Reconstruction of past distribution for the Mongolian toad, Strauchbufo raddei (Anura: Bufonidae) using environmental modeling

The use of ecological models enables determining the current distribution of species, but also their past distribution when matching climatic conditions are available. In specific cases, they can also be used to determine the likelihood of fossils to belong to the same species—under the hypothesis that all individuals of a species have the same ecological requirements. Here, using environmental modeling, we reconstructed the distribution of the Mongolian toad, Strauchbufo raddei, since the Last Glacial Maximum and thus covering the time period between the Late Pleistocene and the Holocene. We found the range of the species to have shifted over time, with the LGM population clustered around the current southern range of the species, before expanding east and north during the Pleistocene, and reaching the current range since the mid-Holocene. Finally, we determined that the ecological conditions during the life-time of the mid-Pleistocene fossils attributed to the species in Europe were too different from the one of the extant species or fossils occurring at the same period in Asia to belong to the same species.