The emergence of modern zoogeographic regions in Asia examined through climate-dental trait association patterns

Abstract

The complex and contrasted distribution of terrestrial biota in Asia has been linked to active tectonics and dramatic climatic changes during the Neogene. However, the timings of the emergence of these distributional patterns and the underlying climatic and tectonic mechanisms remain disputed. Here, we apply a computational data analysis technique, called redescription mining, to track these spatiotemporal phenomena by studying the associations between the prevailing herbivore dental traits of mammalian communities and climatic conditions during the Neogene. Our results indicate that the modern latitudinal zoogeographic division emerged after the Middle Miocene climatic transition, and that the modern monsoonal zoogeographic pattern emerged during the late Late Miocene. Furthermore, the presence of a montane forest biodiversity hotspot in the Hengduan Mountains alongside Alpine fauna on the Tibetan Plateau suggests that the modern distribution patterns may have already existed since the Pliocene.

Fig. 1. Redescriptions rA–rI in the present-day dataset.

Localities that satisfy both queries, only the dental traits query, only the climate query, and neither query, are drawn in purple, red, blue, and gray, respectively. For each redescription, we list the query over dental traits variables (q_D), the query over bioclimatic variables (q_C), the accuracy (J) as well as the size of its support as a percentage of the total number of localities (supp%). See maps visualization in ref. .

Fig. 2. Focus maps of redescriptions rB and rC (columns) evaluated on fossil localities from the different time intervals, considering the corresponding paleoclimate model simulation (rows).

a rB in the Early Miocene; b rB in the Middle Miocene; c rB in the early Late Miocene; d rB in the late Late Miocene; e rB in the Pliocene; f rC in the Early Miocene; g rC in the Middle Miocene; h rC in the early Late Miocene; i rC in the late Late Miocene; j rC in the Pliocene. Fossil localities that support both queries, only the dental traits query, only the climate query and neither queries, are drawn in purple, red, blue, and gray, respectively. Present-day localities are drawn in the background, for reference. See maps visualization in ref. .

Fig. 3. Temperature, precipitation, elevation, bunodonty, and hypsodonty trends through the Neogene.

a Global temperature trend (based on ref. ), along with bunodonty and mean annual temperature average values in northern and southern Asia. b Modeled mean annual precipitation for East Asia (based on ref. ), along with hypsodonty and annual precipitation average values in northwestern (NW) and southeastern (SE) China. Average values and standard deviations (represented as error bars) are calculated over the localities in each group, which number (n) 18, 37, 23, 51, and 15 in northern Asia, 3, 8, 7, 5, and 4 in southern Asia, 6, 29, 14, 33, and 11 in NW China, 7, 8, 7, 20, and 6 in SE China, respectively for the five-time intervals. c Elevation estimates for the Tibetan Plateau (data resources in Supplementary Table 1).