The Fifth muscle of the Amphibian Larynx
Poster Number
23
Format
Poster Presentation
Faculty Mentor Name
Marcos Gridi-Papp
Faculty Mentor Department
Biological Sciences
Abstract/Artist Statement
Frogs protect their airways with a pair of arytenoid cartilages. Four pairs of laryngeal muscles lay on top of these cartilages: one dilator and three constrictors (anterior posterior and external). The dilator separates the arytenoid cartilages for breathing, while the constrictors close them. Panamanian tungara frogs (Engystomops pustulosus) might exhibit a fifth laryngeal muscle. As in other frogs, the dilator muscles of tungaras extend from a narrow attachment of the posteromedial process of the hyoid cartilage to a broad attachment along the center of the arytenoid cartilage's medial edge. The new muscle lies deep to the dilator muscle and it has a broader attachment to the medial edges of the arytenoid cartilages. Its fibers converge to pass through a slit between the arytenoid and cricoid cartilages and attach to the large fibrous mass. This renders the new muscle less well positioned than the dilators to open the arytenoids, and its contraction is more likely to produce a lateral displacement of the fibrous masses. Tungara frogs have a large larynx with a pair of greatly enlarged fibrous masses. Their vibration allows males to facultatively add notes with distinctive acoustic structure to their calls, enhancing their attractiveness. We are currently analyzing the innervations of the two muscles through histology, dissection, and stimulation in isolated larynges to elucidate the function of the new muscle and determine whether it is a derived feature of tungara frogs or an ancestral feature that may be less evident in species studied previously.
Location
DeRosa University Center, Ballroom
Start Date
26-4-2014 2:00 PM
End Date
26-4-2014 4:00 PM
The Fifth muscle of the Amphibian Larynx
DeRosa University Center, Ballroom
Frogs protect their airways with a pair of arytenoid cartilages. Four pairs of laryngeal muscles lay on top of these cartilages: one dilator and three constrictors (anterior posterior and external). The dilator separates the arytenoid cartilages for breathing, while the constrictors close them. Panamanian tungara frogs (Engystomops pustulosus) might exhibit a fifth laryngeal muscle. As in other frogs, the dilator muscles of tungaras extend from a narrow attachment of the posteromedial process of the hyoid cartilage to a broad attachment along the center of the arytenoid cartilage's medial edge. The new muscle lies deep to the dilator muscle and it has a broader attachment to the medial edges of the arytenoid cartilages. Its fibers converge to pass through a slit between the arytenoid and cricoid cartilages and attach to the large fibrous mass. This renders the new muscle less well positioned than the dilators to open the arytenoids, and its contraction is more likely to produce a lateral displacement of the fibrous masses. Tungara frogs have a large larynx with a pair of greatly enlarged fibrous masses. Their vibration allows males to facultatively add notes with distinctive acoustic structure to their calls, enhancing their attractiveness. We are currently analyzing the innervations of the two muscles through histology, dissection, and stimulation in isolated larynges to elucidate the function of the new muscle and determine whether it is a derived feature of tungara frogs or an ancestral feature that may be less evident in species studied previously.