Modeling neck mobility in fossil turtles
Version of Record online: 4 FEB 2014
© 2014 Wiley Periodicals, Inc.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution
Special Issue: Turtle Origins and Evolution
Volume 324, Issue 3, pages 230–243, May 15, 2015
How to Cite
2014. Modeling neck mobility in fossil turtles. J. Exp. Zool. (Mol. Dev. Evol.) 324B:230–243., , , , , .
- Issue online: 15 APR 2015
- Version of Record online: 4 FEB 2014
- Manuscript Accepted: 23 DEC 2013
- Manuscript Revised: 18 DEC 2013
- Manuscript Received: 15 OCT 2013
- Deutsche Forschungsgemeinschaft. Grant Number: JO 928/1
Turtles have the unparalleled ability to retract their heads and necks within their shell but little is known about the evolution of this trait. Extensive analysis of neck mobility in turtles using radiographs, CT scans, and morphometry reveals that basal turtles possessed less mobility in the neck relative to their extant relatives, although the anatomical prerequisites for modern mobility were already established. Many extant turtles are able to achieve hypermobility by dislocating the central articulations, which raises cautions about reconstructing the mobility of fossil vertebrates. A 3D-model of the Late Triassic turtle Proganochelys quenstedti reveals that this early stem turtle was able to retract its head by tucking it sideways below the shell. The simple ventrolateral bend seen in this stem turtle, however, contrasts with the complex double-bend of extant turtles. The initial evolution of neck retraction therefore occurred in a near-synchrony with the origin of the turtle shell as a place to hide the unprotected neck. In this early, simplified retraction mode, the conical osteoderms on the neck provided further protection. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 230–243, 2015. © 2014 Wiley Periodicals, Inc.