Development of the pharyngeal dentition of two herbivorous halfbeaks, Hyporhamphus regularis ardelio (Whitley, 1931) and Arrhamphus sclerolepis krefftii (Steindachner, 1867), was examined quantitatively to assess features that might confer their ability to shift their diet from animal to plant material. Toothed area, tooth number, maximum tooth diameter and tooth wear area in both pharyngeal tooth pads of both taxa increased with ontogeny, whereas tooth density decreased. Comparing individuals of the two taxa at similar standard lengths indicated that A. sclerolepis krefftii showed hypertrophy of the majority of pharyngeal characters in relation to H. regularis ardelio of a similar standard length. That A. sclerolepis krefftii is more developmentally advanced than H. regularis ardelio in almost all dentigerous characters studied indicates that pharyngeal development may allow the former to commence herbivory at a smaller standard length than the latter species. The evolutionary and ecological implications of these findings are discussed in the context of a group of fishes that is overexploited worldwide.

Item Type:	Refereed Article
Keywords:	enameloid, mechanical digestion, ontogeny, tooth replacement, wear surface
Research Division:	Biological Sciences
Research Group:	Zoology
Research Field:	Animal Structure and Function
Objective Division:	Environment
Objective Group:	Flora, Fauna and Biodiversity
Objective Field:	Marine Flora, Fauna and Biodiversity
Author:	Day, RD (Dr Ryan Day)
ID Code:	95718
Year Published:	2008
Web of Science® Times Cited:	5
Deposited By:	Sustainable Marine Research Collaboration
Deposited On:	2014-10-08
Last Modified:	2014-11-26
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