September 30, 2008

Aerosteon riocoloradensis

12:14 am
  • New Dinosaur: Aerosteon riocoloradensis
  • Name Means: Air bones from the Rio Colorado
  • Relations: Basal (allosauroid?) tetanuran theropod
  • Size: 9 meters/30 feet long
  • Location: Cañadon Amarillo, Argentina
  • Age: Late Cretaceous, ~84,000,000 years ago
  • Info:

    Key to the pneumatic features reported in Aerosteon riocoloradensis
    from Sereno et al. 2008. See here for detailed caption.

    The fossilized bones of Aerosteon are extensively pneumatized— that is, riddled with hollow spaces. In life, some of these spaces would have housed air sacs that helped maintain a steady flow of air through the dinosaur’s rigid lungs. Modern birds have inherited this type of respiratory system from their dinosaurian ancestors, who may have developed this distinctive aerated anatomy in order to breathe more efficiently, or lighten their load and keep balance while running on two legs, or as a built-in air-cooling system to keep from overheating. The extreme degree of pneumatization preserved in a relatively primitive theropod like Aerosteon helps researchers pinpoint when specific features of the avian respiratory system first evolved.

  • Reference: Sereno, P. C., Martinez, R. N., Wilson, J. A., Varricchio, D. J., Alcober, O. A., Larsson, H. C. E., 2008. Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina PLoS ONE 3(9): e3303. doi10.1371/journal.pone.0003303.
  • Web coverage:
  • Update 10/6: Matt Wedel reviews the current state of research on dinosaur pneumaticity and raises some criticisms of Sereno et al.’s paper describing Aerosteon in two posts over on SV-POW.
  • Update 10/31: In the comments to the PLOS One paper, Paul Sereno has labeled Wedel’s above-mentioned criticisms as “a misleading, ad-hominem critique”, and Matt Wedel has responded to the comment at SV-POW.
  • Update 11/7: Commentary continues:

    I was alerted to the latest updates from the Dinosaur Mailing List.

—Matt Celeskey.

September 29, 2008

Critters with great big claws on their fingers

6:45 am

You could almost say, “Critters whose great big claws are their fingers”:

—Matt Celeskey.

September 28, 2008

Schematic drawing of hypothesized trends in hair evolution from a synapsid-scaled integument

5:14 pm

I couldn’t improve upon the existing caption to this intriguing image, which accompanies this intriguing article.

Albardi, L. 2004. Comparative aspects of the inner root sheath in adult and developing hairs of mammals in relation to the evolution of hairs. Journal of Anatomy 205: 3, pp. 179-200.

—Matt Celeskey.

September 27, 2008

In which a pleurodire of the genus Elusor is adorned with filamentous algae in an amusingly anthropormorphic fashion

5:07 pm

The “punk rock” Mary River turtle as reported in The Daily Mail.

—Matt Celeskey.

September 25, 2008

Several actinopterygians possessing distinct morphologies, presented in brief overview through the use of moving images and ethereo-pelagic harmonies.

10:07 pm

Adam Gault’s Lantern Fishes.


—Matt Celeskey.