedicated to the 350th anniversary of the death of the Dutch anatomist, physiologist, yatrochemist and the greatest physician of the XVII century, Franciscus Sylvius (Franz de le Boe) (1614-1672). His contribution to the study of the structure of the nervous system is characterized, as well as the main scientific discoveries and achievements in building a rational system of medical science and practice. It is stated that eponym «aquaeductus Sylvii¼ was coined by Lorenz Heister in 1717 in his paper «De admiranda cerebelli structura¼.

[Modern ideas on trigeminal ganglion]. / Evolyutsiya predstavlenii o troinichnom uzle.

The article summarizes data about the structural and functional organization of the sensory ganglion of V cranial nerve - trigeminal, or Gassesrian, ganglion. Information about its discovery, embryonic development, anatomy and topography, features of cyto- and histoarchitectonics are given, the role of neurotransmitters of trigeminal ganglion neurons in nociception mechanisms is reflected, the functional significance of the trigeminal system and clinical aspects of the lesion of the Gasserian ganglion are described.

Two New Species of Staphylocystoides Yamaguti, 1959 (Cyclophyllidea: Hymenolepididae) from the Masked Shrew Sorex cinereus in North America.

Two new species of Staphylocystoides are described from masked shrews Sorex cinereus. Staphylocystoides oligospinosus n. sp. was collected from the vicinity of Missoula, Montana, United States, and Staphylocystoides parasphenomorphus n. sp. was collected from the vicinity of Whitehorse, Yukon Territory, Canada. Morphological differentiation from known species is provided. Both species are morphologically closest to Staphylocystoides sphenomorphus and to each other. Among other characters, S. oligospinosus n. sp. can be easily differentiated from all known species of the genus by unique cirrus armature, which consists of a short zone of small spines at the base of the cirrus, a few large sparsely distributed spines of varying size in the middle part of the cirrus, and hair-like microtriches densely covering the apical portion of the cirrus. Staphylocystoides parasphenomorphus n. sp. differs from S. oligospinosus n. sp. in a number of characters, most distinctly in cirrus armature, and from another morphologically similar species, S. sphenomorphus, in the number of proglottids, strobila size, number and size of rostellar hooks, and relative length of cirrus sac. Comparison of partial sequences of nuclear large ribosomal RNA subunit gene (1,310 base pairs [bp]) and mitochondrial NAD(P)H dehydrogenase subunit 1 gene (710 bp) strongly supports the status of the described forms as new species. This increases the number of Staphylocystoides species known in North America to 9 (5 parasitizing S. cinereus) and the total number of species in the genus to 12. Staphylocystoides parasphenomorphus n. sp. is the first named Staphylocystoides record in Canada.

First Record of Leucocytozoon (Haemosporida: Leucocytozoidae) in Amazonia: Evidence for Rarity in Neotropical Lowlands or Lack of Sampling for This Parasite Genus?

Birds harbor an astonishing diversity of haemosporidian parasites belonging to the genera Haemoproteus, Leucocytozoon, and Plasmodium. Currently there are more than 250 morphologically described avian haemosporidian species and 2,828 unique lineages found in virtually all avian clades and zoogeographic regions, except for Antarctica. Our report is based on PCR and microscopic screening of 1,302 individual avian samples from Brazil to detect the underrepresented genus Leucocytozoon. This survey primarily focuses on passerine birds collected from Amazonia, the Atlantic Rain Forest, and Pantanal. We also summarize studies conducted in Brazil that report haemosporidian prevalence using both microscopy and molecular tools and present for the first time a record of Leucocytozoon infecting an avian host population in Amazonia. Based on our findings, we suggest that high average temperatures may be constraining both the distribution and diversity of Leucocytozoon in lowland tropical South America.

Phylogeny and classification of the Digenea (Platyhelminthes: Trematoda).

Complete small subunit ribosomal RNA gene (ssrDNA) and partial (D1-D3) large subunit ribosomal RNA gene (lsrDNA) sequences were used to estimate the phylogeny of the Digenea via maximum parsimony and Bayesian inference. Here we contribute 80 new ssrDNA and 124 new lsrDNA sequences. Fully complementary data sets of the two genes were assembled from newly generated and previously published sequences and comprised 163 digenean taxa representing 77 nominal families and seven aspidogastrean outgroup taxa representing three families. Analyses were conducted on the genes independently as well as combined and separate analyses including only the higher plagiorchiidan taxa were performed using a reduced-taxon alignment including additional characters that could not be otherwise unambiguously aligned. The combined data analyses yielded the most strongly supported results and differences between the two methods of analysis were primarily in their degree of resolution. The Bayesian analysis including all taxa and characters, and incorporating a model of nucleotide substitution (general-time-reversible with among-site rate heterogeneity), was considered the best estimate of the phylogeny and was used to evaluate their classification and evolution. In broad terms, the Digenea forms a dichotomy that is split between a lineage leading to the Brachylaimoidea, Diplostomoidea and Schistosomatoidea (collectively the Diplostomida nomen novum (nom. nov.)) and the remainder of the Digenea (the Plagiorchiida), in which the Bivesiculata nom. nov. and Transversotremata nom. nov. form the two most basal lineages, followed by the Hemiurata. The remainder of the Plagiorchiida forms a large number of independent lineages leading to the crown clade Xiphidiata nom. nov. that comprises the Allocreadioidea, Gorgoderoidea, Microphalloidea and Plagiorchioidea, which are united by the presence of a penetrating stylet in their cercariae. Although a majority of families and to a lesser degree, superfamilies are supported as currently defined, the traditional divisions of the Echinostomida, Plagiorchiida and Strigeida were found to comprise non-natural assemblages. Therefore, the membership of established higher taxa are emended, new taxa erected and a revised, phylogenetically based classification proposed and discussed in light of ontogeny, morphology and taxonomic history.

Intraspecific variability among NADH dehydrogenase subunit 1 sequences of Taenia hydatigena.

This paper describes intraspecific variability of the partial sequences of the mitochondrial ND1 gene among isolates of Taenia hydatigena from pigs in Poland, Ukraine and Wales. The differences between studied isolates ranged from 0.4 to 5.5%, which exceeds the variability within the same fragment between the different genetic variants of Echinococcus multilocularis and is comparable with the variability between the most closely related strains (G5/G6/G7) of E. granulosus. The biggest difference (5.5%) was found between the geographically most distant Ukrainian and Welsh samples of T. hydatigena while the samples collected from the neighbouring locations in Poland, were most similar to each other.

Maritrema neomi n. sp. (Digenea: Microphallidae) from water shrews (Neomys).

Maritrema neomi n. sp. is described based on specimens found in the intestine of the Mediterranean water shrew (Neomys anomalus) from the Ukrainian part of the Carpathian Mountains. The most important diagnostic features of M. neomi are the body size, sucker ratio, shape and length of the cirrus sac, the cirrus sac/body length ratio, and the topography of the intestinal ceca. Maritrema neomi differs from Maritrema carpathica in the length and shape of body, size of eggs and vitelline follicles, and length of uterus; from Maritrema feliui, in length of cirrus sac, the cirrus sac/body length ratio, and length of intestinal ceca; from Maritrema pyrenaica, in the suckers ratio, shape of body, and size of some internal organs; and from metacercariae of Maritrema galloprovinciale, by much smaller size of body and internal organs, size of vitelline follicles, and topography of the vitellarium. The life cycle of M. neomi involves as intermediate hosts prosobranch snails (Terrestribythinella) and gammarid crustaceans (Gammarus (Rivulogammarus) balcanicus).

Phylogenetic and biogeographical relationships among some holarctic frog lung flukes (Digenea: Haematoloechidae).

A phylogenetic study of 8 North American and European species of frog lung flukes belonging to Haematoloechus was conducted using approximately 850 to 1,000 bases of the intemal transcribed spacer region (ITS 1 + 5.8S + ITS 2) and 1,250 bases of the large subunit (LSU) of the nuclear ribosomal DNA. Adequate phylogenetic resolution could not be obtained from 5.8S or ITS 2 data. Analysis of ITS 1 data produced 2 equally parsimonious trees that differed only in the position of Haematoloechus breviplexus relative to H. medioplexus and H. varioplexus. Single, identical trees were produced by analysis of both LSU sequence data and a data set comprised of all ITS and LSU data. All trees demonstrated 3 distinct evolutionary lineages within the Holarctic Haematoloechus examined. The results confirmed the taxonomic validity of H. abbreviatus and demonstrated that the presence or absence of extracecal uterine loops is not a character meaningful to the recognition of evolutionary lineages or differentiation of genera. Examination of ITS sequence data revealed almost no intraspecific variation within 5 species of Haematoloechus and demonstrated an approximately 150-base indel common to the North American H. longiplexus and the European H. asper. Two of 3 clades revealed by the phylogenetic analyses are comprised of both European and North American species, indicating that lineages of Haematoloechus arose before the breakup of Laurasia and radiated after Eurasia and North America split. Within each of 3 evolutionary lineages, members share similar patterns of arthropod host specificity distinct from patterns found in the other lineages. This suggests that second intermediate host specificity may be a trait that has been conserved through evolutionary time.

Scanning electron microscopy of the rare nematode species Pterygodermatites bovieri (Nematoda:Rictatuliriidae), a parasite of bats.

External morphology of the nematode Pterygodermatites bovieri (Blanchard, 1886), a very rare parasite of bats in the Palaearctic region, was studied by scanning electron microscopy. Special attention was paid to the cephalic end structure and cuticular armament, which are of great systematic importance in this group of nematodes. The mouth opening of P. bovieri is subterminal and oriented dorsally. Numerous sclerotized denticles, arranged in two rows, are situated in the buccal cavity around the mouth opening. They are better developed in its ventral part. In females there are 12-14 ventral denticles. Cephalic papillae are arranged in two rows: internal (six papillae--two dorsal, two lateral and two ventral) and external (four papillae). Amphids are small, situated close to lateral, cephalic papillae of the internal row. Males possess 40-41 cuticular combs in each ventro-lateral plate row, and, in addition, a short row of four ventral, unpaired precloacal fans. Females in our material possessed 68 cuticular elements represented by combs and spines, in each row. Changes of the cuticular elements shape along the nematode body length are described. Results of SEM observations are compared with previous descriptions of P. bovieri based on the light microscopical observations.

Description of cysticercoid of Coronacanthus vassilevi Genov, 1980 (Cestoda:Hymenolepididae).

Genus Coronacanthus Spassky, 1954 contains three species--C. integra (Hamann, 1891), C. omissa (Baer et Joyeux 1943) and C. vassilevi Genov, 1980--but larval stages of only first two species were described before. During 1991-1993 cysticercoids of all three species were found from gammarid crustaceans in Eastern Carpathians. The article contains an illustrated description of the cysticercoid of C. vassilevi. It differs considerably from the formerly known Coronacanthus larvae by the egg-shaped (not lens-shaped) form of the cyst, absence of marginal thickening of the cyst wall, by the shape and length of cercomer and besides, by the invagination of the anterior part of the scolex. Microvilli on the cyst surface were not detected with light microscope. Cercomer of C. vassilevi is narrow and very long as for mammalian hymenolepidid (4.7 to 8 times longer than cyst). The number (37-38), length (8-9 microns) and shape of rostellar hooks well correspond to those of adult worms (Genov, 1980).