[S-CG55] Various interactions between solid Earth and climates

[SCG55-P03] The Pliocene-Pleistocene transition had dual effects on North American migratory bird speciation

*Yusuke Yokoyama¹, Shotaro Hirase², Cin-Ty Lee³, Wataru Iwasaki⁴ (1.Atmosphere and Ocean Research Institute, University of Tokyo, 2.Graduate School of Agricultural and Life Sciences, University of Tokyo, 3.Department of Earth, Environmental and Planetary Sciences, 4.Department of Biological Science, Graduate School of Science, Unversity of Tokyo)

Keywords:glacial interglacial cycle, ice sheet, Bioinformatics

Paleo-environmental change is thought to substantially influence biological evolution. In particular, fragmenta- tion of the geographical distributions of vertebrate faunas and subsequent speciation events occurred frequently due to glacial advances after the Pliocene-Pleistocene transition 2.5 million years ago (Ma). However, the effects of glacial advances on speciation between migratory and sedentary birds have not been systematically evaluated. Here, we conducted phylogenetic meta-analysis of 14 closely related pairs of the North American migratory spe- cies and 25 closely related pairs of the North American migratory and neotropical sedentary species and estimat- ed their divergence times using cytochrome b. Whereas divergence events between migratory species were mostly in the Pleistocene (median 1.51 Ma) as previously reported, many divergence events between the migra- tory and sedentary bird species appear to date back to the Pliocene (median 2.77 Ma). These speciation patterns indicate that the Pliocene-Pleistocene transition may have accelerated speciation between migratory bird spe- cies, but did not accelerate that between migratory and sedentary species through counteracting mechanisms.