Meeting Abstract

P3.146  Wednesday, Jan. 6  Scaling relationships of the tongue apparatus in the family Chamaeleonidae SHERIDAN, T.A.*; ANDERSON, C.V.; DEBAN, S.M.; University of South Florida tsherida@mail.usf.edu

The feeding mechanism of old world chameleons (Family Chamaeleonidae) is highly specialized and produces extreme performance via its spring-loaded projection mechanism. While many musculoskeletal systems of ectotherms scale with near isometry, we hypothesize that the chameleon tongue apparatus may scale differently because muscles are launched ballistically from the mouth and may be subject to additional constraints on their proportions. Spring-based systems may scale differently than muscle-based systems by virtue of their extreme performance. We determined scaling relationships of the chameleon feeding apparatus from a total of 59 individuals representing 16 species from 7 genera of the family Chamaeleonidae. Specimens ranged in snout-vent length (SVL) from 37 – 223 mm. We find based on the log-transformed measurements that entoglossus (ENT) length is negatively allometric to both SVL (0.83 ± 0.09; mean slope ± 95% conf. int.) and jaw length (0.89 ± 0.07). The mass of the posterior, circular portion of the accelerator muscle (2.76 ± 0.28) and the retractor muscle (2.85 ± 0.37) scale geometrically to ENT length. In addition to addressing questions about the scaling relationships of this spring-based system and its potential constraints, these scaling relationships aid in calculation of mass-specific performance parameters based on external measurements when applied to feeding performance in animals of a range of body sizes.