Phylogenetic affinities of the fossil elapids Naja romani and Naja antiqua (Serpentes: Elapidae)
Abstract
The genus Naja Laurenti, 1768 comprises 32 extant species of venomous
snakes, commonly known as "cobras", allocated in four distinct lineages
(Wüster et al., 2007, Mol. Phyl. Evol. 45:437–453): the Asian
spitting-cobras (11 species, subgenus Naja), the African spittingcobras
(seven species, subgenus Afronaja), the African non-spitting
open area clade (six species, subgenus Uraeus) and the African nonspitting
forest clade (seven species, subgenus Boulengerina). In recent
years, the diversity of the genus has grown considerably, mainly given
to taxonomic revisions based on new molecular analyses and new discoveries
in the field. Furthermore, while the taxonomy of the genus is
now considered stable, its evolutionary history remains poorly understood,
especially within the known lineages. Apart from the extant
species, the genus Naja also presents a rich fossil record that spans
from the Early/Middle Miocene to the Late Pliocene in Africa and
Europe. This fossil record has been studied in the past, with important
remarks on their distribution throughout the European continent
(Bachmayer, F. & Szyndlar, Z., 1985, Ann. Naturhist. Mus. Wien,
87:79–100; Szyndlar, Z. & Rage, J. C., 1990, Amphibia-Reptilia
11:385–400; Szyndlar, Z. & Zerova, G. A., 1990, Ann. Naturhist.
Mus. Wien 91A:53–61). Szyndlar & Rage (1990) provided an osteological
description of the genus based on both extant and extinct species,
in an important contribution showing their geographic distribution.
However, no attempts have been made to conduct a broader phylogenetic
analysis until then. Here, we present the first attempt to elucidate
the phylogenetic history of the genus, with a morphological analysis
that includes 26 of the 32 extant species along with key-fossil taxa
from the Miocene Naja antiqua and Naja romani) and the Pliocene
(Naja depereti).