Potential envenomation by the aglyphous pseudoxyrhophiine snake Leioheterodon madagascariensis and description of its dentition

Abstract

We report on a case of potential envenomation caused by multiple bites by the aglyphous opisthodont snake Leioheterodon madagascariensis in the left thumb of a healthy adult man, which is among the most serious snakebites hitherto reported from Madagascar. The adult snake (total length > 1 meter) was unusually aggressive before and during capture. The symptoms included extensive bleeding, severe local pain, and substantial swelling of the hand and the distal part of the lower arm. The swelling disappeared entirely after five days, but pain in the thumb (when moved) was recognizable even longer. Although L. madagascariensis is widespread and common in anthropogenic habitats in eastern and western Madagascar, this case report seems to be the first description of long-lasting symptoms of its bite. Since aglyphous snakes are relatively rarely involved in “envenomation” and because hemolytic activity has been recorded in the secretions of the Duvernoy’s glands of Leioheterodon, we describe its dentition using microcomputed tomography and discuss the potential mode of envenomation in this case.Electronic supplementary materialThe online version of this article (doi:10.1186/s40409-015-0047-2) contains supplementary material, which is available to authorized users.

The Origins and Diversification of the Exceptionally Rich Gemsnakes (Colubroidea: Lamprophiidae: Pseudoxyrhophiinae) in Madagascar

“…Potentially related to dietary and habitat preferences, gemsnakes can be divided into aglyphous taxa without grooved rear teeth and opisthoglyphous species, which feature enlarged, grooved rear teeth used to hold or envenomate prey (Guibé 1958;Kardong 1980;Mori and Mizuta 2006;D'Cruze 2008;Weinstein et al 2011), though we note that aglyphous gemsnakes may also envenomate prey (Razafimahatratra et al 2015). While dentition and diet may be correlated (Knox and Jackson 2010), for most snakes on continental systems, it is unclear if dentition type relates to general ecological or prey preferences and if this trait is phylogenetically conserved.…”

“…Alternatively, changes in speciation rates from the Neogene to the Pleistocene may not be related to carrying capacities if: 1) rates of speciation were directly associated with environmental instability and habitats changed more rapidly in the Neogene than the Pleistocene, 2) rates were time dependent and reduced as groups fail to diversify with changing environments, or 3) where extinction rates were suitably high (Vrba 1985;Rosenzweig 1995;Pigot et al 2010;Pyron and Burbrink 2012a;Quental and Marshall 2013;Moen and Morlon 2014). This paradox, where standing diversity was most likely generated in the Pleistocene yet may also have been a period of declining diversification rates, has been addressed in other arboreal prey, such as lizards or frogs, may be required for successful capture, but we note that some aglyphous taxa have enlarged rear teeth, yet with no groove, but may still envenomate prey (Razafimahatratra et al 2015). Further work on mandibular and tooth morphology here, which includes hinged teeth, gaps in tooth rows, enlarged anterior teeth, and edentulous jaws (Savitzky 1983;Cadle 1996Cadle , 1999Cadle , 2003Cadle , 2014, integrated with prey capture, envenomation, and production or constitution of venom should be examined for a more nuanced view of gemsnake trait evolution.…”