Comparative study of tongue protrusion in three iguanian lizards, Sceloporus undulatus, Pseudotrapelus sinaitus and Chamaeleo jacksonii

J. J. Meyers, K. C. Nishikawa

Research output: Contribution to journalArticle

26 Scopus citations


The goal of this study was to investigate the function of the hyolingual muscles used during tongue protraction in iguanian lizards. High-speed videography and nerve-transection techniques were used to study prey capture in the iguanid Sceloporus undulatus, the agamid Pseudoptrapelus sinaitus and the chameleonid Chamaeleo jacksonii. Denervation of the mandibulohyoideus muscle slips had an effect only on P. sinaitus and C. jacksonii, in which tongue protrusion or projection distance was reduced. In C. jacksonii, denervation of the M. mandibulohyoideus completely prevented little hyoid protraction. Denervation of the M. verticalis had no effect on S. undulatus, but reduced tongue protrusion distance in P. sinaitus. Denervation of the accelerator muscle in C. jacksonii inhibited tongue projection completely. The function of the M. mandibulohyoideus and M. verticalis has become increasingly specialized in P. sinaitus and especially in C. jacksonii to allow greater tongue protrusion. The combined results of these treatments suggest that these three groups represent transitional forms, both morphologically and functionally, in the development of a projectile tongue.

Original languageEnglish (US)
Pages (from-to)2833-2849
Number of pages17
JournalJournal of Experimental Biology
Issue number18
StatePublished - Jan 1 2000



  • Agamidae
  • Chamaeleo jacksonii
  • Chamaeleonidae
  • Iguanidae
  • Kinematics
  • Lizard
  • Nerve transection
  • Prey capture
  • Pseudotrapelus sinaitus
  • Reptile
  • Sceloporus undulatus
  • Tongue protrusion

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Insect Science

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