Metacestodes of the family Dilepididae (Cestoda: Cyclophyllidea) parasitising fishes in Mexico

A survey of metacestodes of dilepidid tapeworms (Cyclophyllidea) occurring in fish from Mexico is presented. They belong to the following species (those first reported from Mexico marked with an asterisk): Cyclustera capito (Rudolphi, 1819); ^* Cyclustera cf. ralli (Underwood & Dronen, 1986); Dendrouterina pilherodiae Mahon, 1956; ^* Glossocercus auritus (Rudolphi, 1819); ^* G. caribaensis (Rysavy & Macko, 1973); ^* Paradilepis caballeroi Rysavy & Macko, 1973; ^* Paradilepis cf. urceus (Wedl, 1855); ^* Paradilepis sp.; Parvitaenia cochlearii Coil, 1955; ^* Parvitaenia macropeos (Wedl, 1855); ^* Valipora campylancristrota (Wedl, 1855); ^* V. mutabilis Linton, 1927; and ^* V. minuta (Coil, 1950). Metacestodes of Dendrouterina papillifera (Fuhrmann, 1908), previously reported from the gall-bladder of the pimelodid catfish Rhamdia guatemalensis from Mexico by Scholz et al. (1996), belong actually to V. minuta. Data on the morphology of metacestodes, their fish hosts and rate of infection, site and distribution in Mexico are provided.     

On a life cycle of Unciunia raymondi (Cestoda: Cyclophyllidea: Dilepididae)

Cysticercoids of the cestode Unciunia raymondi Gigon et Beuret, 1991 (Cyclophyllidea: Dilepididae), a parasites of palaearctic thrushes (Turdus), taken from spontaneously infected Geotrupes and black wireworm Cylindrojulus in the North-eastern Altai, is described. An identity of cysticercoids of U. raymondi and Ditestolepis diaphana sensu Kisilewska, 1960 has been stated. During the development within the fibrillate membrane, the metacestode of U. raymondi separates the cercomer from the cyst anlage in the late scolexogenesis. There is no the primary lacuna in the lamellated cercomer without any musculature. Its primarily smooth surface gradually becomes sulcate and plicate. In the result of some segments break-up, the cercomer lamella comes to be perforated with its margins deeply jagged. Metacestode of U. raymondi metacestode is compared with cryptocercus of Dilepididae, which also develops within the fibrillate membrane. Based on peculiarities of the morphogenesis of cercomer, the cysticercoid U. raymondi is assigned to a new morpho-ecological type, the placocercus.     

Diversity of Dilepididae (Cestoda: Cyclophyllidea) revealed by cytogenetic analysis

Karyotypes of three dilepidid species: Molluscotaenia crassiscolex, Anomotaenia bacilligera and Dilepis undula, which have not been recorded previously, were studied using conventional Giemsa staining and comparative karyometric analysis. Twelve small biarmed chromosomes were observed in mitotic cells of M. crassiscolex, 16 biarmed chromosomes of gradually decreasing size were found in cells of A. bacilligera, while 18 elements were characteristic for D. undula. These data, together with information available in literature, prove the heterogeneity and possible polyphyletic nature of the family Dilepididae.     

Scolex Glands Associated with the Rostella in Three Species of the Dilepididae (Cestoda: Cyclophyllidea)

The microanatomy, fine structure and cytochemistry of scolex glands of Vitta riparia, Angularella beema and Trichocephaloidis megalocephala are examined by light and electron microscopy. Cytochemical tests include PAS, mercury bromphenol blue and performic acid-alcian blue for light microscopy and periodic acid-thiocarbohydrazide-OsO₄ for electron microscopy. The scolex glands are organized in two spatially isolated syncytia, one located in the rostellum, the other in the rostellar sac. The cytoplasm of the gland syncytia is characterized by a high affinity for haematoxylin. Cytochemical tests indicate the presence of moderate amounts of glycoprotein in the glands. A specialized type of secretion—dark oval or ovoid bodies with diameter 0.3–0.5 μm are observed by EM in both the rostellum glands and the rostellar-sac glands of V. riparia and T. megalocephala , and in the rostellar-sac gland of A. beema . The rostellum gland of A. beema produces larger dark oval bodies measuring up to 0.9 μm. Lipid droplets are also observed in the glandular cytoplasm. Some tegumental cytons containing discoid bodies are found between the glandular perikarya. The glandular products and the lipid droplets are secreted via the rostellar tegument. © 1997 Published by Elsevier Science Ltd on behalf of The Royal Swedish Academy of Sciences.     

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.     

Monocercus dokuchaevi sp. n. (Cyclophyllidea: Dilepididae)--a new species of cestodes from shrews of the North-Eastern Asia

A new cestode species, Monocercus dokuchaevi sp. n. is described from shrews of the genus Sorex from the Middle Kolyma plateau (Magadan Province). The new species is most closer to M. soricis (Neiland, 1953) by having regular alteration of genital atriums in the short strobila (up to 10 mm only). The size of rostellar hooks in M. dokuchaevi is intermedial between those in M. soricis and M. arioni (Sibold, 1850). In Monocercus dokuchaevi, the length of rostellar hooks is 0.038-0.045 mm (average 0.045 mm), in M. arioni, average is 0.05 mm, in M. soricis, limits are 0.027-0.033 mm. Two other species of the genus, M. baicalensis Eltyshev, 1971 and M. estavarensis Euzet et Jourdan, 1968, have much longer rostellar hooks, 0.07-0.08 and 0.092-0.106 mm, respectively, whereas the genital atriums in these species are altered irregularly.     

Identity of Cysticercoides menidiae Chandler, 1935 (Cestoda: Dilepididae)

Cysticercoides menidiae Chandler, 1935, described as a metacestode of an unknown dilepidid cestode from the intestinal wall and mesenteries of the silversides Menidia menidia (Pisces: Atherinidae), from Galveston Bay, Texas, was found to be conspecific with Ascodilepis transfuga (Krabbe, 1869), a tapeworm described from the spoonbill. Platalea ajaja Linnaeus (syn. Ajaja ajaja), from Brazil. Consequently. C. menidiae becomes a junior synonym of A. transfuga.     

扩张莫尼茨绦虫(绦虫纲:圆叶目)卵黄细胞发育的超微结构

用透射电镜观察了扩张莫尼茨绦虫(Moniezia expansa)卵黄细胞发育的全过程。扩张莫尼茨绦虫卵黄细胞发育的规律为：(1)细胞体积不断增大;(2)质、核比不断增加而核体积几乎不发生改变,核表面从规则变为不规则,再由不规则变为规则,核内出现染色质浓缩成小块再分散的发育变化过程;(3)线粒体逐渐增多,发育不断完善;(4)粗面内质网及高尔基复合体出现由少到多,发育不断完善,再由多到少不断退化的变化;(5)由高尔基复合体组装的电子致密的小卵黄囊不断融合,至卵黄细胞成熟时仅有一卵黄囊,占据细胞大部分体积[动物学报49(2)：256—261,2003]。     

A new species of Oochoristica (Eucestoda: Cyclophyllidea) parasite of Ctenosaura oaxacana (Reptilia: Iguanidae) from Mexico

Oochoristica whitfieldi n. sp., parasitizing the intestine of the Oaxacan black iguana Ctenosaura oaxacana (Kohler and Hasbun, 2001), in Ruinas de Guiengola, Oaxaca state, Mexico, is described. The new species can be distinguished from all 4 congenera infecting Iguanidae in the neotropical realm in possessing a lower mean number of testes (122 in O. acapulcoensis Brooks, Pérez-Ponce de León, and García-Prieto, 1999; 62 in O. guanacastensis Brooks, Pérez-Ponce de León, and García-Prieto, 1999, and 95 in O. leonregagnonae Arizmendi-Espinosa, García-Prieto, and Guillén-Hernández, 2005, vs. 35 in O. whitfieldi), and a wider scolex (0.450-0.600, 0.475-0.537, 0.5-0.8, vs. 0.25-0.26, respectively). Oochoristica iguanae Bursey and Goldberg, 1996 differs from the new Mexican species in having a longer strobila (60-110 mm vs. 14.4-33.7 mm, respectively), fewer ovarian sublobes (6 vs. 11-17), and a cirrus pouch that hardly reaches excretory canals (whereas in O. whitfieldi the cirrus pouch widely overpasses these canals).     

Peculiarities of rostellum morphology and armature in the genera Kowalewskiella and Himantaurus (Cyclophyllidea: Dilepididae)

Scoleces of two dilepidid genera, Kowalewskiella Baczynska, 1914 and Himantaurus Spasskaja et Spassky, 1971, were investigated. The rostellar hooks of both are of davaineoid type, which is quite uncommon for the family. The morphology of their rostellar apparatus, especially the form of proboscis, differs much. But when the rostellum is retracted, the crown of hooks is folded in the same manner: hooks tips assume anterior direction. The muscular system of rostellar apparatus and the transformation of scolex in the act of rostellum's retraction of Kowalewskiella finds close analogy in Aploparaksis (family Hymenolepididae s.l.), and of Himantaurus--in Paradilepis (family Dilepididae). But such morphological and functional resemblance between scoleces of Kowalewskiella and Aploparaksis from one side and of Himantaurus and Paradilepis from another is undoubtedly a result of convergence. The morphological types of rostellar hooks in these pairs of genera are very different.     

Structure of the copulative apparatus of Sobolevicanthus gracilis (Cestoda: Cyclophyllidea)

Fine structure of genital atrium, Furman body, distal region of vagina and sac cirrus were investigated. The broad polymorphism of surface microstructures (microtriches) in various parts of copulative apparatus has been revealed. The constitution of prostate glands, being the modified cytons of syncitial epithelium of the intrabursal section of spermaduct wall, is described. Based on obtained and reference data, a comparative morphological analysis of copulative apparatus organization in lowest and highest cestodes was carried out. The hypothesis suggests that evolution of its organization was connected with the reduction of the muscular elements and simultaneous improvement of their managing, their isolation from surrounding parenchyma and development of supporting connective tissue elements. It is shown, that Fuhrmann's body has its own developed muscular system armed with power microtriches and being capable to evaginate into the distal region of vagina. It is supposed that S. gracilis obtains of two different ways of copulation in: by means of cirrus that executes the cross fertilization; and by means of the additional copulative formation--Furman body, which guarantees the self fertilization of worms.     

Development of the Embryonic Envelopes of Mesocestoides lineatus (Cestoda: Cyclophyllidea)

Summary

Transmission electron microscopy revealed that the eggs of Mesocestoides lineatus consisted of an oncosphere larva surrounded by various coverings. The outermost of these was the embryonic capsule, which appeared as a thin electron-dense membranous sac. The capsule enclosed inner and outer embryonic envelopes, each of which was syncytial and apparently formed from embryonic blastomeres. The envelopes became increasingly vesiculated during embryogenesis, and were attached to each other by desmosomes by the time the larva was fully formed. An electron-dense intracellular embryophore was produced by the inner envelope; it first appeared under the distal plasma membrane as a series of blocks, which grew and fused to form a thick unbroken layer. Early in development, the proximal plasma membrane of the inner envelope was connected to the larval epithelium by a multilaminate membrane complex that was ultrastructurally similar to a continuous junction. At the end of embryogenesis, this appeared to detach from its formative cells on both sides to form the distinctive oncospheral membrane. Several eggs were bound together in clusters by a cluster capsule that was ultrastructurally identical to the individual embryonic capsules. This type of egg packaging has not been described previously for any cestode. Both the cluster and individual capsules broke down by the end of embryogenesis.     

Andracantha, a new genus of Acanthocephala (Polymorphidae) from fish-eating birds, with descriptions of three species.

Problems in taxonomy of the Polymorphidae are discussed, with particular reference to trunk spines. Andracantha gen. n. is proposed for species with genital spines and 2 fields of trunk spines. Corynosoma gravida Alegret 1941, C. mergi Lundstro?m 1941 and C. phalacrocoracis Yamaguti 1939 are redescribed and placed in Andracantha, with A. gravida (Alegret, 1941) comb. n. designated as type species.     

Cestodes of birds from the Ivory Coast. Yapolepis yapolepis n. g., n. sp., a new metadilepidid (Cyclophyllidea: Paruterinoidea) parasite of the icterine greenbul (Aves: Pycnonotidae)

Yapolepis yapolepis n. g., n. sp. a parasite of the icterine greenbul Phyllastrephus icterinus (Aves: Pycnonotidae) in the Ivory Coast is described. Due mainly to the lack of both a rostellar pouch and a paruterine organ, this new genus is classified within the family Metadilepididae Spassky, 1959. Yapolepis is principally characterised by its unarmed rostellum and by unilateral genital pores. It is assumed that the Metadilepididae are probably more diversified than presently known, the reason for this being our limited knowledge of the parasite-fauna of the intertropical terrestrial birds which are their main hosts.This work is part of the author's thesis.