Catarina Rato

Evolutionary history of the genus Tarentola (Gekkota: Phyllodactylidae) from the Mediterranean Basin, estimated using multilocus sequence data

BackgroundThe pronounced morphological conservatism within Tarentola geckos contrasted with a high genetic variation in North Africa, has led to the hypothesis that this group could represent a cryptic species complex, a challenging system to study especially when trying to define distinct evolutionary entities and address biogeographic hypotheses. In the present work we have re-examined the phylogenetic and phylogeographic relationships between and within all Mediterranean species of Tarentola, placing the genealogies obtained into a temporal framework. In order to do this, we have investigated the sequence variation of two mitochondrial (12S rRNA and 16S rRNA), and four nuclear markers (ACM4, PDC, MC1R, and RAG2) for 384 individuals of all known Mediterranean Tarentola species, so that their evolutionary history could be assessed.ResultsOf all three generated genealogies (combined mtDNA, combined nDNA, and mtDNA+nDNA) we prefer the phylogenetic relationships obtained when all genetic markers are combined. A total of 133 individuals, and 2,901 bp of sequence length, were used in this analysis. The phylogeny obtained for Tarentola presents deep branches, with T. annularis, T. ephippiata and T. chazaliae occupying a basal position and splitting from the remaining species around 15.38 Mya. Tarentola boehmei is sister to all other Mediterranean species, from which it split around 11.38 Mya. There are also two other major groups: 1) the T. mauritanica complex present in North Africa and Europe; and 2) the clade formed by the T. fascicularis/deserti complex, T. neglecta and T. mindiae, occurring only in North Africa. The cladogenesis between these two groups occurred around 8.69 Mya, coincident with the late Miocene. Contrary to what was initially proposed, T. neglecta and T. mindiae are sister taxa to both T. fascicularis and T. deserti.ConclusionsAt least in the Iberian Peninsula and Northwest Africa, the lineages obtained have some geographic coherency, whilst the evolutionary history of the forms from Northeast Africa remains unclear, with a paraphyletic T. fascicularis with respect to T. deserti. The separation between the T. mauritanica complex and the clade formed by the T. fascicularis/deserti complex, T. neglecta and T. mindiae is coincident with the uplift of the Atlas Mountain chain, and the establishment of two distinct bioclimatic regions on each side of the barrier.

Phylogeography and genetic diversity of Psammophis schokari (Serpentes) in North Africa based on mitochondrial DNA sequences

ABSTRACT The snake Psammophis schokari has a widespread distribution across North Africa, and in Morocco/Western Sahara is represented by three different morphotypes: striped, unicoloured and the Western-Sahara morph. ND4 mitochondrial DNA sequences from 28 specimens comprising 20 P. shokari, two P. aegyptius, one P. elegans, two P. sibilans, one P. condanarus and two outgroups were analysed. Within P. schokari we identified four genetic lineages (Morocco/Western Sahara, Mauritania, Algeria and Israel) with a genetic divergence ranging from 4–5%, less than that typically found between different species. Surprisingly, Moroccan/Western Sahara and Algerian lineages are the most divergent ones. This geographic substructuring may be due to severe climate changes in the Sahara desert between the Miocene and Pleistocene associated with expansion/contraction phases of this desert. Psammophis aegyptius is the sister-taxon of Psammophis schokari with a high level of genetic divergence between them (10.7%) supporting the recognition of P. aegyptius as a distinct species. The three Moroccan/Western Sahara colour morphotypes form one genetic lineage, indicating that colour pattern does not reflect a different phylogenetic history, and is probably an ecological adaptation to the local environment.

Genetic variation within Saurodactylus and its phylogenetic relationships within the Gekkonoidea estimated from mitochondrial and nuclear DNA sequences

Phylogenetic relationships of the three morphological forms within the gecko genus Saurodactylus were estimated using mtDNA (12S rRNA and ND4) sequences. High between morphological forms variation (up to 25% with ND4), confirms that all three deserve specific status. Saurodactylus mauritanicus and Saurodactylus brosseti are strongly supported as sister taxa. Our results again highlight the extremely high mtDNA variability almost universally reported from within gecko species. The position of Saurodactylus within the Gekkonoidea was also investigated. Although considered as a member of the sphaerodactyl geckos, its taxonomic position is still highly uncertain. Evaluation of C- mos nuclear DNA sequences supports many of the recent taxonomic rearrangements within the Gekkonoidea. Using this marker, Saurodactylus is paraphyletic, with S. mauritanicus and S. brosseti sister taxa to Teratoscincus przewalskii rather than Saurodactylus fasciatus . This is supported by a further nuclear marker, RAG1 , although for this gene region sampling is more limited. Based on this paraphyly, supported by two independent nuclear markers, we suggest it likely that Saurodactylus will need to be partitioned into two genera, pending further investigations.

A Combination of Divergence and Conservatism in the Niche Evolution of the Moorish Gecko, Tarentola mauritanica (Gekkota: Phyllodactylidae)

The quantification of realized niche overlap and the integration of species distribution models (SDMs) with calibrated phylogenies to study niche evolution are becoming not only powerful tools to understand speciation events, but can also be used as proxies regarding the delimitation of cryptic species. We applied these techniques in order to unravel how the fundamental niche evolved during cladogenesis within the Tarentola mauritanica species-complex. Our results suggest that diversification within this complex, during the Miocene and Pleistocene, is associated with both niche divergence and niche conservatism, with a pattern that varies depending on whether the variables involved are related to the mean or seasonality of temperature and humidity. Moreover, climatic variables related to humidity and temperature seasonality were involved in the niche shift and genetic diversification of the European/North African clade during the Pleistocene and in its maintenance in a fundamental niche distinct from that of the remaining members of the group. This study further highlights the need for a taxonomic revision of the T. mauritanica species-complex.

High Diversity of Hepatozoon spp. in Geckos of the Genus Tarentola

Abstract:   Hemogregarines are the most-commonly reported hemoparasites in reptiles. In this work we analyzed samples from 572 individuals of 6 species of the wall gecko genus Tarentola from European and African countries adjacent to the Mediterranean Sea as well as from the Macaronesian islands. Screening was done using hemogregarine-specific primers for the 18S rRNA gene. Positive amplifications were sequenced so that the diversity of the hemogregarines from these hosts could be assessed within a phylogenetic framework. The results from the phylogenetic analysis showed that within Tarentola, the detected parasites are comprised of at least 4 distinct main lineages of Hepatozoon spp. In clades A and B, the new sequences clustered closely together with the ones previously known from individuals of the genus Tarentola and other species of geckos but also with those from other vertebrate host groups including skinks, snakes, iguanids, and rodents. Clade C included a sample from Tarentola angustimentalis of the Canary Islands. This sequence is the first molecular characterization of these hemogregarines in this archipelago. Until now, this lineage had only been found in lacertids, skinks, and snakes, so this infection extends the host range for this clade. Lastly, in the newly detected clade D, the retrieved parasite sequences form a group currently identified as exclusive of geckos. Our results show that geckos of Tarentola spp. harbor a great diversity of hemogregarines but also that further sampling and other tools, including a multi-locus approach using faster-evolving genetic markers, and identification of definitive hosts are needed to better understand the biology, diversity, and distribution of these parasites.

Ecophysiology Tracks Phylogeny and Meets Ecological Models in an Iberian Gecko

Because fitness of ectotherms, including reptiles, is highly dependent on temperature and water availability, the study of ecophysiological traits, such as preferred temperature (T p) and water loss rates (WLRs), may provide mechanistic evidence on the restricting factors to the species ranges. The Moorish gecko, Tarentola mauritanica, is a species complex with a circum-Mediterranean distribution. In the Iberian Peninsula, two sister parapatric forms of the complex, known as the Iberian and the European clades, are found. Ecological models previously performed using presence records and bioclimatic variables suggest niche divergence between both lineages correlated with precipitation rather than with temperature. In this study, we test this correlative hypothesis using ecophysiological evidence. In the laboratory, we analyzed the T p and WLRs for 84 adult males from seven distinct populations ascribed to one of the two lineages present in Iberia. Specifically, we evaluated the existence of trait conservatism versus adaptation among populations, lineages, or both. In addition, we tested for a trade-off between water and thermal traits and assessed whether climate regime of sampling localities had any influence on the ecophysiological patterns found. We found that T p is quite conserved at both the population and lineage levels and independent from body size. In contrast, water loss experiments revealed some variation among populations, but the regression analysis failed to detect correlation between T p and WLR at any level. Overall, the European lineage displayed a trend for higher water loss and was more diverse among populations when compared with the Iberian lineage. The lack of correspondence between ecophysiological traits and local climatic conditions favors phylogenetic signal versus adaptation. This suggests divergent evolutionary responses to the environment, mainly acting on water ecology, in both lineages, which may account for the differences in their range expansion.

Lateralization in Escape Behaviour at Different Hierarchical Levels in a Gecko: Tarentola angustimentalis from Eastern Canary Islands

At the individual level, to be behaviourally lateralized avoids costly duplication of neural circuitry and decreases possible contradictory order from the two brain hemispheres. However, being prey behaviour lateralized at higher hierarchical levels could generate different negative implications, especially if predators are able to make predictions after multiple encounters. These conflicting pressures, namely between the advantages for individuals and the disadvantages for populations could be concealed if higher-level lateralization would arise from the combination of lateralized behaviours of individuals which are mutually dependent. Here, we investigated the lateralization patterns in the escape behaviour of the gecko Tarentola angustimentalis undergoing a predatory attack simulation in a “T” maze experiment. Results showed that gecko populations displayed different degrees of lateralization, with an overall dominance of right-biased individuals. This trend is similar to that observed in the Podarcis wall lizards, which share predators with Tarentola. In addition, different morphological parameters plausible to affect refuge selection were explored in order to link directional asymmetries at morphological level with lateralization during refuge selection.

Evolutionary History of the Morocco lizard-Fingered Geckos of the Saurodactylus brosseti Complex

Studies of biodiversity in the Maghreb have revealed high genetic diversity and divergent genetic lineages among many taxa including squamates. Geographic barriers such as the Atlas Mountains are one of the key factors promoting genetic differentiation and the high levels of endemism. The lizard-fingered gecko Saurodactylus brosseti is endemic to Morocco. Its range includes both sides of the Atlas Mountains, and although high diversity was previously identified within the species, much of the range was unsampled. To understand the evolutionary and biogeographical history of this species, we used mitochondrial and nuclear DNA sequence data from 64 populations sampled across the entire species range. We employed phylogenetic methods based on gene trees and species trees as well as a time calibrated Bayesian genealogy and coalescent species delimitation approaches. We uncovered four highly divergent and allopatric mitochondrial lineages that did not share haplotypes at variable nuclear loci, suggesting the four groups have been evolving independently since the Miocene, according to our molecular dating estimates. These results coupled with the geographic pattern of genetic diversity suggest a possible role of the Atlas Mountains for the divergence observed between the four lineages of S. brosseti, while each lineage probably later underwent several episodes of fragmentation followed by (re-) expansion during Pleistocene climatic oscillations. Bayesian species delimitation analysis indicates that the four lineages may well be distinct species but we suggest that detailed morphological analyses are needed prior to taxonomic changes. The four lineages represent ancient independent evolutionary units, and deserve conservation management as distinct entities.

Why are Red List species not on the EDGE? A response to Winter et al.

Winter et al. [1], Rosauer and Mooers [2] and Winter et al. [3] discuss the importance of evolutionary diversity, and highlight its limited role in practical nature conservation. We suggest that the International Union for Conservation of Nature (IUCN) Red List, which is by far the largest and most comprehensive assessment of conservation status, actually acerbates the problem.

Evolutionary patterns of the mitochondrial genome in the Moorish gecko, Tarentola mauritanica

A previous study on the evolutionary patterns of Tarentola mauritanica demonstrated that low levels of mitochondrial diversity observed in the European populations relative to nuclear markers were consistent with a selective sweep hypothesis. In order to unravel the mitochondrial evolutionary history in this European population and two other lineages of T. mauritanica (Iberian and North African clades), variation within 22 nearly complete mitogenomes was analyzed. Surprisingly, each clade seems to have a distinct evolutionary history; with both the European and Iberian clades presenting a decrease of polymorphism, which in the former is consistent with departure from neutrality of the mtDNA (positive or background selection), but in the latter seems to be the result of a bottleneck after a population expansion. The pattern exhibited by the North African clade seems to be a consequence of adaptation to certain mtDNA variants by positive selection.