V. Y. Biserkov

Polystoma macrocnemis n. sp. (Monogenea: Polystomatidae) from the Iranian longlegged wood frog Rana macrocnemis (Ranidae) in Turkey

Polystoma macrocnemis n. sp. (Polystomatidae) is described from the urinary bladder of Rana macrocnemis (Ranidae) in Turkey. Its general morphology is similar to that of other members of the genus, but it is distinguished from closely related species by numerical parameters of the hamuli and also by its host species and geographical range.

Development of the plerocercoid I of Ophiotaenia europaea in reptiles

The existence of a two-host life-cycle in ophiotaeniid proteocephalideans was tested experimentally using Ophiotaenia europaea as a model. Three species of reptiles, Natrix natrix, Natrix tessellata and Lacerta viridis, were fed with experimentally infected copepods containing a large number of infective plerocercoids I. A few plerocercoids, most of which were dead, corresponding morphologically to the plerocercoid II developmental stage of O. europaea, were found encysted in the intestinal wall of N. natrix (8 days p.i.), N. tessellata (5 and 150 days p.i.) and L. viridis (40 days p.i.), while no plerocercoids or adult worms were recovered from their intestines. The results indicate that the infective plerocercoid I of O. europaea cannot undergo further development when ingested directly by the final host (a reptile), and that environmental temperature stimuli cannot initiate a reverse plerocercoid migration to the gut followed by strobilization.

Heligmosomoides glareoli Baylis, 1928 (Nematoda: Heligmosomidae): redescription and synonymy

Paratypes of Heligmosomoides glareoli Baylis, 1928 are re-described. Specimens of the same species from Microtus nivalis and Clethrionomys glareolus collected in Bulgaria were also studied. H. tatricus (Erhardova, 1955) Durette-Desset, 1967 is considered a synonym of H. glareoli on the basis of the morphometric characters, synlophe structure and the distribution of their host.

Polystoma fuscus n. sp. (Polystomatidae) from the common spadefoot Pelobates fuscus (Pelobatidae) in Bulgaria

Polystoma fuscus n. sp. (Polystomatidae, Polystomatinae) is described from the urinary bladder of Pelobates fuscus (Pelobatidae) in Bulgaria. Its general morphology is similar to that of other members of the genus but distinguished from them by the underdeveloped hamuli similar to the larval hamular primordia. The new species is also differentiated from the members of the genera of the subfamily Polystomatinae described without hamuli.

A ‘mini-microtome’ for preparing serial sections directly on a light microscope stage

A simple ‘mini‐microtome’ is described which can be attached to a standard compound microscope. The device enables small biological specimens, such as parasitic helminths, to be sectioned with precise orientation.

Spalacina yanchevi n. g., n. sp. (Nematoda: Heligmonellidae) from the lesser mole rat Spalax leucodon (Rodentia: Spalacidae)

Spalacina n. g. (Heligmonellidae, Nippostrongylinae) is erected for S. yanchevi n. sp. (type-species) [syns Heligmonina nevoi of Genov & Janchev (1982) and Genov (1984)] from Spalax leucodon (Spalacidae) and two other species from spalacid rodents previously considered as members of Heligmonina Baylis, 1928: S. spalacis (Sharpilo, 1973) n. comb. and S. nevoi (Wertheim & Durette-Desset, 1975) n. comb. The new genus belongs to the subfamily Nippostrongylinae and is closely related to the genus Heligmonina from which it can be distinguished by a greater angle of rotation of the synlophe, the absence of a gradient on the ventral ridges and a weakly developed right dorsal ridge. The zoogeographical distribution of Spalacina spp. is associated with that of Palaearctic spalacids. S. yanchevi differs from S. spalacis and S. nevoi in the number and size of the ridges, the distance between the extremities of the rays 6 and 8, the degree of reduction of the dorsal ray and the length of the spicules.