Birds are among the most diverse and intensively studied vertebrate groups, but many aspects of their higher-level phylogeny and evolution still remain controversial. One contentious issue concerns the antiquity of modern birds (=crown Aves): the age of the most recent common ancestor of all living birds (Gauthier 1986). Very few Mesozoic fossils are attributable to modern birds (e.g., Clarke et al. 2005; Dyke and Kaiser 2011; Brocklehurst et al. 2012; Ksepka and Boyd 2012) suggesting that they diversified largely or entirely in the early Paleogene, perhaps in the ecological vacuum created by the extinction of non-avian dinosaurs, pterosaurs, and many archaic (stem) birds (e.g., Longrich et al. 2011). In contrast, molecular studies indicate that modern birds commenced radiating deep within the Mesozoic, for example ∼130 Ma (Cooper and Penny 1997; Haddrath and Baker 2012) or ∼113 Ma (Jetz et al. 2012), with ratites, galliforms, anseriforms, shorebirds, and even passerines surviving across the KPg boundary (∼66 Ma). The oldest molecular dates further imply an extraordinarily rapid early bird evolution, with the modern birds appearing only 20 myr after Archaeopteryx (∼150 Ma). However, both approaches entail considerable uncertainties: for example, nonpreservation of fossils always underestimates the antiquity of lineages, whereas rate heterogeneity, saturation, and calibration uncertainty can strongly bias molecular divergence dating.

Morphological Clocks in Paleontology, and a Mid-Cretaceous Origin of Crown Aves

CAU, ANDREA;
2014

Abstract

Birds are among the most diverse and intensively studied vertebrate groups, but many aspects of their higher-level phylogeny and evolution still remain controversial. One contentious issue concerns the antiquity of modern birds (=crown Aves): the age of the most recent common ancestor of all living birds (Gauthier 1986). Very few Mesozoic fossils are attributable to modern birds (e.g., Clarke et al. 2005; Dyke and Kaiser 2011; Brocklehurst et al. 2012; Ksepka and Boyd 2012) suggesting that they diversified largely or entirely in the early Paleogene, perhaps in the ecological vacuum created by the extinction of non-avian dinosaurs, pterosaurs, and many archaic (stem) birds (e.g., Longrich et al. 2011). In contrast, molecular studies indicate that modern birds commenced radiating deep within the Mesozoic, for example ∼130 Ma (Cooper and Penny 1997; Haddrath and Baker 2012) or ∼113 Ma (Jetz et al. 2012), with ratites, galliforms, anseriforms, shorebirds, and even passerines surviving across the KPg boundary (∼66 Ma). The oldest molecular dates further imply an extraordinarily rapid early bird evolution, with the modern birds appearing only 20 myr after Archaeopteryx (∼150 Ma). However, both approaches entail considerable uncertainties: for example, nonpreservation of fossils always underestimates the antiquity of lineages, whereas rate heterogeneity, saturation, and calibration uncertainty can strongly bias molecular divergence dating.
M. S. Y. Lee;A. Cau;D. Naish;G. J. Dyke
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/398814
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 76
  • ???jsp.display-item.citation.isi??? 79
social impact