%0 Journal Article
%T Evolutionary morphology of the rattlesnake style
%A Jesse M Meik
%A Andr¨¦ Pires-daSilva
%J BMC Evolutionary Biology
%D 2009
%I BioMed Central
%R 10.1186/1471-2148-9-35
%X Evolutionary Principal Components Analysis revealed an inverse relationship between caudal segmental counts and style size, supporting the hypothesis that bone from caudal vertebral elements was reallocated to style formation during the evolution of this structure. Most of the basal rattlesnake species have small styles consisting of few compacted vertebral elements; however, early in the rattlesnake radiation there appears to have been two independent transitions to relatively large, pronged styles consisting of multiple coalesced vertebrae (once in Sistrurus catenatus, and once in Crotalus following the divergence of the Mexican long-tailed rattlesnakes). In terms of style shape, the two most divergent species, C. catalinensis and C. ericsmithi, provide insight into the possible relationship between style and rattle matrix morphology and lineage-specific evolutionary strategies for retaining rattle segments.The considerable interspecific variation in rattle morphology appears to correspond to variation in the bony style. We hypothesize that style morphology evolves indirectly as an integrated module responding to adaptive evolution on matrix morphology.The rattlesnake rattle is a complex aposematic sound-producing structure, composed of keratinous, multilobed, interlocking segments that is presumed to have evolved once [1,2] and as an integrated anatomical, physiological, and behavioral system is a key innovation uniting a diverse radiation of venomous New World pitvipers (genera Crotalus and Sistrurus). Aside from early embryonic and ontogenetic descriptions [e.g., [3-6]] very little is known of the development of the rattle system. Most recent studies have focused on physiological and auditory elements of the rattle [e.g., [7-9]]; the genetic basis of morphological development remains unknown. The site of actual rattle segment formation is the end-body, the living basal rattle segment that includes the style, the matrix (i.e., fibrous connective tissue that form
%U http://www.biomedcentral.com/1471-2148/9/35