36 research outputs found

    First description of a fossil chamaeleonid from Greece and its relevance for the European biogeographic history of the group

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    The fossil record of Chamaeleonidae is very scarce and any new specimen is therefore considered important for our understanding of the evolutionary and biogeographic history of the group. New specimens from the early Miocene of Aliveri (Evia Island), Greece constitute the only fossils of these lizards from southeastern Europe. Skull roofing material is tentatively attributed to the Czech species Chamaeleo cf. andrusovi, revealing a range extension for this taxon, whereas tooth-bearing elements are described as indeterminate chamaeleonids. The Aliveri fossils rank well among the oldest known reptiles from Greece, provide evidence for the dispersal routes of chameleons out of Africa towards the European continent and, additionally, imply strong affinities with coeval chamaeleonids from Central Europe

    Historical biogeography of Western Palearctic pelobatid and pelodytid frogs: a molecular phylogenetic perspective

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    Abstract Spadefoot toads (Pelobates) and Parsley frogs (Pelodytes) are an enigmatic group of Western Palaearctic anurans. In the genus Pelobates, a fossorial lifestyle has enforced a conserved bauplan that masks their intraspecific evolutionary history. We used partial sequences of the mitochondrial 16S and 12S rRNA genes to infer a paleobiogeographic scenario of speciation events in these two anuran genera. Based on two alternative, mutually exclusive calibrations of the Iberian-African split within Pelobates (Pb. cultripes and Pb. varaldii), the disjunction of the Betic Cordillera ca. 14-16 million years ago (mya), and the end of the Messinian Salinity crisis 5.33 mya, we inferred alternative scenarios for species evolution within both genera applying regression-based dating and Bayesian molecular dating. Pelobates and Pelodytes are both monophyletic genera. Interspecific relationships among spadefoot toads are poorly resolved, and only an Iberian-African Pb. cultripes/Pb. varaldii clade consistently emerges from our analyses. An evolutionary scenario based on the Messinian divergence of African and Iberian Pelobates lineages becomes plausible in the light of geological and paleontological data. Consequently, Pelobates species are likely to have originated from the Miocene. Speciation around the Oligocene/Miocene boundary is inferred for the Iberian-Caucasian Pelodytes, and a Messinian divergence has to be invoked to explain intraspecific diversification of Iberian parsley frogs. There is indication that the different Pb. syriacus lineages may not form a monophylum

    Palaeoclimatic changes explain Anatolian mountain frog evolution: a test for alternating vicariance and dispersal events

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    Holarctic biodiversity has been influenced by climatic fluctuations since the Pliocene. Asia Minor was one of the major corridors for postglacial invasions in the Palearctic. Today this area is characterized by an extraordinarily rich fauna with close affiliation to European, Asian and Indo-African biota. However, exact scenarios of range expansion and contraction are lacking. Using a phylogeographical approach we (i) identify monophyletic lineages among Anatolian mountain frogs and (ii) derive a spatio-temporal hypothesis for the invasion process in Anatolia. We sequenced 540 bp of the mitochondrial 16S rRNA gene from 40 populations of mountain frogs from Anatolia, the Elburz Mountains and the Caucasus. Our samples comprise all known species and subspecies: Rana macrocnemis macrocnemis R. m. tavasensis, R. m. pseudodalmatina, R. camerani and R. holtzi. They include the type localities of four of these taxa. We used a nested clade analysis (NCA) to infer historical and recurrent events that account for the observed geographical distribution of haplotypes. None of the extant species is monophyletic. Based on a molecular clock calibration using homologous sequences of Western Palearctic water frogs of the same genus, we estimated that a basic radiation into three lineages c. 2 Mya was followed by several dispersal and fragmentation events. The geographical distribution of resident and widespread haplotypes allows us to infer and date scenarios of range expansion and fragmentation that are aligned with dramatic climatic oscillations that have occurred during the last 600 000 years. Consequently, Pliocene and Pleistocene climatic oscillations triggered the evolution of Anatolian mountain frogs through an interplay of vicariance and dispersal events
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