Juvenile remains of the “woolly rhinoceros” Coelodonta antiquitatis (Blumenbach 1799) (Mammalia, Rhinocerotidae) from the Tomsk Priob'e area (southeast Western Siberia)

Ontogenetic studies based on fossil mammals are rather scarce, including for the “woolly rhinoceros” Coelodonta antiquitatis (Blumenbach 1799). In this paper, for the first time, the earliest age stages (from 6 months to 3.5 years) of C. antiquitatis have been studied on the basis of several lower jaw fragments and limb bones from two Late Pleistocene sites along the Ob' (at Krasny Yar and near Kargasok) in the Tomsk Priob'e area (Tomsk region, southeast Western Siberia). As opposed to other mammalian species (e.g. mammoths), the absence of great concentrations of C. antiquitatis juvenile remains (possibly due to the palaeoecological features of this taxon) has to be emphasized. Finds of skulls, jaws, and isolated milk molars are very rare, particularly in those cases of individuals younger than three years. Therefore, the remains from Krasny Yar, belonging to individuals characterized by different ages, represent a unique case.A large series of osteological material on the mandibles with functioning milk teeth and forming permanent teeth, belonging to calves from 6 months to 3.5 years of age, is described. For the first time, a large series of C. antiquitatis tubular bones of different individual ages (from birth to adulthood) is described, and the order and age of epiphysis adhering is revealed. The proportions of tubular bones (ratio between epiphysis and diaphysis) remain the same in stages 3–5 of individual progress (over 3 years of age). An assumption about C. antiquitatis sizes in different ontogenetic stages and the rate of growth is made. The body size for one-month-old calves is approximately 72 cm in shoulder height and about 120 cm in length. Well-known ontogenetic studies concerning modern African rhinoceroses (Diceros bicornis L. 1756 and Ceratotherium simum simum [Burchell, 1817]) as well as other ontogenetic studies performed on C. antiquitatis juvenile dental material have also been taken into consideration in this paper.