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Stiffening the stingray skeleton — an investigation of durophagy in Myliobatid stingrays (Chondrichthyes, Batoidea, Myliobatidae)
Article first published online: 4 FEB 2000
DOI: 10.1002/(SICI)1097-4687(200002)243:2<113::AID-JMOR1>3.0.CO;2-A
Copyright © 2000 Wiley-Liss, Inc.
1097-4687/asset/cover.gif?v=1&s=ec0ae2c4806f8103dbc94ab6157da96a801db7b4 "Journal of Morphology")
Additional Information
How to Cite
Summers, A. P. (2000), Stiffening the stingray skeleton — an investigation of durophagy in Myliobatid stingrays (Chondrichthyes, Batoidea, Myliobatidae). Journal of Morphology, 243: 113–126. doi: 10.1002/(SICI)1097-4687(200002)243:2<113::AID-JMOR1>3.0.CO;2-A
Publication History
- Issue published online: 4 FEB 2000
- Article first published online: 4 FEB 2000
Funded by
- the National Science Foundation. Grant Number: IBN 9801636
- the Organismic and Evolutionary Biology Program at the University of Massachusetts
- Abstract
- References
- Cited By
Keywords:
- hard prey;
- cartilage;
- calcification;
- ontogeny;
- jaws;
- feeding
Abstract
ABSTRACT
The stingray family Myliobatidae contains five durophagous (hard prey specialist) genera and two planktivorous genera. A suite of morphological features makes it possible for the hard prey specialists to crush mollusks and crustaceans in their cartilaginous jaws. These include: 1) flat, pavement-like tooth plates set in an elastic dental ligament; 2) multiple layers of calcified cartilage on the surface of the jaws; 3) calcified struts running through the jaws; and 4) a lever system that amplifies the force of the jaw adductors. Examination of a range of taxa reveals that the presence of multiple layers of calcified cartilage, previously described from just a few species, is a plesiomorphy of Chondrichthyes. Calcified struts within the jaw, called “trabecular cartilage,” are found only in the myliobatid genera, including the planktivorous Manta birostris. In the durophagous taxa, the struts are concentrated under the area where prey is crushed, thereby preventing local buckling of the jaws. Trabecular cartilage develops early in ontogeny, and does not appear to develop as a direct result of the stresses associated with feeding on hard prey. A “nutcracker” model of jaw function is proposed. In this model, the restricted gape, fused mandibular and palatoquadrate symphyses, and asynchronous contraction of the jaw adductors function to amplify the closing force by 2–4 times. J. Morphol. 243:113–126, 2000 © 2000 Wiley-Liss, Inc.