ANTILLEAN BOTHROPS 



105 



B. lanceolatus has higher ventral and dorsal scale row counts than 

 practically all populations of the B. jararacussu-punctatus-atrox 

 clade. This suggests that the extreme scale counts found in B. 

 lanceolatus represent an autapomorphy compared to B. caribbaeus 

 and mainland Bothrops. This makes a hypothesis of dispersal from 

 the mainland to St. Lucia, and then a further dispersal event to 

 Martinique, more parsimonious than dispersal to Martinique 

 followed by further dispersal to St. Lucia. Since St. Lucia lies 

 between South America and Martinique, this scenario is also more 

 geographically parsimonious than the alternative. The slightly 

 greater length of the branch leading to B. lanceolatus is also consist- 

 ent with this hypothesis (De Salle & Templeton, 1 988; Thorpe etai, 

 1994). 



An understanding of the phylogenetic position of Bothrops 

 caribbaeus and B. lanceolatus may also have implications for their 

 venom composition and the treatment of snakebite in the Caribbean. 

 Bothrops lanceolatus envenoming has been documented to produce 

 a unique syndrome different from that of other species of Bothrops. 

 In addition to local symptoms such as pain, swelling, bleeding at the 

 site of the bite, ecchymosis and necrosis, which are common to most 

 crotaline envenomings, the systemic bothropic syndrome observed 

 in Central and South America is characterised by the development of 

 consumption coagulopathies and spontaneous systemic bleeding, 

 depending on venom components which affect clotting factors as 

 well as haemorrhagins which damage vascular endotheliums 

 (Barrantes et al, 1985; Kamiguti et al, 1991). On the other hand, 

 apart from similar local signs, the severity of systemic envenoming 

 by Bothrops lanceolatus in Martinique was correlated with the 

 development of multiple cerebral infarctions and/or other major 

 vessel occlusion that may appear within 8 hours to 7 days after the 

 bite in approximately 30 to 40% of cases (Thomas etal, 1995, 1998). 

 Infarctions can develop in patients who present initially with signs 

 of moderate envenoming with normal blood clotting and low serum 

 levels of venom antigens. The infarction process can involve several 

 small vascular territories altogether, and is associated with the 

 development of an isolated thrombocytopenia. Bogarin(V«/. ( 1999) 

 demonstrated that Bothrops lanceolatus venom, obtained from 20 

 specimens collected at different locations in Martinique, is devoid of 

 thrombin-like enzymes and of in vitro coagulant and defibrinating 

 activities, and is not coagulant when added to human citrated 

 plasma, even at concentration as high as 100 ug/mL. These data 

 suggest that thromboses observed in human B. lanceolatus enven- 

 oming result from a toxin-linked vasculitis process rather than from 

 a systemic procoagulant effect. However, the exact fhrombogenic 

 mechanism responsible for these thromboses remains unexplained. 



The monophy ly of Bothrops lanceolatus and B. caribbaeus leads to 

 the prediction that these snakes may share venom properties, which 

 may in turn be of importance for the treatment of patients bitten by 

 these snakes. In particular, do bites by B. caribbaeus result in a similar 

 thrombotic syndrome as observed in B. lanceolatus? Bothrops 

 caribbaeus envenoming was poorly documented until now. However, 

 the case of a 32 year old man who was bitten in Saint Lucia and who 

 subsequently developed multiple cerebral infarctions in the anterior 

 and posterior cerebral artery territories was recently published (Nu- 

 meric et al, 2002). The clinical presentation of this patient was 

 identical to that of patients bitten by Bothrops lanceolatus. Thus, 

 envenomings from these two species develop a unique systemic 

 thrombotic syndrome, which differs fundamentally from the defibri- 

 nation and bleeding syndrome that characterizes all other Bothrops 

 asper-atrox complex envenomations. This example suggests that, at 

 least in some cases, an understanding of the phylogeny of medically 

 important snakes can help predict the syndrome of envenoming to be 

 expected from a hitherto undocumented species. 



Our results also have implications for the conservation of the 

 Antillean Bothrops. Our data show that both B. caribbaeus and B. 

 lanceolatus represent relatively old, independent evolutionary line- 

 ages, and not recent offshoots of widespread South American taxa. 

 Conservation policy on their respective islands needs to take this into 

 account. Although Lazell (1964) described both B. lanceolatus and 

 especially B. caribbaeus as common (and Dowling, 1965, reported 

 similar experiences for the latter), more recent workers have reported 

 these snakes to be harder to find (Powell & Wittenberg, 1998). These 

 observations indicate that B. caribbaeus and B. lanceolatus may have 

 suffered a decline in population numbers over the last few decades, and 

 that a reassessment of their conservation status should be a priority. 



Finally, this paper also represents an opportunity to clarify some 

 confusion surrounding the nomenclature and synonymy of the 

 Caribbean Bothrops. As noted by Hoge & Romano Hoge (1978/79) 

 and subsequent authors, the St. Lucian lancehead was described 

 under several different names by Gray (1842). Species of Bothrops 

 described by Gray ( 1 842) include B. cinereus ('America'), B. sabinii 

 ('Demerara'). and B. subscutatus ('Demerara'). Gray (1849) also 

 described B. affinis ('Demerara' and 'Berbice'). 



The types of B. sabinii and B. subscutatus were the specimens 

 collected by Capt. (later Col.) Sabine discussed by Underwood 

 (1993), and are unquestionably assignable to B. caribbaeus 

 (Underwood, 1993; pers. obs.), of which the names B. subscutatus 

 and B. sabinii therefore represent senior synonyms. However, the 

 precedence of Garman's well-established name B. caribbaeus over 

 Gray's disused names was formally established by Wuster (2000). 



The female type specimen of Bothrops cinereus, considered incertae 

 sedis by Peters & Orejas-Miranda (1970) and conspecific with B. 

 caribbaeus by Hoge & Romano Hoge (1978/79) and Powell & 

 Wittenberg (1998), has 31 scale rows at midbody and 224 ventral 

 scales. These counts are consistent with B. lanceolatus, but not with B. 

 caribbaeus; B. cinereus is thus a junior synonym of B. lanceolatus. 

 The sy ntypes of B. affinis are assignable to B. atrox. and are consistent 

 with Guyanan populations of that species based on both scalation (24- 

 27 dorsal scale rows, 1 89-200 ventrals) and colour pattern. 



Acknowledgements. We thank A. Malhotra, N.C. Giannasi and A. 

 Tanasi (Office National des Forets de la Martinique) for help with sample 

 acquisition, and C.J. McCarthy for access to the types of Gray's species of 

 Bothrops. Finally, Garth Underwood provided enlightening information on 

 Capt. Sabine's specimens, as well as being an inexhaustible font of knowledge 

 on taxonomic matters of all kinds over many years. This study was funded by 

 the Wellcome Trust (Research Career Development Fellowship to WW. and 

 grant 057257//Z/99/Z), the EU (contracts TS3-CT9 1-0024 and IC1 8-CT96- 

 0032), Fundacao Banco do Brasil, Fundacao de Amparo a Pesquisa do 

 Estado de Sao Paulo (FAPESP) (grants 95/90 56-9, 97/2445-5 and 00/0 1 850- 

 8), and the British Council (fellowship to MGS). 



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