Detailed biostratigraphic scales as based on the palaeobiogenetical approach (an example of the Upper Bajocian – Lower Bathonian ostracod scale of the Russian Platform)

Two new species of ostracods of the family Progonocytheridae Sylvester-Bradley Camptocythere (C.) lateres Tesakova et Shurupova, sp. nov. and C. (C.) angustius Tesakova et Shurupova, sp. nov. from the Michalskii and Besnosovi ammonite zones (Upper Bajocian – Lower Bathonian, Middle Jurassic) of the Sokur section (Saratov) are described. The changes in ontogenesis in the phylogeny of Camptocythere (C.) lateres Tesakova et Shurupova in the stratigraphical interval corresponding to the Palaeocytheridea kalandadzei ostracod Zone, and especially to the beds with C. (C.) lateres, have been studied. The levels of the change in the predominant type of sculpture (corresponding to evolutionary boundaries) are recognized in the sculpture development among the adult representatives of the species in its phylogeny. This palaeobiogenetic (heterochrony) approach allows subdivision of the beds with C. (C.) lateres into three stratigrapical intervals characterized by changes in the type of sculpture

The Potential of Petromagnetic Methods in Paleoecological Reconstructions Based on the Example of Jurassic Deposits (Callovian–Lower Oxfordian) of the Mikhailovtsement Section (Ryazan Region)

© 2019, Allerton Press, Inc. Abstract—: Based on a detailed integrated petromagnetic, lithological, and micropaleontological study of the Mikhailovtsement reference section of the Moscow syneclise (Ryazan Region), the fluctuations in the Middle Russian Sea level in the Callovian–Early Oxfordian were reconstructed. According to the variations of petromagnetic parameters through the section, seven petromagnetic intervals corresponding to different stages of the paleobasin evolution were established. These stages are correlated with sea level fluctuations established on the basis of changes in the rock lithology and the ostracod complexes. In general, the character of sea level change in the Callovian–Oxfordian that was revealed during the study of the Mikhailovtsement section is in agreement with the global trends

TAXONOMIC REVISION OF LIVENTAL’S SPECIES OF BRACKISH WATER OSTRACODA (Crustacea) AND DESIGNATION OF NEOTYPES

The aim of this paper is to re-describe LIVENTAL’s (1929) species through the SEM pictures of the specimens included in various historical collections deposited at the Micropaleontological Laboratory of the VNIGRI, St. Petersburg, Russia, since the original Livental’s collection seems to be lost as well as the Azerbaijan collections by Agalarova (AGALAROVA, 1956, 1967; AGALAROVA et al., 1940, 1961). In particular, the revision is based on the VNIGRI collection AZNII27 of L.N. Klein who studied the ostracods of the Azerbaijan area of Babazanan (KLEIN, 1960, the same area studied by LIVENTAL, 1929) and on several other collections from Turkmenistan, the Caucasus and Euxinic/Black Sea? Basin included both in historical collections (Mandelstam, Luebimova, Rozjeva, Stepanaitys) as well as on new findings from the Euxinic Basin. The discussion on each species is accompanied by its synonymy, and an updated geographical and stratigraphical distribution based on the new chronostratigraphical data of KRIJGSMAN et al. (2010) and VAN BAAK et al. (2013). In those few cases where the Livental’s species are still living in the Caspian or Black Sea, the soft parts are described and the ecological parameters given

Integrated stratigraphy of the reference sections for the Callovian-Oxfordian boundary in European Russia

The most complete succession of the Callovian-Oxfordian boundary recorded in European Russia is the Dubki section, where the authors have carried out integrated paleontological and magnetostratigraphical studies. A continuous sequence of the West-European biostratigraphic units in the interval from the Lamberti to the Cordatum Zones is present in this section, and 10 ammonite biohorizons have been recognized. Additional data concerning nannofossil assemblages, foraminifers, ostracods, belemnoids and the paleomagnetic polarity for the Dubki section are also presented. The Callovian-Oxfordian boundary, marked by FAD of the genus Cardioceras, is placed at the base of the scarburgense biohorizon. The paleontological richness and continuity of the succession make the Dubki section a possible GSSP candidate for the Callovian/Oxfordian boundary. Correlation of the Dubki ammonite succession with those of the other GSSP candidates, Redcliff Point and Thuoux, is proposed. Other sections studied in Russia have yielded some additional observations on the Callovian-Oxfordian boundary beds. Although in the Dubki section the praemartini biohorizon is not found, its existence is proved, however, in Orenburg region (Khanskaya Gora). In the Datchovskaya section (Northern Caucasus) the paucicostatum biohorizon is characterized by an unusual combination of Subtethyan and Boreal ammonites, including Kosmoceras, which is not typical of the paucicostatum biohorizon outside the Northern Caucasus