[On the life cycle and morphology of metacestodes Dioecocestus asper (Cyclophyllidea: Dioecocestidae)].

Metacestodes Dioecocestus asper (Cyclophyllidea) habe been found in larvae of dragonflies Aeshna spp. (Odonata, Anisoptera) from the lakes of the Upper Kolyma and northern Okhotsk seaboard basins (3.8 +/- 0.46 % of n = 1730 and 0.09 +/- 0.09 % of n = 1065, respectively) for the first time. Thus, participation of dragonflies in lifecycle of Dioecocestidae has been proved. Larvagenesis of D. asper (from spontaneously infested hosts) have been retraced from the stage of primary lacuna up to fully-developed metacestode. Process of development of the metacestode D. asper includes two invaginations. The first one follows the start of exogenous formation of undifferentiated anlage of the cystoscolex; as the result, the latter settles to the bottom of the forming two-layered exocyst homologous to the cercomer. Subsequent development of the prospecive part and the endocyst occurs in the closed amniotic cavity of the sacciform exocyst, the back pole of which preserves embryonic hooks and the front pole possesses the invaginational channel. At the stage of early scolexogenesis, the endocyst with the anlage of the strobila and the scolex separates from the exocyst and the excretory atrium forms on the back pole of endocyst. At the stage of late scolexogenesis, the formation of the larval strobila (differentiation of the sex) is completed and the second invagination starts. Strong retractors pull bottom of the stribila into the endocyst; simultaneously, the front part of it is also turned inside. The invaginational pore of the endocyst of fully-developed metacestode D. asper remains open; the scolex with the most part of the strobila is located outside the endocyst in the cavity of the exocyst. The encystment of the metacestode occurs when the temperature rises up to 40 degrees C (i. e., reaching the temperature of the definitive host). Morphogenesis of the uniquely large (among the cyclophyllid metacestodes developing in the invertebrate intermediate host) metacestode D. asper lasts for about two--three years and is associated with the developmental terms of the intermediate host, the larva of the Aeshna dragonfly, in climatic conditions of the Far North-East of Asia. Early stages of morphogenesis of D. asper were noted at the dragonfly larvae of the age of 0+ (at September) and 1+ (at June), and fully-developed metacestodes, only at elder ages. Owing to the extremely large size of D. asper metacestodes we refer them as a specific modification of cysticercoids: a megalocercus (Megalocercus). Common features were noted in the structure and morphogenesis of D. asper megalocercus and ascocerci of Schistotaeniidae. High morphological similarity of these metacestodes and their development in relative taxonomic groups of intermediate hosts, larvae of amphibiotic insects (the dragonfly larvae, and occasionally the larvae of mayflies or water-bugs), prove their belonging to the same philogenetically related group of metacestodes Cyclophyllidea, emerging independently from other groups of cysticercoids. We suggest naming this morpho-ecological group of larvocysts as ascocerci (or ascocysticercoids). The use of the name "ascocercus" as nominal nomenclature for group of larvocysts supposes the change of the name "ascocercus Schistotaeniidae" to "euascocercus".

[Soricinia sawadai sp. n. (Cyclophyllidea: Hymenolepididae), a new cestode species from the shrews of Sakhalin Island].

A new species Soricinia sawadai sp. n. parasitizing shrews of Sakhalin Island (Sores unguiculatus and S. caecutiens) is described. The new species differs from other species of the genus Soricinia Spassky et Spasskaja, 1954 in having specific armament and size of the cirrus. Soricinia sawadai sp. n. differs from S. aurita (Irzhavsky et al., 2005) in having half size of the ovary (0.076-0.08 x 0.03-0.038 versus 0.135-0.14 x 0.037-0.04) and the cirrus bursa extending into the aporal fraction of the middle part of segment. The new species differs from S. quarta (Karpenko, 1983) in having half size of the cirrus (0.025-0.026 versus 0.05-0.055) and half number of hexacants in uterine segments (20-22 versus 40-45). The new species differs from S. infirma (Zarnowski, 1955) in having other cirrus armament, larger number of segments and lesser number of hexacants. The species Insectivorolepis macracetobulosa Sawada et Koyasu, 1991 parasitizing Sorex unguiculatus on Hokkaido Island is synonymized with Soricinia quarta. The species Insectivorolepis macracetobulosa sensu Sawada et Harada, 1993 parasitizing Sorex shinto shinto on Honshu Island is described as a separate species Soricinia haradai sp. n.

[A new species of cestode, Vampirolepis insula sp. n. (Cyclophyllidea: Hymenolepididae) from bats of the Sakhalin and Kunashir islands].

Description of a new cestode species Vampirolepis insula sp. n. parasitizing Ambliotus nilssonni (Keyserling et Blasius, 1839 and Plecotus auritus Linnaeus, 1758 from the islands Sakhalin and Kunashir is given. The new species is closely related to the species group within the genus Vampirolepis having 30 rostellar hooks 0.020-0.022 mm length with the blades shorter than guard. The group includes V. balsaci (Joyeux et Baer, 1934) Spassky, 1954, Sawada, 1974 and V. ozensis Sawada, 1974. The main differential character of the new species is the position of genital pores on the left side of proglottides. Moreover, the new species differs from V. balsaci and V. ozensis by almost twice larger size ofscolex, suckers, and rostellum. Vampirolepis insula sp. n. also differs from V. ogaensis and V ozensis by a larger size of ovary and vitelline gland.

[Morphogenesis of the Staphylocystis furcata cysticercoid (Cyclophyllidea, Hymenolepididae)].

The morphogenesis of the Staphylocystis furcata (Stieda, 1862) cysticercoids has been studied in the experimentally infected beetles Geotrupes stercorosus and their structural and ontogenetic features have been described. At the initial stage of its development metacestode of S. furcata forms lacuna primitiva. The primordium of scolex invaginates early into the posterior part of the larva, and then the scolex develops in the cyst cavity. There is only an anterior obturator valve developing in the cyst. Posterior obturator valve is absent, that results in the cyst remaining unlocked and the cercomer does not separate from the cyst. There is no lacuna primitiva in the cercomer. The tegument of metacestode gets covered with a solid fibrous layer at the final stage of morphogenesis. It makes the cyst partly or completely pressed in the anterior part of the cercomer when it grows. The similarity between S. furcata cysticercoids and morphologically related cysticercoids Hymenolepididae has been analysed.

[Pararodentolepis gen. n., a new genus of cestodes from rodents, with the description of P. sinistra sp. n. (Cyclophyllidea: Hymenolepididae)].

A new cestode genus and speies with armed scolex, Pararodentolepis sinistra gen. et sp. n. (Cyclophyllidea: Hymenolepididae), is described ex brown rat Rattus norvegicus Berkentheut, 1769 from the western Siberia. The differential diagnosis is also given.

[Relictolepis gen. n.--a new cestode genus (Cyclophyllidea: Hymenolepididae) from rodents of the Russian Far East and the description of R. feodorovi sp. n].

A new cestode genus and species Relictolepis feodorovi gen. et sp. n. having armed scolex is described ex Clethrionomis rufocanus Sundevall, 1846 (Rodentia, Microtinae) from the Russian Far East.

[On the species independence of Mathevolepis larbicus Karpenko, 1982 (Cyclophyllidea, Hymenolepididae, Ditestolepidini)].

The cestode species Mathevolepis larbicus Karpenko, 1982 parasitizing shrews in Russian Far East is restored. As the holotype was lost, the neotype is selected. The redescription and differential diagnosis of the species are given.

[Influence of the phase of the number and demographic structure of the water vole population on its infection by helminthes].

In this work we have analyzed results of the long-term investigations of the helminthes distribution in the various demography groups of the water vole population (Arvicola terrestris L.) in North Baraba (Novosibirsk region). The data on the dominant parasites of these rodents: trematodes Notocotylus noyeri (Joyeux, 1922), cestodes Limnolepis transfuga Spassky et Merkuscheva, 1967, nematodes Capillaria wioletti Ruchljadeva, 1950, Longistriata minuta (Dujarden, 1845) and Heligmosomum costellatum (Dujarden, 1845) have shown that the number of parasites in biocenosis are connected with different factors, such as the demographic structure of the host population, the alternation of hosts number and conditions of the environment (dry and damp phases of the climatic cycle). In the dry phase the main parasitize load N. noyeri, L. transfuga and C. wioletti connects with the breeding group; in the damp period - with immature rodents. Independently of the phase climatic cycle and the density of the water vole population the great bulk of nematodes L. minuta and H. costellatum was uncovered of the immature individuals. In any case the number of helminthes changed synchronously with such of the its host.

[The evolution of the forms of hermaphroditism in Cyclophyllidea (Cestoda). 2. Morphofunctional causes of the formation of tapeworms having a protogynous type of the genital apparatus development].

Morpho-biological causes of the formation of protogynous forms of Anoplocephalidae (Cyclophyllidea) parasitizing rodents have been studied. The reduction in the number of segments in the strobila of anoplocephalideans (Anoplocephaloides, Paranoplocephaloides) in comparison with related polymeric species of the taxon (Paranoplocephala) suggests that protogyny is resulted from the secondary oligomerization of strobila in the phylogenesis of these cestodes. It is evident that the ecological cause of the selection for a small number of segments in the strobila is a tough competition among large polymeric cestodes that results in the formation of small anoplocephalideans located in the back part of the small intestine (Paranoplocephaloides) and in the blind gut (Anoplocephaloides) of rodents. There is slowing down of strobilation rates, acceleration of genital apparatus development and somatic proglottid morphogenesis during the change into protogyny. Due to an earlier, regarding testicle morphogenesis, formation of the ovary and uterus, uterus segments are developing most of the time in the strobila. Thus, proterogyny is one of the universal mechanisms to extend the terms of hexacanth embryogenesis in the second oligomeric strobila of tapeworms.

[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.

[Monocercus dokuchaevi sp. n. (Cyclophyllidea: Dilepididae)--a new species of cestodes from shrews of the North-Eastern Asia]. / Novyi vid tsestod--Monocercus dokuchaevi sp. nov. (Cyclophyllidea: Dilepididae) ot zemleroek Severo-Vostochnoi Azii.

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.

[Mathevolepis junlanae sp. n. (Cyclophyllidea: Hymenolepididae: Ditestolepidini), a new cestode species from shrews of Far East]. / Mathevolepis junlanae, sp. n. (Cyclophyllidea: Hymenolepididae: Ditestolepidini)--novyi vid tsestod ot zemleroek Dal'nego Vostoka.

Mathevolepis junlanae sp. n. from shrews (Sorex spp.) of Far East is described given. The new species occupies an intermediate position between the Palaearctic species M. petrotschenkoi Spassky, 1948 (total number of proglottids--4) and M. skrjabini (Sadovskaya, 1965) (10-12 segments in a series) by the number of synchronously developing proglottids (2-4). The new species differs from M. larbi Karpenko, 1982 by the structure and measurements of copulative apparatus in proglottids. In M. larbi, vagina S-shaped, vagina length 0.147-0.154 mm, cirrus length 0.146-0.149 mm, and cirrus bursa reaching aporal excretory vessels. M. junlanae sp. n. has cirrus bursa slightly crossing center line of sexually mature proglottids, cirrus about half as long (0.084-0.092 mm), and smaller sac-shaped vagina (0.075-0.10 mm). The new species differs from the Nearctic representative M. macyi (Locker and Rausch, 1952) by lesser measurements of cirrus bursa (0.12-0.14 mm versus 0.4 mm) and a fewer number of proglottids in series (2-4 versus 5-7).

[On a life cycle of Unciunia raymondi (Cestoda: Cyclophyllidea: Dilepididae)]. / O zhiznennom tsikle 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.

[A new cestode species Paranoplocephala gubanovi sp.n. (Cyclophyllidea: Anoplocephalidae) from the wood lemming Myopus schisticolor of eastern Siberia]. / Novyi vid tsestody Paranoplocephala gubanovi sp. n. (Cyclophyllidea: Anoplocephalidae) ot lesnogo lemminga Myopus schisticolor Vostochnoi Sibiri.

A new species of anoplocephalid cestode, Paranoplocephala gubanovi sp. n. (Cyclophyllidea, Anoplocephalidae), from wood lemmings of Eastern Siberia (Myopus schisticolor) is described. The new species differs from other known species of Paranoplocephala associated with Holarctic lemmings by having unique combination of characters as follows: a few-segmented strobila, superficial suckers sticking out of the scolex, ovary covering practically the whole middle part of the segment, relatively little number of testicles situated in the aporal part of the segment, cirrus bursa crossing the poral excretory vessels, and subspherical spermatheca situated in the middle part of the segment. Comparison of P. gubanovi sp. n. and several closest species, P. fellmani Haukisaimi et Henttonen, 2001, P. serrata Haukisaimi et Henttonen, 2000, and P. arctica (Rausch, 1952) has been carried out. Features distinguishing the new species from Aprostatandrya macrocephala and A. microti have also been studied.

[Brachylepis gen. n.--a new genus of cestodes (Cyclophyllidea: Hymenolepididae) from shrews in Siberia and the Far East]. / Brachylepis gen. n.--novyi rod tsestod (Cyclophyllidea: Hymenolepididae) ot zemleroek Sibiri i Dal'nego Vostoka.

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.

[Paranoplocephala longivaginata sp. n. (Cyclophyllidea: Anoplocephalidae)--a new cestode from rodents of the Western Siberia]. / Paranoplocephala longivaginata sp. n. (Cyclophyllidea: Anoplocephalidae)--novaia tsestoda ot gryzunov Vostochnoi Sibiri.

A new species of anoplocephalidean cestode Paranoplocephala longivaginata sp. n. from some rodents (Clethrionomys rutilus, Sciurus vulgaris) of the Western Siberia is described. The new species differs from formerly known species of the genus Paranoplocephala by a structure of copulatory organs: the length of cirrus and the length of vagina exceed the length of genital bursa more than 1.5 times; the internal surface of the vagina is covered with hair-like bristles along all its length.

[The taxonomic independence of Anoplocephaloides spp. (Cestoda: Anoplocephalidae) with serial alternation of the genital atria]. / O taksonomicheskoi samostoiatel'nosti Anoplocephaloides spp. (Cestoda: Anoplocephalidae) s seriinym cheredovaniem polovykh atriumov.

The mutual dispositions of the genital apertures in the anoplocephalidean strobila and their taxonomical significance were considered. The irregular alternations of single genital apertures from the alternations of its seria on the proglottid margins could be distinguished. The serial alternation as an intermediate type in the transformation from the irregular to unilateral dispositions of the genital apertures were considered. The conclusion about the Anoplocephaloides spp. with the serial alternations of genital apertures as a separate taxon was presented. The validity of the genus Gallegoides was renewaled. New genus Paranoplocephaloides gen. n. and a new species P. schachmatovae sp. n. from the voles Microtus oeconomus were described. Diagnoses on these taxa were given. A new combination Paranoplocephaloides rauschi comb. n. was designed.

[Parandrya feodorovi gen. n., sp. n.--a new cestode (Cyclophyllidea: Anoplocephalidae) from voles in Siberia]. / Parandrya feodorovi gen. n., sp. n.--novaia tsestoda (Cyclophyllidea: Anoplocephalidae) ot polevok Sibiri.

A new genus and species of the anoplocephalid cestodes, Parandrya feodorovi gen. et sp. n. are described from the Western and Eastern Siberia voles. The new genus Parandrya is distinguished from the genus Andrya Railliet, 1893 by the presence of the cellular form of the uterus. The new genus also differs from other known genera of anoplocephalid cestodes associated with Rodentia, which have a single genital apparatus and cellular uterus, by the transformation of the external receptaculum seminis into the prostatio gland.

[Larvogenesis of the diplocyst of Aploparaksis furcigera (Rud., 1819) Fuhrmann, 1926 (Cestoda, Hymenolepididae)]. / Larvogenez diplotsisty Aploparaksis furcigera (Rud., 1819) Fuhrmann, 1926 (Cestoda, Hymenolepididae)

Data are given on the larvogenesis of the diplocyst of Aploparaksis furcigera. The invagination process of the metamere is described. The external layer of duplicature (exocyst) of the diplocyst has been shown to be a derivate of typical cerecomere. Due to this the larvogenesis of the diplocyst of A. furcigera is regarded as a cystocercoid larvogevesis changed by the adaptation to parasitism in polymyarian intermediate hosts (Oligochaeta). The origin of protective cenogeneses of diplocyst is a response to mechanical effects of the cutaneous-muscular sac of Oligochaeta upon the developing larvocyst.