Confirmation of the Passive Exhalation Hypothesis for a Terrestrial Caecilian, Dermophis mexicanus

Bennett, Wallace O.; Summers, Adam P.; Brainerd, Elizabeth L.

doi:10.2307/1447404

Cited by 9 publications

(1 citation statement)

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“…Prior studies have described the biomechanics of the hyobranchial buccal pump and the role of axial muscles in exhalation in lissamphibians ( Brainerd et al. 1993 ; Brainerd and Monroy 1998 ; Brainerd 1998 , 1999 ; Bennett et al. 1999 ; Simons et al.…”

Section: Introductionmentioning

confidence: 99%

Eye Movements in Frogs and Salamanders—Testing the Palatal Buccal Pump Hypothesis

Witzmann

Brainerd

Konow

2019

Integrative Organismal Biology

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Synopsis In frogs and salamanders, movements of the eyeballs in association with an open palate have often been proposed to play a functional role in lung breathing. In this “palatal buccal pump,” the eyeballs are elevated during the lowering of the buccal floor to suck air in through the nares, and the eyeballs are lowered during elevation of the buccal floor to help press air into the lungs. Here, we used X-Ray Reconstruction of Moving Morphology to investigate eye movements during lung breathing and feeding in bullfrogs and axolotls. Our data do not show eye movements that would be in accordance with the palatal buccal pump. On the contrary, there is a small passive elevation of the eyeballs when the buccal floor is raised. Inward drawing of the eyeballs occurs only during body motion and for prey transport in bullfrogs, but this was not observed in axolotls. Each eye movement in bullfrogs has a vertical, a mediolateral, and an anteroposterior component. Considering the surprisingly weak posterior motion component of the eyeballs, their main role in prey transport might be fixing the prey by pressing it against the buccal floor. The retraction of the buccal floor would then contribute to the posterior push of the prey. Because our study provides no evidence for a palatal buccal pump in frogs and salamanders, there is also no experimental support for the idea of a palatal buccal pump in extinct temnospondyl amphibians, in contrast to earlier suggestions.

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Section: Introductionmentioning

confidence: 99%