Tuesday, July 22, 2014

[Herpetology • 2009] Thamnosophis mavotenda • Phylogenetic Relationships of A New Species of pseudoxyrhophiine Snake (Reptilia: Lamprophiidae) Suggest A Biogeographical Link Between western and northern Madagascar

Thamnosophis mavotenda
Glaw, Nagy, Köhler, Franzen & Vences, 2009

We describe a new species of the pseudoxyrhophiine snake genus Thamnosophis from a dry forest of the karstic massif Tsingy de Bemaraha in central western Madagascar. Thamnosophis mavotenda sp. n. is characterised by 19 dorsal scale rows, 188 ventrals, 110 subcaudals, and by colouration (e.g. yellow head sides). Morphological and molecular phylogenetic data indicate that the species is most closely related to the recently described Thamnosophis martae from the far north of the island which inhabits dry karstic forest and subhumid lowland rainforest. This species pair represents a well-supported example of a sister-group relationship in snakes between northern Madagascar and the Tsingy de Bemaraha plateau, and corroborates preliminary observations in other reptile species. We discuss this finding in the light of recent hypotheses on the biogeographic zonation of Madagascar.

Keywords: Serpentes; Pseudoxyrhophiinae; Thamnosophis; New species; Madagascar; Biogeography

Etymology: The specific epithet is derived from the Malagasy words “mavo” (yellow) and “tenda” (throat) and refers to the yellow throat of the holotype. It is to be treated as a noun in apposition for the purposes of nomenclature.

Distribution and Conservation: Thamnosophis mavotenda is only known from a single individual captured in the Tsingy de Bemaraha National Park. Thus, any statements on the species’ distribution and conservation status must remain tentative. Several Malagasy reptile and amphibian species are known only from this nature reserve (e.g. Schimmenti and Jesu 1996; Puente et al. 2005; Glaw et al. 2007a; Köhler et al. 2007), suggesting its importance as a center of endemism. It is therefore possible that T. mavotenda is endemic to the Tsingy de Bemaraha as well. We did not notice any obvious threat to the species, and its occurrence in a relatively large, protected area seems to indicate that it is not severely threatened, although it is remarkable that intensive surveys in this park (Bora et al. in press) did not reveal further specimens. Using the same rationale and IUCN criteria as applied during the Global Amphibian Assessment for Malagasy amphibians (Andreone et al. 2005), we classify T. mavotenda as “Data Deficient”. [>> Near Threatened (IUCNRedlist.org)]

 F. Glaw, Z.T. Nagy, J. Koehler, M. Franzen and M. Vences. 2009. Phylogenetic Relationships of A New Species of pseudoxyrhophiine Snake (Reptilia: Lamprophiidae: Thamnosophis) Suggest A Biogeographical Link Between western and northern Madagascar. Organisms, Diversity & Evolution 9:13-22.