Nº 5 (2023)

Representatives of the genus Oscillopha Malchus, 1990 from the Aptian, Albian and Cenomanian of the southwestern spurs of the Gissar Ridge (southeastern Turkmenistan) are revised. Questions of taxonomy of Mesozoic Lopha-like oysters are discussed. The diagnoses and composition of the family Arctostreidae Vialov, 1983, the subfamily Arctostreinae Vialov, 1983 and the genus Oscillopha Malchus, 1990 are specified. In the Aptian and Albian, the genus Oscillopha is represented by the species O. eos (Coquand, 1869) and in the Cenomanian—by the species O. dichotoma (Bayle, 1849).

Reconstructions of the cross sections of two specimens of the type species of Neouddenites, N. andrianovi Ruzhencev from the Kungurian of Western Verkhoyanie revealed features of its ontogenetic development. The species is characterized by slow extension of the medial spiral, which only stops at the last whorl. The shell shape continuously changes from very wide at the first whorl to very narrow at the last whorl. The umbilicus at the beginning of ontogeny expands slightly, making the shell evolute. The umbilicus then strongly narrows, and at the last whorls the shell acquires a completely involute shape. Significant changes in the shape of the whorl cross section are observed throughout ontogeny allowing recognition of four successive stages, designated as “Eocanites”, “Pronorites”, “Prouddenites”, and “Neouddenites”. Neouddenites andrianovi was found to lack lateral grooves and ventrolateral ridges, previously considered to be diagnostic characters of the genus Neouddenites.

From the Jurassic of Asia, new representatives of the caddisfly order from the families Necrotauliidae and Philopotamidae are described. From the Upper Jurassic (Karabastau Formation) locality of Karatau in South Kazakhstan, Karataulius martae sp. nov., Archiphilopotamus expectatus sp. nov. and Juraphilopotamus inopinatus sp. nov., while from the Middle Jurassic (Itat Formation) locality Kubekovo, Krasnoyarsk Territory, Necrotaulius communis sp. nov. and Juraphilopotamus similis sp. nov. are described. Keys for species of the genera Archiphilopotamus Sukatsheva, 1985 and Juraphilopotamus Wang, Zhao et Ren, 2009 are given. Data on the stratigraphic and geographical distribution of the Mesozoic representatives of the Philopotamidae are given.

The genera Palaeoalatorostrum Rheinheimer, 2007 and Cryptorrhynchites Haupt, 1950 are transferred from the tribe Otiorhynchini of the subfamily Entiminae (Curculionidae) and from the tribe Cryptorhynchini of the subfamily Molytinae (Curculionidae), respectively, to the tribe Attelabini of the subfamily Attelabinae of the family Attelabidae; genera Palaeocrassirhinus Rheinheimer, 2007 and Palaeocneorhinus Rheinheimer, 2007 are transferred from the tribes Anypotactini and Cneorhinini, respectively, to the tribe Brachyderini. A key to the species of the genus Palaeocrassirhinus is given.

Remains of small ducks are described from the boundary early–middle Miocene deposits of Tagay (Baikal area), the only locality in Asia with a representative bird fauna of the Miocene climatic optimum. New taxa Mioquerquedula palaeotagaica sp. nov. and Tagayanetta palaeobaikalensis gen. et sp. nov., corresponding in size to modern Anas crecca, as well as an even smaller duck Selenonetta lacustrina gen. et sp. nov. are described. A revision of the genus Mioquerquedula is undertaken; “Anas” integra Miller, 1944 from the Lower Miocene of North America is here transferred to this genus. Tagayanetta gen. nov. is here considered as an evolutionarily more advanced genus than Mioquerquedula, probably close to Anatini. Selenonetta gen. nov. is considered as a taxon close to the divergence between Mergini and other Anatinae. A similar form (possibly the same species) is present in the Sansan locality (France).

With the help of an electron microscope, the remains of microorganisms and biogenic ultramicrostructures were identified in the black oncolites of the Kalancha Formation and the rocks containing them. As a result of the research it was revealed that only in oncoliths as opposed to containing rocks are other remnants of microorganisms widely distributed: recrystallized filamentous cyanobacteria, fossilized colonies of tubular organisms, as well as individual coccoid formations of biogenic origin. Based on the new factual material, the features of the vital activity of organisms and their participation in the construction of the concentric structure of black oncoliths are analyzed, the features of the interaction of biogenic and abiogenic factors are established.