Monday, August 04, 2014

How Theropod Dinosaurs Became Birds




Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds

Authors:

Lee et al

Abstract:

Recent discoveries have highlighted the dramatic evolutionary transformation of massive, ground-dwelling theropod dinosaurs into light, volant birds. Here, we apply Bayesian approaches (originally developed for inferring geographic spread and rates of molecular evolution in viruses) in a different context: to infer size changes and rates of anatomical innovation (across up to 1549 skeletal characters) in fossils. These approaches identify two drivers underlying the dinosaur-bird transition. The theropod lineage directly ancestral to birds undergoes sustained miniaturization across 50 million years and at least 12 consecutive branches (internodes) and evolves skeletal adaptations four times faster than other dinosaurs. The distinct, prolonged phase of miniaturization along the bird stem would have facilitated the evolution of many novelties associated with small body size, such as reorientation of body mass, increased aerial ability, and paedomorphic skulls with reduced snouts but enlarged eyes and brains.

One of the authirs, Darren Naish, has a blog post on the paper.

7 comments:

Anonymous said...

The number at Pennaraptora seems to be 2.182. It looks like you changed it from 2.382 in the article. Am I right?

Will Baird said...

Didn't change anything.

Anonymous said...

You did darken the decimal points? Yes?

Will Baird said...

nope. took a screen shot, if you're referring to the graphs above, from the paper itself.

Anonymous said...

Did you take the screen shot from Figure S1 at this link:
https://www.academia.edu/7832790/Lee_M.S.Y._Cau_A._Naish_D._Dyke_G.J._2014._Sustained_miniaturization_and_anatomical_innovation_in_the_dinosaurian_ancestors_of_birds._Science_345_562-566_NOTE_SM_below_has_hi-res_figures_which_were_pixellated_on_the_Science_SM_pdf_

Anonymous said...

My mistake. Did you take it from this link:
http://www.researchgate.net/publication/264386153_Sustained_miniaturization_and_anatomical_innovation_in_the_dinosaurian_ancestors_of_birds

Will Baird said...

I got it from here:

http://www.sciencemag.org/content/345/6196/562.abstract