Saturday, August 23, 2014

The identity of the long confused snake Elapotinus picteti



Top left: The snake Elapotinus pictei, Bottom left: a scan of its skull showing
 the rear fangs. Right a map of its distribution showing is association with 
rainforest. Adapted from Kucharzewski et al.
The snake Elapotinus picteti Jan, 1862 has been an enigma, it was described without locality data. The genus and species were both based on the holotype and the species was considered to belong to the venomous African Aparallactinae (family Lamprophiidae) for more than a century. However, the snake was never re-discovered but it was accepted as a valid species until present.

Christoph Kucharzewski of the Museum für Naturkunde’s Leibniz-Institut für Evolutions- und Biodiversitätsforschung in Berlin, Germany and colleagues (2014) have now clarified the taxonomic
status of E. picteti.

The authors compared its characters the literature and identification keys for the snakes across the globe. A literature survey and subsequent study of type specimens revealed that the monotypic Elapotinus is a subjective senior synonym of the monotypic Malagasy pseudoxyrhophiine snake genus Exallodontophis Cadle, 1999, a snake characterized by its unique aglyphous dentition.

Elapotinus picteti is an amazing example how missing locality data, erroneous assumptions and character descriptions can combine and lead to misleading conclusions. Elapotinus was a problematic from the beginning and this in part explains why it took more than 150 years to unravel this taxonomic mystery.

First, there was no type locality given in the original description and the species resembles snakes that evolved convergently in Africa, Madagascar, and South America. Boulenger suggested tropical Africa as possible locality, eighty years later Mahnert suggested a Neotropical origin.
Second, there was uncertainty and confusion concerning the dentition of the species. Jan (1862a, b) described the maxillary teeth of his Elapotinus picteti as ungrooved and the teeth position similarly to Amblyodipsas. Without examination of the type material Boulenger (1896) decided to list the species within the opisthoglyphous Dipsadomorphinae and related to the African Aparallactinae and the Neotropical Elapomorphini. The error regarding dentition introduced by Boulenger led subsequent authors to list the species in the Aparallactinae as part of the family Lamprophiidae from continental Africa.

The authors transfer Elapotinus from the lamprophiid subfamily Aparallactinae to the subfamily Pseudoxyrhophiinae. Furthermore, Elapotinus picteti strongly resembles the Malagasy species Exallodontophis albignaci (Domergue, 1984) in external morphology, coloration and dentition. As a consequence we consider Elapotinus picteti a subjective senior synonym of Exallodontophis albignaci.

Citation

Kucharzewski, C, et al. 2014. A taxonomic mystery for more than 150 years: Identity, systematic position and Malagasy origin of the snake Elapotinus picteti Jan, 1862, and synonymy of Exallodontophis Cadle, 1999 (Serpentes: Lamprophiidae). Zootaxa 3852.2 (2014): 179-202.

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