Sunday, December 13, 2015

Oviraptors and Alvarezsaurids within Euparaves

In the previous post, we saw analyses from 2009, 2011, 2013, 2014 and 2015 that show oviraptors and/or alvarezsaurids to be within Euparaves. (In other words, within the clade based on the common ancestor of Epidendrosaurus and Gallus).

What are the basalmost taxa within Euparaves? They are the Scansoriopterygidae, Anchiornis, Aurornis, Xiaotingia and Pedopenna. They are flying, arboreal, primitive birds.

On the other hand, Oviraptors and Alvarezsaurids were ground-based. They were secondarily flightless, as some previous analyses have found.

What is the significance of this? It means that Oviraptors and Alvarezsaurids are not intermediate (not outgroups) between dinosaurs and flying primitive birds.
That is like having the foundation of the dino to bird theory kicked out. There is no connection between dinosaurs and primitive birds.

As a sidenote, keep in mind also that Eudromaeosaurids are secondarily flightless, primitive birds within Euparaves. They are not intermediate (not outgroups) between dinosaurs and flying primitive birds.

1 comment:

  1. For reference:
    Here we show that although basal living birds apparently have retained the dinosaurian condition in which the sternum develops from a bilateral pair of ossifications (present in paravian dinosaurs and basal birds)