Phylogeny and biogeography of midwife toads (Alytes, Discoglossidae): a reappraisal

Abstract

The allozyme data base of Arntzen & García-París (1995) on midwife toads (Alytes, Discoglossidae) is reanalysed considering each locus as a discrete character. The phylogeny thus inferred differs from the one obtained with genetic distances in the position of A. dickhilleni from the Betic region – it appears that its sister species is the widespread A. obstetricans, not the Mallorcan endemic A. muletensis. This phylogenetic hypothesis agrees with the taxonomic treatment of the genus based on morphology. A testable biogeographic hypothesis is proposed to account for the diversification of midwife toads in Iberia and the Balearics. The postulated underlying geological changes were the spread of inland saline lakes that divided Iberia (16 mY B.P.), the emergence and break-up of the Betic orogen (14 mY), and the formation of the Betic Strait (8 mY). Dispersal over sea channels or during the Messinian Crisis (6 mY) are deemed unlikely on the basis of ecological and biogeographical data.

Salamandra salamandra (Amphibia: Caudata: Salamandridae) in Portugal: not all black and yellow

“…Presently, Iberia is the most amphibian species-rich region in Europe (Martínez-Solano et al 2005) with eight endemic species among twenty-eight native ones (Gómez and Lunt 2007). As mentioned above, the tectonic events occurring in the Iberian Peninsula during the Miocene shaped its oragraphy and current river basins (Altaba 1997). It is not therefore unexpected, that several species have emerged at the end of this period during the Betic and Messinian crisis.…”

“…3). During this timeframe, the tectonic activity in the Iberian Peninsula led to the drainage of most river systems to a large number of lacustrine endorheic (closed) basins in central Iberia (Altaba 1997;Calvo et al 1993). These events lead to vicariant speciation in a large group of animals including e.g., midwife toads ) and freshwater snails (Altaba 1998).…”

Evidence for reticulate palaeogeography: beetle diversity linked to connection‐disjunction cycles of the Gibraltar strait

“…4; ≈ 20 My bp ; Roca, 1992). Alternatively, vicariance between north‐east and south‐west Iberia could be explained by the occurrence of inland saline lakes ( Altaba, 1997). Altaba (1997) suggests also the existence of a temporary connection between SE Iberia and the Balearics at about ≈ 15 My bp .…”

“…7; ≈ 10–5 My bp ). Alternatively, the existence of a sea channel connecting the Atlantic and the Mediterranean across the current Betic depression has been postulated ( Ziegler, 1987; Altaba, 1997).…”

“…The distributional pattern of this species (currently found at the border between LIT and ALM) cannot be explained by a vicariance event linked to the rise of the Cordillera Ibérica. The occurrence of Iberian inland saline lakes at about 16 My bp ( Altaba, 1997) could be the most likely vicariance event explaining this speciation event.…”