Cranial kinesis in the miniaturised lizard Ablepharus kitaibelii (Squamata: Scincidae).

Autor:	Handschuh S; VetCore Facility for Research/Imaging Unit, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna 1210, Austria stephan.handschuh@vetmeduni.ac.at., Natchev N; Department Biology, Faculty of Natural Sciences, Shumen University, Universitetska 115, 9700 Shumen, Bulgaria., Kummer S; VetCore Facility for Research/Imaging Unit, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna 1210, Austria., Beisser CJ; Department for Integrative Zoology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria., Lemell P; Department for Integrative Zoology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria., Herrel A; UMR 7179 C.N.R.S/M.N.H.N., Département Adaptations du Vivant, Bâtiment d'Anatomie Comparée, 55 rue Buffon, Paris 75005, France., Vergilov V; National Museum of Natural History, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, Sofia 1000, Bulgaria.
Jazyk:	angličtina
Zdroj:	The Journal of experimental biology [J Exp Biol] 2019 May 10; Vol. 222 (Pt 9). Date of Electronic Publication: 2019 May 10.
DOI:	10.1242/jeb.198291
Abstrakt:	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-crank model by placing a special emphasis on metakinesis. According to this model, we hypothesise that metakinetic intracranial movements may provide a means for reducing strain in jaw adductor muscles. Presented hypotheses can be addressed and tested in future studies. Competing Interests: Competing interestsThe authors declare no competing or financial interests. (© 2019. Published by The Company of Biologists Ltd.)
Databáze:	MEDLINE
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