Extinction vs. Rapid Radiation: The Juxtaposed Evolutionary Histories of Coelotine Spiders Support the Eocene–Oligocene Orogenesis of the Tibetan Plateau

We use phylogenetics, molecular dating, ancestral area reconstructions, diversity, and ecological niche analyses to investigate the spatiotemporal evolution of 286 coelotine species from throughout the region.

 ZHE ZHAO1,2 AND SHUQIANG LI1,3∗

1 Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China;
2 Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Yezin, Nay Pyi Taw 05282, Myanmar;
3 University of Chinese Academy of Sciences, Beijing 100049, China;
∗ Correspondence to be sent to: Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; E-mail: lisq@ioz.ac.cn
   Received 20 January 2016; reviews returned 24 March 2017; accepted 24 March 2017
   Associate Editor: Michael Charleston
 
PubYear : 2017
Volume :  0(0)
Publication Name: Systematic Biology 
Page number : 1-19
 
Abstract: Evolutionary biology has long been concerned with how changing environments affect and drive the spatiotemporal development of organisms. Coelotine spiders (Agelenidae: Coelotinae) are common species in the temperate and subtropical areas of the Northern Hemisphere. Their long evolutionary history and the extremely imbalanced distribution of species richness suggest that Eurasian environments, especially since the Cenozoic, are the drivers of their diversification.We use phylogenetics, molecular dating, ancestral area reconstructions, diversity, and ecological niche analyses to investigate the spatiotemporal evolution of 286 coelotine species from throughout the region. Based on eight genes (6.5 kb) and 2323 de novo DNA sequences, analyses suggest an Eocene South China origin for them. Most extant, widespread species belong to the southern (SCG) or northern (NCG) clades. The origin of coelotine spiders appears to associate with either the Paleocene–Eocene Thermal Maximum or the hot period in early Eocene. Tibetan uplifting events influenced the current diversity patterns of coelotines. The origin of SCG lies outside of the Tibetan Plateau. Uplifting in the southeastern area of the plateau blocked dispersal since the Late Eocene. Continuous orogenesis appears to have created localized vicariant events, which drove rapid radiation in SCG.North-central Tibet is the likely location of origin for NCG and many lineages likely experienced extinction owing to uplifting since early Oligocene. Their evolutionary histories correspond with recent geological evidence that high-elevation orographical features existed in the Tibetan region as early as 40–35 Ma. Our discoveries may be the first empirical evidence that links the evolution of organisms to the Eocene–Oligocene uplifting of the Tibetan Plateau.
Keyword: Tibet; biogeography; ecology; molecular clock; diversification