Morphological and mechanical changes in juvenile red-eared slider turtle (Trachemys scripta elegans) shells during ontogeny
Article first published online: 3 DEC 2013
Copyright © 2013 Wiley Periodicals, Inc.
Journal of Morphology
Volume 275, Issue 4, pages 391–397, April 2014
How to Cite
Fish, J. F. and Stayton, C. T. (2014), Morphological and mechanical changes in juvenile red-eared slider turtle (Trachemys scripta elegans) shells during ontogeny. J. Morphol., 275: 391–397. doi: 10.1002/jmor.20222
- Issue published online: 6 MAR 2014
- Article first published online: 3 DEC 2013
- Manuscript Accepted: 3 OCT 2013
- Manuscript Revised: 6 SEP 2013
- Manuscript Received: 9 APR 2013
- DBI. Grant Number: 0743460
- IIS (T. Rowe). Grant Number: 0208675
Turtles experience numerous modifications in the morphological, physiological, and mechanical characteristics of their shells through ontogeny. Although a general picture is available of the nature of these modifications, few quantitative studies have been conducted on changes in turtle shell shape through ontogeny, and none on changes in strength or rigidity. This study investigates the morphological and mechanical changes that juvenile Trachemys scripta elegans undergo as they increase in size. Morphology and shell rigidity were quantified in a sample of 36 alcohol-preserved juvenile Trachemys scripta elegans. Morphometric information was used to create finite element models of all specimens. These models were used to assess the mechanical behavior of the shells under various loading conditions. Overall, we find that turtles experience complementary changes in size, shape, deformability, and relative strength as they grow. As turtles age their shells become larger, more elongate, relatively flatter, and more rigid. These changes are associated with decreases in relative (size independent) strength, even though the shells of larger turtles are stronger in an absolute sense. Decreased deformability is primarily due to changes in the size of the animals. Residual variation in deformability cannot be explained by changes in shell shape. This variation is more likely due to changes in the degree of connectedness of the skeletal elements in the turtle's shells, along with changes in the thickness and degree of mineralization of shell bone. We suggest that the mechanical implications of shell size, shape, and deformability may have a large impact on survivorship and development in members of this species as they mature. J. Morphol. 275:391–397, 2014. © 2013 Wiley Periodicals, Inc.