Diversification of Ramphastinae (Aves, Ramphastidae) prior to the Cretaceous/Tertiary boundary as shown by molecular clock of mtDNA sequences

Genetics and Molecular Biology

Laila Alves Nahum¹  Sérgio Luiz Pereira¹  Flora Maria De Campos Fernandes¹  Sergio Russo Matioli¹  Anita Wajntal¹ 

[1] ,Universidade de São Paulo Instituto de Biociências Departamento de BiologiaSão Paulo SP ,Brazil

关键词: divergence times;    K/T;    mass extinction;    cytochrome b;    12S rDNA;    paleogeography;    phylogeny;   

DOI  :  10.1590/S1415-47572003000400003

来源: SciELO

【 摘 要 】

Partial cytochrome b and 12S rDNA mitochondrial DNA sequences of eight representatives of the Ramphastidae family were analyzed. We applied the linearized tree method to identify sequences evolving at similar rates and estimated the divergence times among some of the taxa analyzed. After excluding Ramphastos tucanus and Capito dayi from our data set, the remaining taxa presented a constant rate of DNA substitution, and branch lengths could be re-estimated with a clock constraint using the maximum likelihood method. Branch lengths were calibrated assuming that Galliformes and Piciformes split around 100 million years ago (mya). Our results indicate that Ramphastinae, and probably Capitoninae, diverged from other Piciformes in the Late Cretaceous (~82 mya), suggesting that Piciformes is another avian order that survived the mass extinction event occurred 65 mya at the Cretaceous/Tertiary (K/T) boundary. The divergence times estimated within the Ramphastinae genera cover the period from the Middle Eocene (around 47 mya) through the Late Miocene (9.5 mya). Our estimate of divergence time is coincidental with the split of the African and the South American continents and other intense geologic activities and modifications of the areas which correspond to the current Neotropics. These events might have influenced the diversification of Ramphastinae in South America.

【 授权许可】

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