Kinematics of Tongue Projection in Chamaeleo Oustaleti

The kinematics of prey capture by the chamaeleonid lizard Chamaeleo oustaleti were studied using high-speed cinematography. Three feeding sequences from each of two individuals were analyzed for strike distances of 20 and 35 cm, at 30°C. Ten distances and angles were measured from sequential frames beginning approximately 0.5 s prior to tongue projection and continuing for about 1.0 s. Sixteen additional variables, documenting maximum excursions and the timing of events, were calculated from the kinematic profiles. Quantified descriptions of head, hyoid and tongue movements are presented. Previously unrecognized rapid protraction of the hyobranchial skeleton simultaneously with the onset of tongue projection was documented and it is proposed that this assists the accelerator muscle in powering tongue projection. Acceleration of the tongue occurred in about 20ms, reaching a maximum acceleration of 486 m s−2 and maximum velocity of 5.8m s−1 in 35 cm strikes. Deceleration of the tongue usually began within 5 ms before prey contract and the direction of tongue movement was reversed within 10 ms of prey contact. Retraction of the tongue, caused by shortening of the retractor muscles, reached a maximum velocity of 2.99 ms−1 and was complete 330 ms after prey contact. Projection distance influences many aspects of prey capture kinematics, particularly projection time, tongue retraction time and the extent of gape and head movements during tongue retraction, all of which are smaller in shorter feedings. Though several features of the chameleon strike have apparently been retained from lizards not capable of ballistic tongue projection, key differences are documented. Unlike members of a related family, the Agamidae, C. oustaleti uses no body lunge during prey capture, exhibits gape reduction during tongue projection and strongly depresses the head and jaws during tongue retraction. Note: Present address: Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA.

[1]  A. F. Bennett,et al.  Kinematics of prey processing in Chamaeleo jacksonii: conservation of function with morphological specialization , 1992 .

[2]  W. W. Tanner,et al.  Buccal floor of reptiles, A summary , 1982 .

[3]  G. Lauder,et al.  PHYSIOLOGICAL BASES OF FEEDING BEHAVIOUR IN SALAMANDERS: DO MOTOR PATTERNS VARY WITH PREY TYPE? , 1989 .

[4]  LINDESAY HARKNESS,et al.  Chameleons use accommodation cues to judge distance , 1977, Nature.

[5]  Robert W. Blake,et al.  Short Communication: A Critical Analysis of the Use of High-Speed Film to Determine Maximum Accelerations of Fish , 1989 .

[6]  A. Zood,et al.  The Mechanism of Projection of the Chameleon's Tongue , 1933 .

[7]  Functional anatomy of the chameleon tongue , 1989 .

[8]  John T. Beneski,et al.  Hyolingual feeding systems of the Plethodontidae: Comparative kinematics of prey capture by salamanders with free and attached tongues , 1989 .

[9]  G. Lauder,et al.  Evolution of motor patterns: aquatic feeding in salamanders and ray-finned fishes. , 1989, Brain, behavior and evolution.

[10]  W. Kier,et al.  Tongues, tentacles and trunks: the biomechanics of movement in muscular‐hydrostats , 1985 .

[11]  K. Queiroz**,et al.  Phylogenetic relationships within squamata , 1988 .

[12]  G. Throckmorton,et al.  Functional and evolutionary morphology of lingual feeding in squamate reptiles: phylogenetics and kinematics , 1989 .

[13]  D. Kraklau.  Kinematics of prey capture and chewing in the lizard Agama agama (squamata: Agamidae) , 1991, Journal of morphology.

[14]  Paul W. Webb,et al.  EFFECTS OF MEDIAN-FIN AMPUTATION ON FAST-START PERFORMANCE OF RAINBOW TROUT (SALMO GAIRDNERI) , 1977 .

[15]  C. P. Gnanamuthu,et al.  The anatomy and mechanism of the tongue of Chamadeon carcaratus (Merrem) , 1930 .

[16]  D. Wake,et al.  Tongue evolution in the lungless salamanders, family plethodontidae. II. Function and evolutionary diversity , 1977 .

[17]  G. Lauder,et al.  THE EVOLUTION OF TETRAPOD FEEDING BEHAVIOR: KINEMATIC HOMOLOGIES IN PREY TRANSPORT , 1990, Evolution; international journal of organic evolution.

[18]  Sanders Sl.  Variation in neuromuscular activity during prey capture by trophic specialists and generalists (Pisces: Labridae). , 1988 .

[19]  Robert W. Blake,et al.  Energetics of piscivorous predator-prey interactions , 1988 .

[20]  H. Shaffer,et al.  PATTERNS OF VARIATION IN AQUATIC AMBYSTOMATID SALAMANDERS: KINEMATICS OF THE FEEDING MECHANISM , 1985, Evolution; international journal of organic evolution.

[21]  H. Shaffer,et al.  Aquatic prey capture in ambystomatid salamanders: Patterns of variation in muscle activity , 1985, Journal of morphology.

[22]  Kinematics of prey capture in the chameleon , 1990 .

[23]  Kathleen K Smith.  Form and function of the tongue in agamid lizards with comments on its phylogenetic significance , 1988, Journal of morphology.

[24]  D. Wake,et al.  Tongue evolution in the lungless salamanders, family plethodontidae I. Introduction, theory and a general model of dynamics , 1976, Journal of morphology.

[25]  Martha Flanders,et al.  Visually guided head movement in the African chameleon , 1985, Vision Research.

[26]  A. Krall.  Applied Analysis , 1986 .

[27]  R. Greenberg.  Biometry , 1969, The Yale Journal of Biology and Medicine.

[28]  S. J. Arnold,et al.  Morphology, Performance and Fitness , 1983 .

[29]  Robert W. Blake,et al.  On the error involved in high-speed film when used to evaluate maximum accelerations of fish , 1989 .

[30]  M. Rice.  Supercontracting Striated Muscle in a Vertebrate , 1973, Nature.