Problems in Estimating Divergence Times
Description: Palaeognathae including ostiches, emus, rheas and tinamous is believed to have originated in Gondwana-derived continents. We recovered nuclear genome fragments as well as mitochondrial genomes from extinct elephant birds of Madagascar, and reconstructed a robust phylogenomic time-tree for Palaeognathae. In contrast to the prevailing theories, our tree based on morphological characters free from convergence placed the fossil paleognths from the Northern Hemisphere as the basal lineage. Such molecular and morphological evidence strongly suggests the Northern Hemisphere origin of Palaeognathae. They were probably flying birds, as estimated by the mitochondrial substitution rate, and migrated to the Southern Hemisphere and explosively speciated around the Cretaceous-Paleogene boundary. They then extended their distribution to the Gondwana-derived landmasses by the overseas dispersal, and gigantism subsequently occurred independently on each landmass.
Amount: ¥4,940,000
Funding type: research
Funder scheme: Grant-in-Aid for Scientific Research (C)
Start date: 2013-04-01
End date: 2016-03-31
Investigator: Masami Hasegawa
Institution: The Institute of Statistical Mathematics
Subfield: Paleontology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Funded outputs count: 8
Funder award ID: 25440219
OpenAlex ID: G4331982147