Hairy Museum of Natural History

• 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:
  • Press Release
  • Blog Around the Clock: Aerosteon riocoloradensis- the new dinosaur with hollow bones.
  • Greg Laden’s Blog: Aerosteon riocoloradensis: A Very Cool Dinosaur from Argentina
• 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:
  • Brian Switek weighs in on the back-and-forth in a post on Smithsonian.com’s Dinosaur Tracking blog
  • In a comment to Switek’s post, Paul Sereno notes that a more detailed response to Wedel’s critiques is available at his website.

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

—Matt Celeskey.

File under: Cretaceous, Dinosaurs.