10.1016/j.ympev.2006.03.028
https://zenodo.org/records/895053
oai:zenodo.org:895053
Carranza, S.
S.
Carranza
Arnold, E. N.
E. N.
Arnold
Pleguezuelos, J. M.
J. M.
Pleguezuelos
Phylogeny, biogeography, and evolution of two Mediterranean snakes, Malpolon monspessulanus and Hemorrhois hippocrepis (Squamata, Colubridae), using mtDNA sequences
Zenodo
2006
2006-08-01
Other (Open)
Variation in 815 bp of mitochondrial DNA from two gene fragments (300 bp of cytochrome b and 395–515 bp of 12S rRNA) for 26
Malpolon monspessulanus, and cytochrome b for a further 21 individuals, indicates that this species originated in the Maghreb area of
Northwest Africa. Here, an estimated 3.5–6 Mya, it divided into the western M. m. monspessulanus, and an eastern clade including
M. m. insignitus and M. m. fuscus. The very limited genetic differentiation between Maghreb and Southwest European populations of
this form suggests that it arrived in the Iberian Peninsula only recently. Population genetics and demographic tests indicate subsequent
expansion in this area around 83,000–168,000 year ago. Because present populations of Malpolon arrived recently, mid-Pliocene and at
least some Pleistocene fossils of the genus Malpolon in Southwest Europe are probably derived from an earlier invasion from the Maghreb,
possibly as early as the end of the Miocene period, 5.3–5.9 Mya, when there was a temporary land bridge across the site of the Strait
of Gibraltar and the Mediterranean Sea desiccated. The descendants of this earlier invasion must have eventually become extinct, perhaps
during one of the Pleistocene glaciations. In contrast to the western M. m. monspessulanus, the greater genetic divergence found in
the eastern clade of M. monspessulanus suggests that it dispersed at an earlier date and probably over a longer period, spreading eastwards
through northern Libya and Egypt to Syria, Iraq, and Iran, and around the Mediterranean Sea through Turkey into the Aegean
archipelagos and the Balkan peninsula. The western and eastern units of M. monspessulanus have different dorsal color pattern, differences
in skull structure and exhibit an 8.4% uncorrected genetic divergence in the combined gene fragments investigated here. It is consequently
recommended that they should be treated as separate species: M. monspessulanus (sensu stricto) and Malpolon insignitus stat.
nov., the latter including the subspecies Malpolon insignitus fuscus comb. nov. The same combined mitochondrial gene fragments used in
Malpolon were investigated in 20 individuals of Hemorrhois hippocrepis, and of cytochrome b alone in a further 17. They indicate that this
species also originated in the Maghreb and again invaded the Iberian Peninsula quite recently. Some of the most recent invasions of the
Iberian Peninsula by reptiles and amphibian taxa could probably be anthropogenic in origin. Some other species including M. monspessulanus
and H. hippocrepis, may have crossed naturally, by 'hopping' across the Strait of Gibraltar via temporary islands on the
shallowest parts that were exposed during sea-level fall associated with Pleistocene glaciations.