title: Slow but tenacious: an analysis of running and gripping performance in chameleons.
abstract: Chameleons are highly specialized and mostly arboreal lizards characterized by a suite of derived characters. The grasping feet and tail are thought to be related to the arboreal lifestyle of chameleons, yet specializations for grasping are thought to exhibit a trade-off with running ability. Indeed, previous studies have demonstrated a trade-off between running and clinging performance, with faster species being poorer clingers. Here we investigate the presence of trade-offs by measuring running and grasping performance in four species of chameleon belonging to two different clades (Chamaeleo and Bradypodion). Within each clade we selected a largely terrestrial species and a more arboreal species to test whether morphology and performance are related to habitat use. Our results show that habitat drives the evolution of morphology and performance but that some of these effects are specific to each clade. Terrestrial species in both clades show poorer grasping performance than more arboreal species and have smaller hands. Moreover, hand size best predicts gripping performance, suggesting that habitat use drives the evolution of hand morphology through its effects on performance. Arboreal species also had longer tails and better tail gripping performance. No differences in sprint speed were observed between the two Chamaeleo species. Within Bradypodion, differences in sprint speed were significant after correcting for body size, yet the arboreal species were both better sprinters and had greater clinging strength. These results suggest that previously documented trade-offs may have been caused by differences between clades (i.e. a phylogenetic effect) rather than by design conflicts between running and gripping per se.
authors.affiliation: UMR 7179 CNRS/MNHN, Département d'Ecologie et de Gestion de la Biodiversité, 57 rue Cuvier, Case postale 55, 75231, Paris Cedex 5, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Herrel
authors.forename: Krystal A
authors.initials: KA
authors.lastname: Tolley
authors.forename: G John
authors.initials: GJ
authors.lastname: Measey
authors.forename: Jessica M
authors.initials: JM
authors.lastname: da Silva
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Potgieter
authors.forename: Elodie
authors.initials: E
authors.lastname: Boller
authors.forename: Renaud
authors.initials: R
authors.lastname: Boistel
authors.forename: Bieke
authors.initials: B
authors.lastname: Vanhooydonck
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D005075:Biological Evolution; D001837:Body Weights and Measures; D017753:Ecosystem; D005552:Forelimb / Q000033:anatomy & histology; D018737:Hand Strength / Q000502:physiology*; D008116:Lizards / Q000033:anatomy & histology / Q000502:physiology*; D012420:Running / Q000502:physiology*; D013019:South Africa; D013045:Species Specificity; D013623:Tail / Q000033:anatomy & histology / Q000502:physiology*