Teeth of early generations of Early Pleistocene elephants (Mammalia, Elephantidae) from Sinyaya Balka/Bogatyri site (Sea of Azov Region, Russia)

Elephants of the mammoth lineage are important for the biostratigraphy of the Early Pleistocene of Eurasia. For Eastern Europe and adjacent regions, a sequence of subspecies has been distinguished, which replaced each other during the Villafranchian. Archidiskodon meridionalis gromovi is the middle Villafranchian phase of these elephants’ evolution and a characteristic member of the Khapry faunal complex of Eastern Europe. This species was described based on a serial collection of teeth from the Khaprovian layers that are outcropping in the Northeast Sea of Azov Region in several sand pits and coastal cross sections (Khapry, Liventsovka, Morskaya 1 and others). The holotype of this species is a nearly complete skull with significantly worn teeth. Therefore, some of its tooth characteristics (lamellar frequency, enamel thickness) have a relatively progressive level and coincides with those of A. m. meridionalis lectotype. This fact led to attempts to replace the taxon A. m. gromovi to others, based on single finds or mixed small samples. The existing objections to the validity of this taxon are mainly related to the underestimation or reassessment of the range of variability of the samples’s characteristics from different localities. It is shown that the lectotype of A. m. meridionalis was chosen not very well, because the lamellar frequency and the enamel thickness of its teeth significantly differ from the average characteristics of the Late Villafranchian sample from the Upper Valdarno. Some authors, recognizing the existence of a primitive form of southern elephants, refer the Middle Villafranchian meridionaloid elephants to Early Villafranchian Mammuthus (=Archidiskodon) rumanus or to the typical Late Villafranchian M. (=A.) meridionalis. Attempts to abandon the use of Gromov’s elephant taxon leads to confusion in the taxonomy of the genus and the inability to use such definitions for biostratigraphic and paleogeographic structures. The work provides a renewed diagnosis of the subspecies A. m. gromovi. The range of variability and the average sampling rates from the Khaprovian layers of the Sea of Azov Region differ from those of the Late Villafranchian A. m. meridionalis from Upper Valdarno. A. m. gromovi is a valid taxon, and is characterized both by cranial and serial dental stratigraphically attached material.

Download Full-text

Revised chronostratigraphy and palaeoenvironmental record of loess-palaeosol sequences in the Azov Sea region of Russia since the late Pleistocene

10.5194/egusphere-egu21-3207 ◽

2021 ◽

Author(s):

Jie Chen

Keyword(s):

Late Pleistocene ◽

Chinese Loess Plateau ◽

Interglacial Period ◽

Sea Of Azov ◽

Last Interglacial ◽

Danube Basin ◽

Climatic Trend ◽

The Sea Of Azov ◽

Azov Sea ◽

Azov Region

Loess-palaeosol sequences are the most intensively studied terrestrial archives used for the reconstruction of late Pleistocene environmental and climatic changes in the Sea of Azov region, southwest Russia. Here we present a revised luminescence-based chronostratigraphy and a multi-proxy record of late Pleistocene environmental dynamics of the most complete and representative loess-palaeosol sequences (Beglitsa and Chumbur-Kosa sections) from the Azov Sea region. We propose a new chronostratigraphy following the Chinese and Danubean loess stratigraphy models that refines the subdivision of the last interglacial palaeosol (S1) in two Azov Sea sites, resolves the uncertainty of the stratigraphic position of the weakly developed paleosol (L1SSm) in Beglitsa section, and allows direct correlation of the Azov Sea sections with those in the Danube Basin and the Chinese Loess Plateau. More importantly, it adds important data to better constrain local and regional chronostratigraphic correlations, and facilitates the interpretation of climatic connections and possible forcing mechanisms responsible for the climatic trend among these regions. In addition, a general succession of environmental dynamics is reconstructed from these two vital sections, which is broadly consistent with other loess records in the Dnieper Lowland and Lower Danube Basin, demonstrating similar climatic trends in these regions at glacial-interglacial time scales. However, differences in details were also identified, especially for palaeosols developed during the last interglacial period, and the cause of these dissimilarities between loess records appears complex.Furthermore, our results have important implications for the chronostratigraphic representativeness of Beglitsa as a key loess section and the reconstruction of the temporal and spatial evolution of late Pleistocene palaeoclimate in the Sea of Azov region.&#160;

Download Full-text