Vol 52, No 1 (2018)

Rasnitsynites tarsalis Kasparyan (Ichneumonidae, Townesitinae) described from the Baltic amber is recorded for the first time in the Rovno amber (Gulyanka, Zhitomir Region); therefore, this is the southernmost and easternmost find of Townesitinae. The presence of numerous extinct taxa of Townesitinae and tribes of Hybrizoninae Blanchard 1845 = Paxylommatinae Förster, 1862 = Hybrizontinae Marshall, 1872 confirms close relation of the Bembridge Marls fauna (Upper Eocene of England) and that of the succinites (Baltic, Rovno, and other Late Eocene European ambers); they are common in the succinites and in the Bembridge Marls and are only known from these localities.

Two conodont species, Mesotaxis falsiovalis Ziegler et Bultynck, 1989 and Mesotaxis guanwushanensis (Tian, 1988), are considered. It is concluded that they clear differ from each other and, hence, both are valid. The position of these species in the lineage of phylomorphogenetic development of the genus Mesotaxis.

An incomplete skeleton of the ichthyosaur Ophthalmosaurus icenicus Seeley, 1874 excavated in the Oxfordian–Kimmeridgian beds south of the town of Syzran (Samara Region) is described. Members of the genus Ophthalmosaurus are characterized by a unique combination of characters, most of which are well-pronounced in the specimen described here: the extracondylar area of the basioccipital is reduced, but still visible beyond the occipital condyle and has a well-pronounced ventral notch; the scapular shaft is mediolaterelly flattened; the humerus has three distal facets: the anterior facet is the smallest; the facet for the accessory preaxial element has a sharpened anterior margin; the facet for the radius faces distally; the facet for the ulna faces posterodistally; the posterior margin of the ulna is concave and sharpened, involved in the perichondral ossification; the intermedium is rhomboid, with two distal facets equal in size for the second and third distal carpals; the epipodial and autopodial elements are round and thickened, loosely arranged in the fin. This specimen is the first reliable evidence of the presence of Ophthalmosaurus in the Oxfordian–Kimmeridgian of Russia. The previously described remains of a Kimmeridgian ichthyosaur referred to as O. undorensis Efimov, 1991 should be identified as Ophthalmosauridae indet.

Mammal population of the northwestern Altai included residents, autochthonous species, cosmopolitans, and migrants. The last clearly indicate biogeographical relationships of the biota of the Altai Mountains in the Pleistocene. Most of them penetrated into the Altai from the south. The majority of ungulates and rodents migrated from Central Asia. Yak, red dog, and snow leopard came from the Himalayas, Pamir, and Tien Shan. The natural environment of the Altai Mountains in the Pleistocene enabled migrations of these mammals from the south to north. The same opportunity was true of the ancient man. It is possible to assume that humans migrated from southeastern Asia and Indochina along the eastern foothills of the Himalayas and Nan Shan Mountains to the northwest, to the Zaisan Depression and Altai. This resulted in inevitable exchange of gene material of Paleolithic human populations of southeastern Asia and the Altai.

Middle Permian Inoceramus-like bivalves of the genera Kolymia Licharew and Cyrtokolymia Astafieva endemic to the East Boreal Biogeographic Realm are considered. Cyrtokolymia, previously regarded by the author as endemics of the Verkhoyansk–Okhotsk Province and including only the type species, are also recorded in the Kolyma–Omolon Province, where they are represented by the endemic species C. bobini sp. nov. An emended diagnosis of the genus Cyrtokolymia is provided. The genus Kolymia comprises about 30 species. The greatest diversity of Kolymia (24 species, 13 of which are endemic) is known from the Verkhoyansk–Okhotsk Province, which is the center of diversification of this genus. The Kolyma–Omolon Province is characterized by 12 species, only three of which are endemic. In other provinces of the East Boreal Realm, only individual members of Kolymia are known. From the Middle Permian of the Omolon Massif, northern Verkhoyansk Region, and Penzhinsky Ridge, the following new species are described: Kolymia posneri Muromzeva, Kusnezov et Biakov, sp. nov., K. pontoneica Biakov, sp. nov., K. simkiniformis Biakov, sp. nov., and Cyrtokolymia bobini Biakov, sp. nov.

The ammonoid family Sirenitidae from the Upper Carnian yakutensis Zone of northern Middle Siberia and Northeastern Asia is revised. A new genus Orientosirenites gen. nov. with the type species O. bytschkovi sp. nov. is established based on the study of the main morphological characters of the shell. The new genus and the species O. bytschkovi are described and the species O. yakutensis (Kiparisova) is redescribed. The new data allow the taxonomic composition and the distribution of the Carnian ammonoids of the Boreal Realm to be updated.