Variability and Morphological Features of Woolly Rhinoceros Skulls (Coelodonta antiquitatis (Blumenbach 1799)) from Northeastern Asia in the Late Pleistocene

We studied 63 woolly rhinoceros skulls from the northeast of Russia (northwestern Chukotka, northeastern Yakutia) housed in the collection of the Ice Age Museum-Theatre, Moscow. Both sexual dimorphism and size/shape variability of woolly rhinoceros skulls are explored using univariate and multivariate statistics for the first time. Peculiarities of the variability, which are probably related to gender, are expressed in (1) different sets of skull variables the variability of which does not depend on general size variations and (2) differences in skull allometry in males and females. The structure of morphological variability is discussed. Statistically significant morphological heterogeneity is detected within the male and female samples. This is shown to be the consequence of the presence of two size groups that are not related to individual age. Based on published radiocarbon dates, it is hypothesized that there was a decrease in skull size in the woolly rhinoceros is at the end of megainterstadial (MIS) 3 to the early Last Glacial Maximum MIS 2 in northeastern Asia. To test this hypothesis, new radiocarbon dates of the studied specimens are needed.

Automated summary

This study explored sexual dimorphism and size/shape variability of woolly rhinoceros skulls for the first time using univariate and multivariate statistics. The results revealed statistically significant morphological heterogeneity within male and female samples, which may be attributed to the presence of two size groups not related to individual age. New radiocarbon dates of the studied specimens are needed to further test the hypothesis of a decrease in skull size in woolly rhinoceros from MIS 3 to MIS 2 in northeastern Asia.