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RE: K-Pg extinction global firestorms
David Marjanovic wrote:
>> And according to Phillips et. all (2009) four separate paleognath
>> lineages survived the K-T event.
>So? What calibration dates did they use?
>> Brown and van Tuinen (2011) note in figure 12.1,
>> anseriforms and galliforms may have diverged 80 mya.
>Again, based on what evidence?
In the former it is based on the mitochondrial genomes of a large sample of
birds, including subfossil moas. The latter is a review of methodologies. One
molecular genetic timescale they give (Fig. 12.1) is based on Hackett et al.
(2008) "utilizing a Bayesian uncorrelated lognormally-distributed relaxed
molecular clock in BEAST (Brown et al., unpublished data)."
But they spend a great deal of space discussing their evidence and methods so
it is best if you read the papers rather than have me paraphrase. I'll give you
the references once more here if that helps.
Phillips MJ, Gibb GC, Crimp EA, Penny D 2010 Tinamous and moa flock
together: mitochondrial genome sequence analysis reveals independent
losses of flight among ratites. Syst Biol 59(1): 90–107
Brown JW, van Tuinen M 2011 Evolving perceptions on the antiquity of
the modern avian tree. 306–24 _in_ Dyke GJ, Kaiser G, eds. _Living
Dinosaurs: The Evolutionary History of Modern Birds_. London: John
Wiley and Sons