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Vol 53, No 1 (2019)
- Year: 2019
- Articles: 10
- URL: https://journals.rcsi.science/0031-0301/issue/view/10274
Article
On New Approaches in the Study of Evolution of Macrotaxa and the Concept of Econ
Abstract
The modern attention to global and system approaches to the study of life evolution increase the interest in integrating macroevolutionary and ecological research and developing their theoretical foundations. The econ of species is suggested as an elementary fundamental unit of evolving paleobiospheric spatiotemporal continuum. The concept of econ, the unity of species and its ecological niche, allows solving issues of evolution of biodiversity, evolutionary macroecology and biogeography on spatiotemporal scales and in the framework of the system macrotaxon–biosphere. These studies need to be based on actual taxa. Therefore, a natural classification of organisms, reflecting true phylogeny, is of particular relevance. A holistic approach will allow obtaining more substantiated conclusions on the evolution and distribution of both fossil and modern organisms.
1-9
Distribution Patterns and Morphology of Islandiella norcrossi (Cushman) in the Upper Quaternary Deposits of the Laptev Sea
Abstract
The ecology and taxonomy of Islandiella norcrossi (Cushman, 1933), a typical representative of the Arctic calcareous benthic foraminifers, are analyzed based on microfossils from the Late Pleistocene-Holocene deposits of the Laptev Sea. This species is distributed on the shelf and continental slope of the Arctic seas, and indicates normal marine conditions with a seasonal ice cover and cold Arctic water masses. The species is also associated with a high seasonal productivity in sea-ice marginal zone. Tests are abundant in the Laptev Sea sediments, and show some variability in the size and shape of chambers, which was possibly caused by harsh environmental conditions of the Arctic (limited period of growth and reproduction); aberrant forms with an additional aperture being also present. The population contains tests of macrospherical and microspherical generations, as well as juveniles.
10-19
On the Taxonomic Composition of Mollusks from the Tavda Formation of Western Siberia
Abstract
The taxonomic composition of bivalves and gastropods from the clays of the Tavda Formation was studied from the Kyshtyrla Quarry, 23 km south of the city of Tyumen and from the drill core of Boreholes 8 and 11 south of the city of Omsk. The Kyshtyrla malacofauna is represented by siderite molds and imprints, rarely entire shells, sometimes bivalved specimens, among which 19 taxa were identified. The borehole material contained eight species of eight genera. These assemblages show striking resemblance to the Chegan Fauna of North Ustyurt, Aral and Turgay, suggesting their similar age and direct paleogeographic connections between these basins. Both assemblages indicate marine, probably slightly brackish-water environments and relatively shallow-water deposition below the surf zone in conditions varying from normal aeration (favorable for benthic organisms) to dysoxic.
20-29
Shell Microstructure of Strophomenide Bilobia Cooper (Brachiopoda) from the Late Ordovician of Baltoscandia
Abstract
The shell microstructure of two species of Bilobia, B. musca (Öpik, 1930) and B. alichovae Madison, 2017 (family Leptestiidae Öpik, 1933) from the Late Ordovician of Baltoscandia was studied. Possible primary layer, fibers, pseudopunctae, extropunctae, and the only known for strophomenides hollow punctae are described. Possible diagenetic changes of different skeletal elements in different parts of the shell are appreciated. The assumption of A. Öpik (1933) on the presence of hollow punctae in B. musca is confirmed.
30-43
Bryozoans and Brachiopods from the Famennian (Upper Devonian) of the Central Russian Platform
Abstract
In Lipetsk and Orel oblasts the sediments of the Zadonsk Regional horizon (Lower Famennian, Upper Devonian) have yielded two species of trepostome bryozoans (Leptotrypa lipovkiensis sp. nov. and Anomalotoechus promiscuus Lavrentjeva, 1974) and brachiopods belonging to the five orders that dominate the benthic association of this horizon. These bryozoans are characterized by high variability in colony growth habits and internal structures. Representatives of both invertebrate groups obviously developed under periodically changing conditions of the inner part of a shallow shelf.
44-51
New Species of Mischopterida = Megasecoptera (Insecta) from the Permian Deposits of the Vorkuta Basin
Abstract
A new genus and two new species Taigahymen borealis gen. et sp. nov. from the family Bardohymenidae and Cyclocelis devexa sp. nov. from the family Sphecopteridae are described from the Permian insect-bearing deposits of the Vorkuta basin. No representatives of the order Mischopterida have been previously recorded from the Vorkuta basin. The both new species are the latest and northernmost species of their families. These species, similar to those from the Carboniferous and Lower Permian deposits, do not contradict the Ufimian age of the Vorkuta Group.
52-55
A New Species of the Genus Homocloeus Jordan (Coleoptera: Anthribidae) in Miocene Mexican Amber
Abstract
A new species, Homocloeuspopovi sp. nov., is described from Miocene Mexican amber. The new species is similar to H. puncticollis but differs in having the rostrum without a middle carina, and in the transverse carina more curved to the base of the elytra, flattened elytral interstriae, and interstria 5 with a tubercle in the apical quarter. This is the first record of the genus Homocloeus as a fossil.
56-61
Paleogene Turtles of Crimea
Abstract
This paper describes remains of fossil turtles from five Paleogene localities of Crimea. Two are Danian (Ak-Kaya 2 and Sakharnaya Golovka) and three are Bartonian (Ak-Kaya 1, Bakhchisarai and Prolom). The best studied turtle fauna comes from the Ak-Kaya 1 locality and includes three taxa: marine Argillochelys sp. (Cheloniidae) and Cosmochelys sp. (Dermochelyidae), and an unidentified soft-shelled turtle (Trionychidae indet.). Argillochelys sp. shows similarities with Argillochelys antiqua (König, 1825) from the Eocene of Europe. The new data expands our knowledge of intraspecific variability and the distribution of turtles of the genera Argillochelys and Cosmochelys. Unidentified cheloniids (Bakhchisarai, Prolom, and Sakharnaya Golovka), dermochelyids (Bakhchisarai and Prolom) and trionychids (Ak-Kaya 2 and Prolom) are described from other Paleogene localities of Crimea.
62-73
Lizards of the Families Eoxantidae, Ardeosauridae, Globauridae, and Paramacellodidae (Scincomorpha) from the Aptian–Albian of Mongolia
Abstract
Classification of lizards of the infraorder Scincomorpha is discussed in the paper. The history and problems of studying Eoxantidae, Ardeosauridae, Globauridae, and Paramacellodidae fossil families from this infraorder are presented in more detail. New species from the Aptian–Albian deposits of Mongolia have been added to the lizard families listed above.
74-88
Xenoxylon (Coniferales) Fossil Woods from the Jurassic and Cretaceous Deposits of Siberia and the Russian Far East
Abstract
Xenoxylon fossil wood species (X. latiporosum, X. phyllocladoides, X. japonicum, X. meisteri, and X. nariwaense) from the Cretaceous localities of Siberia and the Russian Far East are described based on anatomical wood features. X. japonicum and X. nariwaense have not been recorded in Russia, and X. meisteri has not been recorded in the Russian Far East. The knowledge about the stratigraphic distribution of X. japonicum and X. nariwaense, which were earlier described only from the Upper Triassic deposits, is improved. A complete list of revised Xenoxylon fossil woods from the Jurassic and Cretaceous deposits of Siberia and the Russian Far East is provided.
89-104