Discovery of the skull ofStephanorhinus kirchbergensis(Jäger, 1839) above the Arctic Circle

Abstract

AbstractThe skull of the extinct rhinocerosStephanorhinus kirchbergensis(Jäger, 1839) was discovered in the Chondon River valley (Arctic Yakutia, Russia) during the summer of 2014. This is the first find ofStephanorhinusabove the Arctic Circle, expanding significantly the known geographic range of the genus.14C dating and geologic evidence indicate that the skull dates to between 48,000 and 70,000 yr, corresponding to Marine Oxygen Isotope Stage 4/3. It is thus among the latest records of this species. To explore the evolutionary and natural history of this relatively unknown animal, we performed morphological, dietary, and genetic analyses. Phylogenetic inference based on a complete mitochondrial genome sequence confirms the systematic placement ofStephanorhinusas most closely related to the extinct woolly rhinoceros,Coelodonta. Food remains in the fossas of the cheek teeth, identified asLarix,Vaccinium,Betulasp.,Aulacomnium, and dicotyledonous herbs and grasses, suggest a mixed feeder’s diet. Microwear analysis suggests that, during the last months of its life, this individual fed predominantly on leaves and twigs. The habitat ofStephanorhinuscomprised grassland and open woodland that were characterized by moist and cold climate conditions, similar to those in the region today.