Barcoding large sets of birds allows insights into patterns of evolution, biogeography and speciation

LIJTMAER, DARÍO A.; KERR, KEVIN C. R.

Ciudad de Mexico, Mexico

Congreso; Third International Barcode of Life Conference; 2009

Consortium for the Barcode of Life y Universidad Nacional Autonoma de Mexico

The causes of the highest bird diversity in the Neotropics than in the Nearctic have been a subject of debate. The traditional view was that high tropical diversity is a consequence of high speciation rates, but it has been recently proposed that the reason is the presence of higher extinction rates in temperate regions. Also of interest is the comparison of the processes that generate diversification and structuring in each region. Large sets of barcodes allow studying these continental patterns. We here compare the recently obtained barcodes of 500 bird species from the southern Neotropics (Argentina) with those of North America. This comparison shows that species of both regions have similar average intraspecific divergences in COI (2.4% in Argentina, 2.3% in North America). Average interspecific divergence between closely related species is slightly higher in Argentina (6.2% divergence between nearest congeneric neighbors versus 4.7% in North America). In addition, a lower proportion of closely related species show very low divergence in the southern Neotropics: 8% of nearest congeneric neighbors diverge by less than 1% in Argentina and 20% in North America. Finally, the proportion of species with genetic structure and high intraspecific variation is similar in both regions, but the patterns of geographic structure are more complex in Argentina. Taken together, these results indicate that there are not more young species in the southern Neotropics than in the Nearctic, which suggests that speciation rates are not higher in the former. Instead, species appear to be slightly older in the southern Neotropics.