Evolutionary relationships among the true vipers (Reptilia : viperidae) inferred from mitochondrial DNA sequences

Nucleotide sequences of mitochondrial cytochrome b and 16S rRNA genes, tota ling 946 bp, were used to reconstruct a molecular phylogeny of 12 species o f the subfamily Viperinae representing 12 of the 13 recognized genera, Maxi mum-parsimony and maximum-likelihood mere used as methods for phylogeny rec onstruction with and without a posteriori weighting, When representatives o f the Causinae were taken as outgroup, five major monophyletic groups were consistently identified: Bitis, Cerastes, Echis, the Atherini (Atheris s,l. ), and the Eurasian viperines. Proatheris was affiliated with Atheris, and Adenorhinos clustered within Atheris, The African Bitis consisted of at lea st three monophyletic groups: iii the B. gabonica group, (ii) the B. caudal is group, and (iii) the B. cornuta group. B. worthingtoni and B. arietans a re not included in any of these lineages. Eurasian viperines could be unamb iguously devided into four monophyletic groups: (i) Pseudocerastes and Eris ticophis, (ii) European vipers (Vipera s.str,), (iii) Middle East Macrovipe ra plus Montivipera (Vipera xanthina group), and (iv) North African Macrovi pera plus Vipera palaestinae and Daboia russelii, These evolutionary lineag es are consistent with historical biogeographical patterns. According to ou r analyses, the viperines originated in the Oligocene in Africa and success ively under- went a first radiation leading to the five basal groups. The r adiation might have been driven by the possession of an effective venom app aratus and a foraging startegy (sit-wait-strike) superior in most African b iomes and might have been adaptive. The next diversifications led to the Pr oatheris-Atheris furcation, the basal Bitis splitting and the emergence of the basal lineages within the Eurasian stock. Thereafter, lineages within E chia, Atheris, and Cerastes evolved. The emergence of three groups within V ipera s.l. might have been forced by the existence of three land masses dur ing the early Miocene in the area of the Paratethys and the Mediterranean S eas. Taxonomic consequences of these findings are discussed. (C) 2001 Acade mic Press.