What, if anything, is a ‘typical’ viper? Biological attributes of basal viperid snakes (genus Causus Wagler, 1830)
Abstract:For many major phylogenetic radiations of organisms, the available ecological knowledge is disproportionately derived from a small minority of taxa, and sometimes from organisms that are highly atypical. Viperid snakes provide a good example of this situation; high-latitude cold-climate taxa in northern Europe (vipers) and North America (rattlesnakes) have been studied intensively, but more speciose radiations in tropical Africa, Asia, and Central America remain poorly known. We dissected > 500 specimens (six species) of night adders (genus Causus), mostly from Cameroon (68%) in equatorial Africa, to quantify morphology, diets, and reproductive biology. By contrast to the ‘slow’ life-histories of cold-climate viperids, night adders feed frequently on frogs (rather than infrequently on mammals), and produce frequent large clutches of relatively small eggs (rather than infrequent small litters of relatively large live young). Thus, putatively ‘typical’ viperid attributes such as low fecundity, viviparity, and predation on mammals reflect adaptations to the invasion of cold environments by a small and perhaps atypical subset of viperid taxa. Our data on prey size suggest that one of the critical innovations of early viperids may have been an ability to subdue and ingest relatively large prey. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 575–588.
Document Type: Research Article
Affiliations: 1: Muséum national d’Histoire naturelle, Département de Systématique et Evolution (Reptiles), USM 602, Case courrier 30, 75231 Paris, Cedex 05, France 2: Biological Sciences A08, University of Sydney, New South Wales 2006, Australia 3: John Hopkins Cameroon Program CRESAR, Carrefour Intendance, BP 7039, Yaoundé, Cameroun
Publication date: December 1, 2006