The persistence of marked phenotypic variation within species is evolutionarily puzzling. We uncovered remarkable variation in throat colouration in a high-altitude gecko (Atlas Day Gecko, Quedenfeldtia trachyblepharus) endemic to the High Atlas Mountains of Morocco. Orange, yellow, and white variants were found in approximately equal proportions in both sexes, and in juveniles and adults. The colour variants did not differ in body size or in body condition, but there was some indication that orange males have relatively longer jaws than white or yellow males. The number of mites harboured by an individual was not a function of its sex or of its throat colouration, but larger lizards did harbour more mites. Our data do not support the hypotheses that throat colour variation is due to selection pressures differing between the sexes or through ontogeny, or signals immunocompetence, but offer some support for the hypothesis that throat colour variation signals dominance. Future investigations on the evolution of throat colour variation in this species should use spectrophotometry to obtain finer colour classification and incorporate measures of fitness.
Gabriel Blouin-Demers, Olivier Lourdais, Abdellah Bouazza, Catherine Verreault, Hassan El Mouden and Tahar Slimani
Aziza Lansari, Miguel Vences, Susanne Hauswaldt, Ralf Hendrix, David Donaire, Abdellah Bouazza, Ulrich Joger, El Hassan El Mouden and Tahar Slimani
We assessed the genetic variation of 47 Moroccan populations of the North African water frog (Pelophylax saharicus) using partial sequences of the mitochondrial cytochrome oxidase subunit I gene (COI). All 239 samples belonged to the main haplotype clade previously identified from Morocco, with no haplotypes of the Algerian/Tunisian clades among our samples. Altogether 40 haplotypes were found, with a maximum of 13 mutational steps between them. Two weakly divergent haplogroups separated by a minimum of six mutational steps were distributed (i) in the Anti-Atlas and the Sahara (south of the High Atlas Mountains) versus (ii) in the Middle Atlas, the High Atlas, and in the Rif area north of the Atlas Massif. Haplotypes of the northern haplogroup were found at the southernmost locality, which might be due to human translocation, and co-occurrence of the two haplogroups was recorded at three sites within the range of the northern haplogroup.
Miguel Vences, Philip de Pous, Violaine Nicolas, Jesús Díaz-Rodríguez, David Donaire, Karen Hugemann, J. Susanne Hauswaldt, Felix Amat, Juan A.M. Barnestein, Sergé Bogaerts, Abdellah Bouazza, Salvador Carranza, Pedro Galán, Juan Pablo González de la Vega, Ulrich Joger, Aziza Lansari, El Hassan El Mouden, Annemarie Ohler, Delfi Sanuy, Tahar Slimani and Miguel Tejedo
Painted frogs (Discoglossus) contain five to six species of Western Palearctic anurans that are mainly distributed in allopatry. We here provide the first comprehensive assessment of the phylogeography of the Moroccan species D. scovazzi and geographically characterize its contact zone with D. pictus in Eastern Morocco. Discoglossus scovazzi shows, in general, a weak phylogeographic structure across Morocco on the basis of mitochondrial DNA sequences of the cytochrome b gene, with only populations centered in the Atlas Mountains characterized by the presence of slightly divergent haplotypes. In eastern Morocco, all populations east of the Moulouya River were clearly assignable to D. pictus. This species was also found along the Mediterranean coast west of the Moulouya, in the cities of Nador and Melilla, suggesting that not the river itself but the wide arid valley extending along much of the river (except close to the estuary) acts as a possible distributional barrier to these frogs. No sympatry of D. scovazzi with D. pictus was observed, and all specimens were concordantly assigned to either species by DNA sequences of cytochrome b and of the nuclear marker RAG1. Species distribution models of the two taxa show largely overlapping areas of suitable habitat, and the two species’ niches are significantly more similar than would be expected given the underlying environmental differences between the regions in which they occur. Comparative data are also presented from the southern Iberian contact zone of D. galganoi galganoi and D. g. jeanneae. These taxa showed less clear-cut distributional borders, extensively shared RAG1 haplotypes, and had instances of sympatric occurrence on the basis of cytochrome b haplotypes, in agreement with the hypothesis of a yet incomplete speciation. In this wide contact zone area we found mitochondrial sequences containing double peaks in electropherograms, suggesting nuclear pseudogenes or (less likely) heteroplasmy, possibly related to the ongoing admixture among the lineages.