Cranial kinesis in the miniaturised lizard Ablepharus kitaibelii (Squamata: Scincidae) [RESEARCH ARTICLE]

Stephan Handschuh, Nikolay Natchev, Stefan Kummer, Christian J. Beisser, Patrick Lemell, Anthony Herrel, and Vladislav Vergilov
Cranial kinesis refers to intracranial movements in the vertebrate skull that do not concern the jaw joint, the middle ear or the hypobranchial skeleton. Different kinds of cranial kinesis have been reported for lizards, including mesokinesis, metakinesis, amphikinesis (simultaneous mesokinesis and metakinesis) and streptostyly. Streptostyly is considered relatively widespread within lizards, whereas mesokinesis has been documented only for geckos, varanids and anguids. The present study investigated cranial kinesis in the miniaturised scincid Ablepharus kitaibelii by integrating morphological and experimental data. Based on micro computed tomography, we provide a description of skull osteology. Cranial joints were studied with histology, which results in the first detailed description of cranial joint histology for a member of the Scincidae. Taken together, the morphological data indicate a high potential for amphikinesis and streptostyly, which was also corroborated by skull manipulations. High-speed cinematography demonstrated that mesokinesis occurs during food uptake, processing and intraoral transport cycles. Bite force measurements showed prolonged and reasonably hard biting even at large gape angles. Based on these data, we formulate a model of the amphikinetic A. kitaibelii skull mechanism, which provides an extension of Frazzetta's quadric...

Source: Journal of Experimental Biology - May 9, 2019 Category: Biology Authors: Handschuh, S., Natchev, N., Kummer, S., Beisser, C. J., Lemell, P., Herrel, A., Vergilov, V. Tags: RESEARCH ARTICLE Source Type: research