Brachylepis gen. n.--a new genus of cestodes (Cyclophyllidea: Hymenolepididae) from shrews in Siberia and the Far East

A new genus Brachylepis gen. n. hymenolepididean cestodes associated with common shrews (Sorex) in Siberia and Russian Far East is created. These genus includes three species removed from the genus Mathevolepis: Brachylepis morosovi (Karpenko, 1994) comb. n. (type species), B. sorextscherskii (Morosov, 1957) comb. n. and B. triovaria Karpenko, 1990) comb. n. The new genus is characterized by the gradual strobila with a little number of segments, unarmed scolex with apical glandular organ, by lack of internal seminal vesicle and differential seminal receptacle, by form of uterus as horse shoe in young worms and buble-like in mature worms. A tendency of inverse proportional dependence between the number of uterus segments in the strobila and the number of hexacanths in the uterus has been noticed. The table of differential characters for the species of the genus Brachylepis is proposed.     

The evolution of forms of hermaphroditism in Cyclophyllidea (Cestoda). 1. Morpho-functional causes of the formation of tapeworms with the protandrous type of genital apparatus development

Morpho-fuctional causes of the formation of protandrous Cyclophyllidea (tapeworms) have been studied. Two forms of protandry are described. The protandry type I is typical for polymeric (polysegmental) Hymenolepididae. It appears independently in different taxa of this family (Aploparaksis, Echinatrium, Wardium, Diorchis and others) while the narrow-strobila forms with a low prolificacy of proglottids are formed. The development of this living form of hymenolepidids is ecologically caused by the high density of their aggregation in intestines of hosts. The primordium results in the development of genitals in the juvenile strobila proglottids with the limited internal space. Due to this process, parallel morphogenesis of male and female gonads is proved to be impossible. A selection leading to the overtaking development of testicles and copulative apparatus regarding morphogenesis of ovary and vitellarium is based an earlier maturation of testicles and group copulation of proglottids with and underdeveloped ovary that is typical in original euandrogyne forms. The group insemination of proglottids from a polysegmented strobila reduces the number of copulation and improves an efficiency of cross-copulation of tapeworms and. As a result, morpho-functional zones of male proglottids characterized by an immature ovary and those of fertile female segments losing their testicles are differentiated in the strobila. The protandry type II is typical of mesomeric tapeworms (Dilepididae, Schistotaeniidae, Anoplocephalidae). It is also resulted from a limited space of proglottids for developing the hermaphroditic genital apparatus. This is caused by the shift of genital morphogenesis process into juvenile proglottids and also by the enlargement of gonad sizes as the result of a selection for a higher prolificacy of proglottids. The dissociation of the development of male and female gonads takes place because of the retardation of ovary morphogenesis.     

Description of Paranoplocephala yoccozi n. sp. (Cestoda: Anoplocephalidae) from the snow vole Chionomys nivalis in France, with a review of anoplocephaud cestodes of snow voles in Europe

We describe Paranoplocephala yoccozi n. sp. (Cestoda: Anoplocephalidae) from the snow vole Chionomys nivalis in Bourg-Saint-Maurice, French Alps, compare it with several related species from rodents, and review the anoplocephalid cestodes of snow voles in Europe. Paranoplocephala yoccozi n. sp. is primarily distinguished from the related species by its large scolex of characteristic shape, robust neck region, and the structure of the cirrus sac, vitellarium and vagina. We show that the anoplocephalid cestodes of snow voles in Europe, representing the genera Anoplocephaloides and Paranoplocephala, include at least seven species. This fauna consists primarily of species that snow voles share with other voles inhabiting the high-mountain areas. Some of the species, including P. yoccozi n. sp., appear to have a very localized distribution, which is assumed to be a consequence of the historical fragmentation of snow vole populations.     

New species of Cinclotaenia macy, 1973 (Cyclophyllidea: Dilepididae) from Cinclus leucocephalus tschudi (Passeriformes: Cinclidae) in Bolivia

Two new species of Cinclotaenia (Cyclophyllidea: Dilepididae) are described from the small intestine of Cinclus leucocephalus (Aves: Passeriformes: Cinclidae) collected in the Yungas region of Bolivia. Cinclotaenia minuta n. sp. is characterized by possessing a minute strobila with a maximum body length of 1.58 mm, consisting of 5-10 proglottids, 19-22 rostellar hooks with lengths from 16 to 17 microm, 12-17 testes per proglottid, and eggs forming packets without filaments. Cinclotaenia boliviensis n. sp. has bandlike strobila with a length up to 26 mm with 67-74 proglittids, 22 rostellar hooks with length 39-42 microm, 43-68 testes, and eggs forming packets possessing long filaments. The systematic position in Cinclotaenia of cestodes lacking filaments on the egg packets is confirmed. This is the first record of species of Cinclotaenia in dippers from Bolivia and also the first report of cestodes from Cinclus sp. in the Neotropical Region.     

Placental Type Interactions and Evolutionary Trends of Development of Uterus in Cestodes

In Proteocephalus thymalli and P. torulosus, a contact of the placental type in uterus was shown to be formed at two different levels. At the first level an interaction occurs between outgrowths of uterine epithelium and thin capsule of embryos closely adjacent to uterine wall. The next level is formation of contact between neighboring egg capsules, which allows distributing nutrients among fetuses present in the uterine cavity. Placental interactions in Clestobothrium acheilognathi are limited in time and space. First, a relatively small number of eggs are involved in interaction of the placental type in the uterine sac, while uterine duct is filled with freely lying eggs. Second, the closest contact is observed in eggs with non-sclerosed egg shell. One of the main evolutionary tendencies in cestodes has been shown to be a modification of uterus for formation of close interrelations with embryonic membranes in the course of transition from the extrauterine to the intrauterine type of embryonic development. Uterus in parasites with a polylecital type of the egg is suggested to serve to the greater extent as a reservoir, whereas in cestodes with oligolecital eggs, uterus performs its direct function—supply of developing embryos with nutrients. As a result, modifications of uterine epithelium are formed: from the appearance of the placental type interactions formed repeatedly in phylogenetically distant groups of cestodes to formation of branched outgrowths separating the uterine space into units or disintegration to actively functioning uterine capsules.     

A new species of Linstowia (Cestoda: Anoplocephalidae) from marsupials in Bolivia.

A new species of cestode of the genus Linstowia (Cestoda: Anoplocephalidae) is described from marsupials of the genera Thylamys and Monodelphis. The new species (Linstowia schmidti) differs from Linstowia iheringi Zschokke, 1904, in having a much smaller strobila and reduced number of proglottids, and in the distribution of the eggs in gravid proglottids. In Bolivia, cestodes of the genus Linstowia appear to have a restricted geographic distribution, occurring in marsupials only in southeastern Bolivia near the western margin of the Chaco. This host-parasite association may represent an ecological-historical relict.     

Revision of the Progamotaenia zschokkei (Janicki, 1905) complex (Cestoda: Anoplocephalidae), with the description of six new species

A review of cestodes currently attributed to Progamotaenia zschokkei (Janicki, 1905) (Cestoda: Anoplocephalidae) suggests that six additional species are present: Pr. tenuis n. sp. found in Thylogale stigmatica (Gould) and T. thetis (Lesson), Pr. lomatosoma n. sp.from Macropus agilis (Gould), Pr. petrogale n. sp. from Petrogale spp. and Macropus dorsalis(Grey), Pr. fimbriata n.s p. from Lagorchestes conspicillatus Gould and L. hirsutus Gould, Pr. obesa n. sp. from Onychogalea fraenata (Gould) and O. unguifera (Gould) in north-eastern Australia and Pr. kellerae n. sp. from O. unguifera in north-western Australia. The new species are differentiated by a combination of characters: prominence of scolex lobes, number of lobes in the fimbriated velum, testis number and distribution, size of the cirrus-sac, morphology of the uterus and presence or absence of a pyriform apparatus in eggs from terminal segments. The morphological differences found support earlier molecular studies, in that cestodes within each host genus are distinct, with the exception that considerable morphological variation exists within Pr. petrogale. Principal components analysis suggested that most of the cestodes from Petrogale spp. belonged to Pr. petrogale. The status of specimens from Pe. lateralis is unclear. More detailed molecular studies are required to determine the significance of the morphological variation within this taxon. A key is provided to species within the complex and the related species Pr. villosa (Lewis, 1914).     

Comparative morphology of surface ultrastructure of diphyllobothriidean tapeworms (Cestoda: Diphyllobothriidea)

Microtriches on the scolices and adjacent strobila of seven species of diphyllobothriidean cestodes (Bothridium pithonis, Cephalochlamys namaquensis, Dibothriocephalus latus, Duthiersia expansa, D. fimbriata, Ligula intestinalis, and Schistocephalus solidus) from different hosts (frogs, snakes, lizards, birds, and mammals) and biogeographic areas were examined using scanning and transmission electron microscopy. The basic structure of the tegument of the seven species studied does not differ markedly from that found in other cestodes. The main characteristic is the presence of electron‐dense bodies and vesicles in the distal cytoplasm. However, this study has shown differences in the morphology of microtriches even among species of the same family. Two different types of microtriches were found, filitriches and spinitriches, with the latter represented by two forms. Our study reveals that capilliform filitriches are most commonly found in Diphyllobothriidea. They were observed mainly on the strobila and the scolices of all but one studied species; individuals of L. intestinalis bore only coniform spinitriches on their surface. The same type of microtriches was found on the cirrus in D. latus. Gladiate spinitriches covered the scolex in both species of Duthiersia, and gladiate spinitriches interspersed with capilliform filitriches were observed on the anterior part of the strobila in D. fimbriata and the posterior part of the scolex in B. pithonis. Individuals of C. namaquensis were covered only by small acicular filitriches. No obvious pattern in the type and distribution of microtriches was observed among species that belong to different families and parasitize distantly related definitive hosts.     

Interaction of the uterus and developing eggs in cyclophyllidean cestodes with different fecundity

The interaction of morphological changes of the uterus and fecundity of the strobilae of cestodes has been investigated. It is shown that cestodes with maximal fecundity have different and highly effective ways of supplying eggs with nutrients. It is noted that differences in fecundity of cestodes depend not only on their strategy of reproduction, ecology, and complexity of life cycles but also on the complexity of interactions between the uterus and the developing eggs.     

Systematic relationships of hymenolepidid cestodes of rodents and shrews inferred from sequences of 28S ribosomal RNA

Haukisalmi, V., Hardman, L. M., Foronda, P., Feliu, C., Laakkonen, J., Niemimaa, J., Lehtonen, J. T. & Henttonen, H. (2010). Systematic relationships of hymenolepidid cestodes of rodents and shrews inferred from sequences of 28S ribosomal RNA. —Zoologica Scripta, 39, 631–641. This study attempts to elucidate systematic relationships of hymenolepidid cestodes of rodents (18 species), shrews (13 species) and bats (one species) using sequences of partial 28S ribosomal RNA, with special reference to the genus Rodentolepis. The main finding is the presence of four multispecies clades of hymenolepidid cestodes showing pronounced morphological variation and frequent colonizations between unrelated hosts. Neither the hymenolepidid cestodes of shrews nor rodents were monophyletic. Also, the genus Rodentolepis sensu Vaucher in Czaplinski & Vaucher (1994, Keys to the Cestode Parasites of Vertebrates. Commonwealth Agricultural Bureaux International, Cambridge) is clearly non‐monophyletic. Although rostellar morphology is obviously a key feature on specific and generic levels, on higher systematic levels it seems to be a rather poor indicator of phylogenetic affinity in hymenolepidid cestodes. The presence of clades with more than one rostellar type (armed rostellum present, rudimentary unarmed rostellum present and rostellum absent) also conflicts with the proposed subfamilial and tribal classifications of hymenolepidid cestodes. The overall evidence suggests that the recent trend of splitting hymenolepidid cestodes into multiple genera will produce a more stable and practical classification than the earlier practice of favouring a few, morphologically variable genera. New classifications of hymenolepidid cestodes should, however, consider both morphological and molecular evidence.     

Ultrastructure of the reticulate uterus and specific features of matrotrophy in three species of higher cestodes (Cestoda,Cyclophyllidea)

The ultrastructure of the reticular uterus has been analyzed in pregravid and gravid proglottids of cyclophillid cestodes dwelling in water (Alcataenia dominicana and A. larina) and in terrestrial hosts (Arostrilepis tenuicirrosa). Cells of the medullary parenchyma surrounding the uterus are filled with lipid inclusions in all species investigated. The hypertrophic development of small excretory ducts that surround the uterus, contact the uterine epithelium, and penetrate the diverticula is characteristic of Alcataenia dominicana and Arostrilepis tenuicirrosa. A comparative analysis of the results and the data available for other cestode species allow for the assumption that the reticulate structure of the uterus, lipid accumulation, and contacts between the uterine epithelium and the excretory ducts are morphological and functional adaptations that enable matrotrophy and the attainment of maximal fecundity by cyclophillid cestodes.     

Redescription of Pseudanthobothrium hanseni Baer, 1956 and description of P. purtoni n. sp. (Cestoda: Tetraphyllidea) from different pairs of rajid skate hosts, with comments on the host-specificity of the genus in the Northwest Atlantic

During a parasitological survey of Leucoraja erinacea, L. ocellata, Malacoraja senta and Amblyraja radiata from Passamaquoddy Bay and waters surrounding the West Isles of the Bay of Fundy, NB, Canada, seven species of cestodes were recovered. Examination of these skates revealed the presence of two distinct species of Pseudanthobothrium Baer, 1956: one was retrieved from M. senta and A. radiata, identified as P. hanseni Baer, 1956 and redescribed herein; the other was retrieved from L. erinacea and L. ocellata and differs from previously described species. The new species is described herein as P. purtoni n. sp. on the basis of the degree of apolysis, the maximum width of the strobila, the length of the cirrus-sac and the number of testes. Additionally, the distinctiveness of both species of Pseudanthobothrium is supported by the characterisation of a 643 base-pair nuclear marker, which includes most of the D2 variable region of the large subunit ribosomal DNA (LSU). The recovery of two different tetraphyllidean species, each from two different host species, challenges the oioxeny (strict host-specificity) of echeneibothriine cestodes and can be explained, at least in part, by the similarities in diet and substrate preference within each host pair.     

The helminth parasites of the lesser flamingo,Phoeniconaias minor (Geoffroy), from Lake Nakuru,Kenya, including a new cestode,Phoenicolepis nakurensis n.g., n.sp.

Summary Seven species of cestodes and two of nematodes are reported from Phoeniconaias minor from Lake Nakuru, Kenya. Phoenicolepis nakurensis n.g., n.sp. (Hymenolepididae) is characterized by the size and shape of the hooks, scolex and strobila, structure of the terminal genital ducts, presence of an accessory sac, external seminal vesicle and stylet, and absence of an internal seminal vesicle. Gynandrotaenia stammeri. Cladogynia phoeniconaiadis, Flamingolepis tengizi, F. dolguschini and Striatofilaria phoenicopteri are redescribed; all except C. phoeniconaiadis are new for this host and for Kenya. ac]19800210Abbreviations as accessory sac - c cirrus - cs cirrus sac - esv external seminal vesicle - g gland cells - gs glandular sheath - isv internal seminal vesicle - md muscular duct - Mg Mehlis' gland - o ovary - pg prostate gland cells - s stylet - sr seminal receptacle - u uterus - v vagina - vd vas deferens - vg vitelline gland     

Molecular systematics and Holarctic phylogeography of cestodes of the genus Anoplocephaloides Baer, 1923 s. s. (Cyclophyllidea,Anoplocephalidae) in lemmings (Lemmus,Synaptomys)

The present molecular systematic and phylogeographic analysis is based on sequences of cytochrome c oxidase subunit 1 (cox1) (mtDNA) and 28S ribosomal DNA and includes 59 isolates of cestodes of the genus Anoplocephaloides Baer, 1923 s. s. (Cyclophyllidea, Anoplocephalidae) from arvicoline rodents (lemmings and voles) in the Holarctic region. The emphasis is on Anoplocephaloides lemmi (Rausch 1952) parasitizing Lemmus trimucronatus and Lemmus sibiricus in the northern parts of North America and Arctic coast of Siberia, and Anoplocephaloides kontrimavichusi (Rausch 1976) parasitizing Synaptomys borealis in Alaska and British Columbia. The cox1 data, 28S data and their concatenated data all suggest that A. lemmi and A. kontrimavichusi are both non‐monophyletic, each consisting of two separate, well‐defined clades, that is independent species. As an example, the sister group of the clade 1 of A. lemmi, evidently representing the ‘type clade’ of this species, is the clade 1 of A. kontrimavichusi. For A. kontrimavichusi, it is not known which one is the type clade. There is also fairly strong evidence for the non‐monophyly of Anoplocephaloides dentata (Galli‐Valerio, 1905)‐like species, although an earlier phylogeny suggested that this multispecies assemblage may be monophyletic. The results suggest a deep phylogenetic codivergence of Lemmus spp. and A. lemmi, primarily separating the two largely allopatric host and parasite species at the Kolyma River in east Siberia. There are also two allopatric sublineages within each main clade/species of A. lemmi and Lemmus, but the present distributions of the sublineages within the eastern L. trimucronatus and clade 1 of A. lemmi are not concordant. This discrepancy may be most parsimoniously explained by an extensive westward distributional shift of the easternmost parasite subclade. The results further suggest that the clade 1 of A. kontrimavichusi has diverged through a host shift from the precursor of L. trimucronatus to S. borealis.     

Ultrastructure of genital system ducts of Diphyllobothrium latum (Cestoda:Pseudophyllidae): the ducts of the female reproductive system

The components of the female reproductive system of Diphyllobothrium latum, including ovary, ovicapt, oviduct, vitelline ducts, vitelline reservoir, vagina, seminal receptacle, ootype with unicellular Mehlis's gland, ootype-uterine duct and uterus were observed with the electron microscope. The epithelium of the female reproductive system ducts consists of a nucleate syncytial layer. Structural differences in apical surface of the ducts, the number of nuclei and organoids in syncytial layer as well as the number of underlaid muscles were revealed. The regional differentiations of the uterus wall were registered. The middle and distal region of uterus was covered with microtriches. The filamentous microtriches were observed in apical surface of vagina. The epithelium of seminal receptacle and distal region of uterus were underlaided by the powerful muscle layers. The fertilization canal was revealed. It was shown that the formation of egg shells implemented by the deposit of vitelline globules in their surface in the ootype-uterine duct. Structural and functional differences of different parts of female apparatus in various groups of cestodes are conditioned by species biology.