The wood lemming and the development of taiga in Late Pleistocene Central Europe

Taxonomic identification remains a challenge for fossil small mammals, in particular in the case of morphologically close species. These identifications are especially essential in the case of species with different ecological tolerances for paleoenvironmental and paleoclimatic inferences. Among rodents which depend on peculiar environments, the wood lemming (Myopus schisticolor) only inhabits boreal forests and is a bryophage specialist burrowing under specific moss covers. In the fossil record, its identification has long been problematic and Myopus has often been mixed up with the tundra lemming (Lemmus sp.), a rodent inhabiting the arctic open landscape. By applying geometric morphometrics on fossil Lemmini specimens from Late Pleistocene Central Europe, this paper demonstrates the occurrence of Myopus at least during Marine Isotopic Stage 3 and Last Glacial Maximum in the region. Its presence has a strong impact on paleoclimatic and paleoenvironmental reconstructions as demonstrated by the application of the Bioclimatic analysis method suggesting a colder climate as well as the identification of a taiga biozone that remained undetected if this species is not included. This work definitively attests the essential contribution of geometric morphometric analyses to a better understanding of small mammal communities.