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Graciá Martínez, E., Giménez, A., Anadón, J. D., Harris, J. D., Fritz, U., & Botella, F. , When did the spur-thighed tortoise colonize south-eastern spain? Unpublished paper presented at XII Congresso Luso Espanhol de Herpetologia.
Added by: Admin (06 Jan 2014 18:22:51 UTC) |
| Resource type: Conference Paper BibTeX citation key: GraciMartnez2012 View all bibliographic details  |
Categories: General Keywords: Habitat - habitat, Schildkröten - turtles + tortoises, Südwesteuropa - South-Western Europa, Testudinidae, Testudo graeca Creators: Anadón, Botella, Fritz, Giménez, Graciá Martínez, Harris Collection: XII Congresso Luso Espanhol de Herpetologia |
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Testudinidae Recent biogeographic studies have identified a North African, Late Pleistocene, origin for some species of the Iberian Peninsula. Assessment of such range expansions requires high resolution molecular tools to resolve overlapping biogeographic and cultural processes. Here we aim to determine whether the spur-thighed tortoise Testudo graeca arrived in south-eastern Spain during historic or prehistoric times, and whether its dispersal to the Iberian Peninsula was human-mediated. Using 428 samples from 19 sites in North Africa and 18 in south-eastern Spain, we obtained mitochondrial sequences from the cytochrome b gene and genotypes derived from 7 microsatellite loci. These data were employed to obtain population genetics descriptors, haplotype networks, Bayesian clusters analyses and isolationby- distance patterns. Moreover, we used a Bayesian demographic approach to delimit the dates involved in the range expansion. We found for the south-eastern Spanish tortoises lower levels of genetic variability and weak mitochondrial differentiation compared to the North African ones. However, exclusive haplotypes occur in the Iberian samples and microsatellite cluster analyses reveal moderate levels of admixture across both sides of the Mediterranean. A coastal area in the west of Algeria and the central-southern region in south-eastern Spain are suggested as the most probable founder and arrival places, respectively. Finally, we identify signatures of an ancient bottleneck event approximately 20,000- 30,000 years ago. Our results suggest that the spur-thighed tortoise probably arrived to south-eastern Spain profiting from the low sea level conditions of the Mediterranean Basin during the Late Pleistocene. However, although we were able to delimitate the frame time of the species’ arrival, the role that humans could have played as dispersers across the Mediterranean remains unclear. Our results are in accord with other recent findings of transmediterranean expansions during this period and highlight the importance of employing precise methodological approaches before a species can be considered as historically introduced.
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