A DWARF AMONG GIANTS: BIOGEOGRAPHY AND PHYLOGENETIC POSITION OF THE ELUSIVE ANGOLAN ADDER, BITIS HERALDICA (BOCAGE, 1889).

The Angolan Adder, Bitis heraldica (Bocage, 1889), endemic to the Angolan central plateau is one of the most poorly known and rarely observed species of African snakes. The phylogenetic placement of B. heraldica within the four subgenera of the genus Bitis (Bitis, Macrocerastes, Calechidna, Keniabitis) remains highly problematic. The few recent taxonomic and phylogenetic revisions dealing with African viperids and the genus Bitis have faced a complete lack of molecular data on it, and all recent authors followed the morphology-based opinion that considered B. heraldica as member of the subgenus Calechidna, due to its diminute size and similar morphology. During a survey to Huambo Province, central Angola, we collected the first specimens of this species in the last 65 years, allowing us to test its phylogenetic affinities. We generated sequence data for the species from two mitochondrial (16S, ND2) and one nuclear (PRLR) marker. To place B. heraldica in a phylogenetic context, Bayesian and maximum likelihood analyses were run. Additional data were downloaded from GenBank for individuals from all species of Bitis, with the exception of B. harenna for which no genetic data are available. Contrary to what was expected, our results unambiguously place B. heraldica among other members of the subgenus Macrocerastes, constituted by the largest members of the genus. The placement of B. heraldica within Macrocerastes raises interesting questions about body-size evolution in viperids, as well as contributes to a better understanding of the biogeographic patterns of Southwestern Africa, and especially to the increasingly known faunal-turnover in Angola. [ABSTRACT FROM AUTHOR]