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Bull. not. Hist. Mus. hand. (Zool.) 68(2): 101-106 



Issued 28 November 2002 



Origin and phylogenetic position of the Lesser 

 Antillean species of Bothrops (Serpentes, 

 Viperidae): biogeographical and medical 

 implications 



WOLFGANG WUSTER AND ROGER S. THORPE 



School of Biological Sciences, University of Wales, Bangor LL57 2UW, UK 



MARIA DA GRACA SALOMAO 



Laboratorio de Herpetologia, Instituto Butantan, Av. Vital Brazil 1500, 05503-900 Sao Paulo-SP, Brazil 



LAURENT THOMAS 



Service des Urgences, CHRU, 97200 Fort de France, Martinique (French West Indies) 



GIUSEPPE PUORTO 



Museu Biologico, Instituto Butantan, Av. Vital Brazil 1500, 05503-900 Sao Paulo-SP, Brazil 



R. DAVID G. THEAKSTON 



Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK 



DAVID A. WARRELL 



Centre for Tropical Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford 0X3 9DU, 

 UK 



SYNOPSIS. We use mitochondrial DNA sequences to infer the origin and phylogenetic position of the Lesser Antillean species 

 of the pitviper genus Bothrops, B. carihbaeus and B. lanceolatus. The two species form a monophyletic group, which in turn forms 

 the sister clade to the Bothrops asper-atrox complex. High levels of sequence divergence among the Caribbean species, and 

 between them and the nearest mainland relatives, suggest a relatively ancient origin of these snakes. The hypothesis that the 

 Lesser Antillean Bothrops are the result of a recent colonisation event from within the South American B. atrox complex is 

 rejected, as is the hypothesis that they were introduced to their island habitats by aboriginal humans. The high level of 

 morphological apomorphy displayed by B. lanceolatus suggests a stepping-stone colonisation, St. Lucia being colonised first and 

 then Martinique from St. Lucia. The medical implications of these findings are discussed: a recent case of envenoming from Saint 

 Lucia suggests that Bothrops caribbaeus causes the same thrombotic syndrome of envenoming as B. lanceolatus. 



INTRODUCTION 



The genus Bothrops Wagler, 1824 contains most of the pitviper 

 fauna of South America. The genus (including the arboreal species 

 sometimes assigned to Bothriopsis) contains approximately 36 

 species, with a wider variety of body shapes and natural history traits 

 than in any other New World pitviper genus. This greater diversity 

 has been ascribed to the fact that Bothrops was the first group of 

 pitvipers to reach the South American continent, thus giving ample 

 opportunity for adaptive radiation (Wiister et al, in press). 



Two species of Bothrops occur in the Lesser Antilles: Bothrops 

 caribbaeus (Garman, 1887) on St. Lucia, and Bothrops lanceolatus 

 (Lacepede, 1789) on Martinique. The status and origin of these 

 forms has been the subject of much debate. Long considered to be 

 conspecific with Bothrops atrox, B. lanceolatus was revalidated by 

 Hoge (1952), and the validity of B. lanceolatus and B. caribbaeus 

 confirmed by Lazell (1964). This latter interpretation has been 

 followed by most authors since then (e.g., Campbell & Lamar, 

 1 989). However, Sandner Montilla (1981,1 990) regarded the Lesser 

 Antillean Bothrops as conspecific with each other, as well as with 

 mainland Bothrops asper and the northern Venezuelan populations 

 of the B. asper-atrox complex. 



The origin of the Antillean Bothrops has been the subject of much 

 speculation and mythology. This includes popular tales that the 



snakes were originally introduced by Carib Indians in their attempts 

 to gain control of the islands from resident Arawaks (Dowling, 

 1965), and the notion that dispersal from the South American 

 mainland is common and ongoing (Sandner Montilla, 1981). 



The reptile fauna of the Lesser Antilles is primarily the result of 

 long-distance dispersal by individual species, as these islands have 

 not been linked to the South American mainland or any other 

 landmass at any time in their history (Thorpe et al, in press; 

 Malhotra and Thorpe 1 999). This means that some species present in 

 these islands represent long-standing endemic lineages (Thorpe et 

 al., in press; Malhotra and Thorpe 2000), whereas others appear to 

 be the result of relatively recent dispersal events from well-defined 

 source populations or taxa in South America, as is the case for the 

 genus Corallus (Henderson & Hedges, 1995). 



Compared to morphological data, molecular markers such as 

 mitochondrial DNA (mtDNA) sequence data have the advantage 

 that they can give an estimate of phylogeny reasonably free of the 

 confounding effects of differing natural selection pressures on the 

 external phenotype. Moreover, molecular sequence data also have 

 the advantage that they can give at least an approximate estimate of 

 times of divergence between lineages, although the interpretation of 

 molecular clocks is subject to various analytical and empirical 

 problems (Hillis et al, 1996). 



Several recent mtDNA-based phylogenetic analyses of the genus 

 Bothrops have included the Antillean species. Salomao et al. (1997, 



) The Natural History Museum, 2002 



