Meeting Abstract

25.6  Saturday, Jan. 4 14:45  Use it or lose it: locomotor evolution associated with the loss of adhesion in geckos HIGHAM, TE*; RUSSELL, AP; BIRN-JEFFERY, A; COLLINS, CE; HULSEY, CD; Univ. of California, Riverside; Univ. of Calgary; Univ. of California, Riverside; Univ. of California, Riverside; Univ. of Tennessee thigham@ucr.edu

Geckos are known for their remarkable ability to adhere to smooth and/or inclined surfaces using adhesive toe pads. As well as the multiple instances of the acquisition of adhesive capabilities, the secondary loss of the morphological modifications associated with adhesion has been reported for several lineages. The Pachydactylus clade exhibits two unequivocal losses of the adhesive apparatus (Chondrodactylus angulifer and Pachydactylus rangei), and several other reductions (e.g. Rhoptropus afer and Colopus wahlbergii). This clade occupies both sandy and rocky habitats in southern Africa, and the secondary loss (or reduction) of adhesion appears linked to shifts in habitat use, from climbing to ground dwelling. Although the gain and loss of adhesion has been documented, little is known of the resulting functional consequences. Utilizing 25 species from the Pachydactylus clade, we examined the morphometric changes associated with the reduction and loss of adhesion. We also explored the three-dimensional hindlimb kinematics of pad-bearing and secondarily padless taxa (14 species), using high speed videography, to determine the functional consequences of the reduction and loss of the adhesive apparatus. To examine morphology and kinematics in a phylogenetic framework, we developed trees based on existing sequences from four genes. We then used both Brownian motion and Ornstein–Uhlenbeck models of character evolution to compare changes in the evolutionarily rates and lability of locomotory traits in clades where adhesion is retained versus in clades where adhesion is reduced and then lost. Supported by NSF IOS-1147043 (TEH) and NSERC 9745-2008 (APR).