Alligator (Archosauria) "air sacs"

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com

A new online paper not yet mentioned on the DML:


R. Kent Sanders & C.G. Farmer (2012)
The Pulmonary Anatomy of Alligator mississippiensis and Its Similarity
to the Avian Respiratory System.
The Anatomical Record: Advances in Integrative Anatomy and
Evolutionary Biology (advance online publication)
DOI: 10.1002/ar.22427
http://onlinelibrary.wiley.com/doi/10.1002/ar.22427/abstract


Using gross dissections and computed tomography we studied the lungs
of juvenile American alligators (Alligator mississippiensis). Our
findings indicate that both the external and internal morphology of
the lungs is strikingly similar to the embryonic avian respiratory
system (lungs + air sacs). We identified bronchi that we propose are
homologous to the avian ventrobronchi (entobronchi), laterobronchi,
dorsobronchi (ectobronchi), as well as regions of the lung
hypothesized to be homologous to the cervical, interclavicular,
anterior thoracic, posterior thoracic, and abdominal air sacs.
Furthermore, we suggest that many of the features that alligators and
birds share are homologous and that some of these features are
important to the aerodynamic valve mechanism and are likely
plesiomorphic for Archosauria.