A novel accessory respiratory muscle in the American alligator ( Alligator mississippiensis)

Research output: Contribution to journalArticle

  • External authors:
  • Kayleigh A.R. Rose
  • Peter G. Tickle
  • Robert J. Brocklehurst
  • Ruth M. Elsey
  • Dane A. Crossley


The muscles that effect lung ventilation are key to understanding the evolutionary constraints on animal form and function. Here, through electromyography, we demonstrate a newly discovered respiratory function for the iliocostalis muscle in the American alligator ( Alligator mississippiensis). The iliocostalis is active during expiration when breathing on land at 28°C and this activity is mediated through the uncinate processes on the vertebral ribs. There was also an increase in muscle activity during the forced expirations of alarm distress vocalizations. Interestingly, we did not find any respiratory activity in the iliocostalis when the alligators were breathing with their body submerged in water at 18°C, which resulted in a reduced breathing frequency. The iliocostalis is an accessory breathing muscle that alligators are able to recruit in to assist expiration under certain conditions.

Bibliographical metadata

Original languageEnglish
Number of pages1
JournalBiology letters
Issue number7
Early online date3 Jul 2019
Publication statusPublished - 2019

Related information