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  • Author or Editor: Miguel Carretero x
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In: Amphibia-Reptilia

Abstract

The evolutionary relationships of amphisbaenians of the genus Blanus have long been controversial. Presently two species are recognized for Morocco — Blanus tingitanus and B. mettetali and one for Iberia — B. cinereus. Using mitochondrial and nuclear DNA sequences, 25 samples from Portugal, Spain and Morocco were analysed. Both markers indicate the existence of three well-separated clades: one for the Northern Moroccan samples, corresponding to B. tingitanus and two to the B. cinereus samples. One sample from Taza, Morocco, was identical to specimens from one of the Iberian forms. These results point to the necessity of a systematic revision. These new groups reinforce the need for geographically broader sampling accompanied by morphological studies to fully determine the phylogenetic history of this species complex.

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In: Amphibia-Reptilia

Abstract

Growth ring counts on the shell have been widely used for age estimation in Chelonians. However, as stated by Wilson et al. (2003), most studies have applied this method without assessing its reliability by proving that 1 : 1 ratio between number of rings and real age exists. In the present study, the reliability of this method is analysed for a population of Hermann's Tortoise, Testudo hermanni introduced in the Ebro Delta (NE Spain). Age estimations were obtained from direct observations of tortoises in the field in 2000 (n = 82) together with those from photographs of the same and other individuals of the population taken between 1991 and 2001 (n= 356). A second photograph was taken at one or more years after the first one for 101 individuals. Results of Model II linear regression analysis indicated that the method was reliable only for tortoises between 0 and 7 years old, whereas tended to underestimate age for those between 8 and 11 years. Since, sexual maturity in this population is attained around 8 years (mean for both sexes), ring counts are only reliable for juveniles and subadults. Finally, it is noteworthy that the results coming for photographs were equivalent to those coming from direct observations in the field.

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In: Amphibia-Reptilia

Abstract

Morphometric analyses were carried out on Testudo graeca from west-central Morocco, and compared to previously published mitochondrial DNA sequence variation. We measured 41 characters on 244 tortoises from three localities, including one population of T. g. soussensis from Souss Valley. All three populations could be statistically differentiated in a multivariate space using these characters. The population from the Jbilet mountains was the most differentiated (no overlap), those from Essaouira on the coast and from Admine showed limited overlap (5%). Sexual size dimorphism (males < females) remained constant between sites. Sexual shape dimorphism was prominent in all populations, but the degree of dimorphism differed for some characters when corrected for size. Tortoises from Jbilet living under harsher conditions (low precipitation, high thermal amplitude, low plant cover) were smaller, lighter, more flattened and less dimorphic in shape than the others. Although the Admine population (currently assigned to T. g. soussensis) was morphologically distinct, its distinctiveness was less supported than in the case of Jbilet; several other qualitative traits previously considered as defining this subspecies were also questionable. Moreover, this morphological variation contrasted with the available genetic evidence (12S rRNA mtDNA) which did not reveal significant variation between any of the populations. This implies that morphological differences have either arisen very recently or can be attributed to phenotypic plasticity. This should be taken into account when using morphological traits for taxonomic considerations and conservation management.

In: Animal Biology

Abstract

Podarcis bocagei and P. carbonelli are two closely related lizard species, endemic to the western Iberian Peninsula. Although genetic and morphological distinction between them is now well established, information on anatomical features is still very restricted. We studied presacral vertebrae number in both species, separately examining cervical and trunk vertebrae counts, in order to assess the interspecific and intersexual variation in these characters. There was no significant interspecific variation among lizards of the same sex for any of the vertebrae counts studied. However, important sexual variation existed, females presenting higher counts than males for both trunk and total presacral vertebrae, while males showed higher values of cervical vertebrae. Although our results lie within the known limits for other closely related species, they reveal that vertebrae number might present higher intraspecific variation than previously thought.

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In: Amphibia-Reptilia

Abstract

Western Indian Ocean islands (excluding Madagascar) are inhabited by at least five species of the lizard genus Mabuya, for which diversity and inter-island phylogenetic relationships are still unclear, particularly concerning island populations of M. maculilabris, M. comorensis and M. striata. With a comprehensive sampling across the Comoros archipelago and the islands of Zanzibar and Pemba (Tanzania) we use molecular data and previously published sequences of these species to describe genetic variation across their insular range and explore the possible distinction of insular populations of the different species, contributing to the clarification of their status and knowledge of their colonization patterns. We describe patterns of cryptic diversity within M. comorensis, revealing a West to East colonization of the Comoros archipelago and clarify the status of Malagasy populations of this species. Cryptic variation is also observed within M. maculilabris and M. striata, and the status of several continental and island populations discussed. M. sechellensis is shown to be paraphyletic relative to M. wrightii. Available data for all Afro-Malagasy Mabuya reveals additional possible instances of paraphyly within some species but does not allow for further resolution of basal relationships within this group, pointing to rapid and simultaneous divergences within this group and the need for multiple independent markers to recover the history of this group.

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In: Amphibia-Reptilia

Abstract

Preferred body temperatures (Tp) were analysed in the lacertid Podarcis vaucheri, from S. Iberia and N. Africa which has been recently revalidated as a full species within the P. hispanica complex. Adult lizards from a Moroccan population were exposed to a thermal gradient and Tp was measured at ten time intervals. Intraspecific Tp variation due to sex and reproductive condition (Tp: non-pregnant females ≥ males ≥ pregnant females) and time of the day (Tp: early morning > rest of the day) was detected. Pregnant females tended to increase their Tp after egg-laying. This dependence on the reproductive condition parallels findings in other lacertids. Class-by-class comparisons between P. vaucheri and P. (hispanica) liolepis from NE Iberia, analysed with the same methodology, revealed higher Tp values in P. vaucheri (non-pregnant females). Although further research is needed to determine the evolutionary pattern of the Tp divergence in this group, these results are compatible with the thermal rigidity hypothesis reinforcing the view of P. hispanica s.l. as an artificial assemblage.

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In: Amphibia-Reptilia
In: Amphibia-Reptilia