From Europe to Africa and vice versa: evidence for multiple intercontinental dispersal in ribbed salamanders (GenusPleurodeles)

Abstract

Aim The intricate puzzle-like geography of the western Mediterranean is a product of long-term tectonic and orogenic events, supplemented by repeated climatic oscillations since the Pliocene. It offers numerous vicariance events that may be invoked to explain speciation in amphibians. We test for plausibility of two mutually exclusive Iberian-African vicariance hypotheses to explain the basal split within newts of the genus Pleurodeles: (1) the disconnection of the Betic arch c. 14 Ma and (2) the end of the Messinian salinity crisis 5.33 Ma.Location Specimens of P. waltl and P. poireti were sampled from 32 populations in Portugal, Spain, Morocco, Algeria and Tunisia.Methods Parts of three mitochondrial genes were sequenced (16S rRNA, cytochrome b, ATPase). Based on substitution rate constancy among lineages three different molecular clocks were calibrated to derive competing evolutionary scenarios for lineage evolution within Pleurodeles.Results One scenario was aligned with the dated fossil record and with historical events that are known to have enabled terrestrial faunal exchange between Europe and Africa. In Pleurodeles, such faunal exchange is more likely to have happened three times, resulting in the current pattern of species diversity and haplotype distribution: (1) following the disconnection of the Betic region from Iberia and connection of its southernmost part (present-day Rif Mountains) to Africa, c. 14 Ma; (2) closing of the Strait of Gibraltar prior to the Messinian salinity crisis, 5.59-5.33 Ma; (3) passive dispersal in recent times, caused by rafting on vegetation or inadvertent displacement by man. The results show that North African P. poireti populations comprise two distinct lineages; despite their geographical proximity, haplotype distribution within both lineages indicates totally different histories (range fragmentation vs. dispersal).Main conclusions Ribbed salamanders mainly evolved through allopatric speciation, driven by vicariance events. However, faunal exchange between Europe and Africa at the western end of the Mediterranean basin was linked to well-known events of physical contact between both continents. This sheds new light on the potential role of dispersal across marine barriers via rafting or even, presumably inadvertent, anthropogenic displacement for the initiation of speciation in amphibians.

A Bayesian approach on molecules and behavior: reconsidering phylogenetic and evolutionary patterns of the Salamandridae with emphasis on Triturus newts

“…On the other hand, our C3-C5-based estimate is 30 mya . This estimate is still compatible with one of Veith et al's (2004) calibrations (Calibration II: 23-31 mya), but it is not compatible with known fossil evidence.…”

“…Using the C2-C4 calibration the age is fixed at 44 mya because C4 is a calibration point. Interestingly, Calibration III is also the only one of the three proposed by Veith et al (2004) that is consistent with the current fossil record for Pleurodeles and Tylototriton (Chelotriton weigelti, 44 mya). On the other hand, our C3-C5-based estimate is 30 mya .…”

“…Veith et al (2004) identified three possible biogeographic scenarios that could have led to the observed phylogeographic patterns in Pleurodeles in the western Mediterranean region. These scenarios can be dated using two vicariance events involving the Iberian-African area; the disconnection of the Betic Arch, dated at ca.…”

Overlooked cryptic endemism in copepods: Systematics and natural history of the calanoid subgenus Occidodiaptomus Borutzky 1991 (Copepoda, Calanoida, Diaptomidae)

“…Such a pattern is known for other taxa (e.g. : Veith et al, 2004;Pfenninger et al, 2010) and is to be ascribed to an early separation of the Baetic-Rif area from the rest of the Iberian plate.…”

Mitochondrial DNA signatures at different spatial scales: from the effects of the Straits of Gibraltar to population structure in the meridional serotine bat (Eptesicus isabellinus)

“…mtDNA signal in E. isabellinus J Juste et al lack of differentiation between one side of the Straits of Gibraltar and the other has been found in birds (Guillaumet et al, 2006), shrews (Brändli et al, 2005), salamanders (Veith et al, 2004) and probably even in worm lizards (Vaconcelos et al, 2006). However, for the bats Myotis myotis (Castella et al, 2000), Myotis nattereri (García-Mudarra et al, 2009), Plecotus austriacus (Juste et al, 2004) and Pipistrellus pipistrellus (Hulva et al, 2004), the Straits of Gibraltar seem to be an effective barrier and to have helped in promoting or maintaining lineages that are genetically highly differentiated.…”