Paleoclimatic models suggested a high instability of the range of this lineage in the last 3 Mya, with niche contractions during the colder glacial periods and expansions following the glacier retreat. This suggested an allopatric diversification process, with subspecies boundaries upon secondary contact maintained by competitive interactions, at least between closely related pairs. The great mountain systems of the Mediterranean Peninsulas constituted stable refugia during the Pliocene–Pleistocene cycles, favouring the evolution of endemic subclades.  Leer más.