Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 10 July 2009:
Vol. 325. no. 5937, pp. 193 - 196
DOI: 10.1126/science.1173826
Prev | Table of Contents | Next

Reports

Evolution of the Turtle Body Plan by the Folding and Creation of New Muscle Connections

Hiroshi Nagashima,1 Fumiaki Sugahara,1,2 Masaki Takechi,1 Rolf Ericsson,1,* Yoshie Kawashima-Ohya,1,{dagger} Yuichi Narita,1,{ddagger} Shigeru Kuratani1,§

The turtle shell offers a fascinating case study of vertebrate evolution, based on the modification of a common body plan. The carapace is formed from ribs, which encapsulate the scapula; this stands in contrast to the typical amniote body plan and serves as a key to understanding turtle evolution. Comparative analyses of musculoskeletal development between the Chinese soft-shelled turtle and other amniotes revealed that initial turtle development conforms to the amniote pattern; however, during embryogenesis, lateral rib growth results in a shift of elements. In addition, some limb muscles establish new turtle-specific attachments associated with carapace formation. We propose that the evolutionary origin of the turtle body plan results from heterotopy based on folding and novel connectivities.

1 Laboratory for Evolutionary Morphology, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minami, Kobe 650-0047, Japan.
2 Graduate School of Science, Kobe University, Kobe 657-8501, Japan.

* Present address: Department of Biological Sciences, Macquarie University, 2109 Sydney, Australia.

{dagger} Present address: Laboratory of Immunology, Department of Health Pharmacy, Yokohama College of Pharmacy, 601 Matano-cho, Yokohama 245-0066, Japan.

{ddagger} Present address: Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.

§ To whom correspondence should be addressed. E-mail: saizo{at}cdb.riken.jp

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
How Did the Turtle Get Its Shell?.
O. Rieppel (2009)
Science 325, 154-155
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)