Hard prey, soft jaws and the ontogeny of feeding mechanics in the spotted ratfish Hydrolagus colliei.

Full Abstract

The spotted ratfish Hydrolagus colliei is a holocephalan fish that consumes hard prey (durophagy) but lacks many morphological characters associated with durophagy in other cartilaginous fishes. We investigated its feeding biomechanics and biting performance to determine whether it can generate bite forces comparable with other durophagous elasmobranchs, how biting performance changes over ontogeny (21-44 cm SL) and whether biomechanical modelling can accurately predict feeding performance in holocephalans. Hydrolagus colliei can generate absolute and mass-specific bite forces comparable with other durophagous elasmobranchs (anterior=104 N, posterior=191 N) and has the highest jaw leverage of any cartilaginous fish studied. Modelling indicated that cranial geometry stabilizes the jaw joint by equitably distributing forces throughout the feeding mechanism and that positive allometry of bite force is due to hyperallometric mechanical advantage. However, bite forces measured through tetanic stimulation of the adductor musculature increased isometrically. The jaw adductors of H. colliei fatigued more rapidly than those of the piscivorous spiny dogfish Squalus acanthias as well. The feeding mechanism of H. colliei is a volume-constrained system in which negative allometry of cranial dimensions leaves relatively less room for musculature. Jaw adductor force, however, is maintained through ontogenetic changes in muscle architecture.

Author information

Author/s: Huber, Daniel R (DR); Dean, Mason N (MN); Summers, Adam P (AP);

Affiliation: Department of Biology, University of Tampa, 401 W. Kennedy Boulevard, Box U, Tampa, FL 33606, USA. dhuber(-atsign-)ut.edu

Journal and publication information

Publication Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.

Journal: Journal of the Royal Society, Interface / the Royal Society (J R Soc Interface), published in England. (Language: eng)

Reference: 2008-Aug; vol 5 (issue 25) : pp 941-52

Dates: Created 2008/06/23; Completed 2008/10/09; Revised 2009/08/07;

PMID: 18238758, status: MEDLINE (last retrieval date: 8/21/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

Comments and Corrections

ErratumIn: J R Soc Interface. 2008 Dec 6;5(29):1509-10.

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