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The taxonomy of the fringe-toed lizards of the Acanthodactylus scutellatus group has long been unstable and no consensus exists on the systematic status of its various forms. A multivariate analysis of morphological characters, performed on over 1000 specimens from most of the African range of this group, allowed us to clarify the specific allocation of most of the Saharan populations included in this species group. Based on comparisons of morphology between allopatric and sympatric populations of this complex, we propose the recognition of six biological species. Our results confirm the specific status of Acanthodactylus aureus , A. dumerili , A. scutellatus, A. longipes and the recently described A. taghitensis . In addition, we re-validate A. senegalensis (occurring from Mauritania and Mali south to Senegal), which has been treated as a synonym of A. dumerili by previous authors. Acanthodactylus longipes is reported for the first time from coastal Mauritania, and A. taghitensis (previously known only from a very small region in Algeria) is reported from continental Mauritania. The systematic section of this paper includes a full list of examined material, diagnosis and known distribution of each species, in addition to some information on geographical variation and ecology. A key for specific identification is provided as an appendix.

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Se aportan los resultados herpetológicos de una expedición científica realizada en abril-mayo de 2012 al sur de Niger, una remota zona que incluye la Reserva Natural de Termit & Tin Toumma. Se observaron 27 especies de reptiles y tres de anfibios. Debido al elevado des- conocimiento herpetológico de la región, muchas de las nuevas citas aumentan o cubren gran- des vacios en la distribución de las especies halladas.

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Abstract. A recent field trip to Niger allowed herpetological exploration of the Termit Massif (southeastern Tenere Desert), an area rarely visited by herpetologists. A total of 13 species were collected or observed, some typical of Saharan habitats and others related to more mesic Sahelian habitats. The later species are mostly restricted to temporary humid river beds locally called ‘kori’. Our field data were completed by observations made during several years in the frame of the ‘Project Sahelo- Saharan Antelopes’ (Sahara Conservation Fund) in the same area and neighbouring Tin Toumma and another mammal oriented field trip, confirming species occurrence and providing data for four additional species, thus totalling 17 species for the area. Note however that more species should be present and potential species are discussed. We here report the occurrence of Acanthodactylus senegalensis from the country by vouchers, thus confirming its considerable eastern extension only recently reported. Some ecomorphological external characters allowing easy distinction between Acanthodactylus longipes and A. senegalensis are provided. The most surprising feature of Termit Massif’s herpetofauna is the lack of numerous genera and species occurring Northwest of Termit at Aïr Massif and sometimes even in the southern part of the country (e.g. Uromastyx and Ptyodactylus). Such differences between Aïr and Termit herpetofaunas are explained by more arid conditions at the later place, the Aïr Mountains being an efficient barrier to clouds, thus offering more mesic habitats to its herpetofauna.

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Aim To map and assess the richness patterns of reptiles (and included groups: amphisbaenians, crocodiles, lizards, snakes and turtles) in Africa, quantify the overlap in species richness of reptiles (and included groups) with the other terrestrial vertebrate classes, investigate the environmental correlates underlying these patterns, and evaluate the role of range size on richness patterns. Location Africa. Methods We assembled a data set of distributions of all African reptile species. We tested the spatial congruence of reptile richness with that of amphibians, birds and mammals. We further tested the relative importance of temperature, precipitation, elevation range and net primary productivity for species richness over two spatial scales (ecoregions and 1° grids). We arranged reptile and vertebrate groups into range-size quartiles in order to evaluate the role of range size in producing richness patterns. Results Reptile, amphibian, bird and mammal richness are largely congruent (r = 0.79–0.86) and respond similarly to environmental variables (mainly productivity and precipitation). Ecoregion size accounts for more variation in the richness of reptiles than in that of other groups. Lizard distributions are distinct with several areas of high species richness where other vertebrate groups (including snakes) are species-poor, especially in arid ecoregions. Habitat heterogeneity is the best predictor of narrow-ranging species, but remains relatively important in explaining lizard richness even for species with large range sizes. Main conclusions Reptile richness varies with similar environmental variables as the other vertebrates in Africa, reflecting the disproportionate influence of snakes on reptile richness, a result of their large ranges. Richness gradients of narrow-ranged vertebrates differ from those of widespread taxa, which may demonstrate different centres of endemism for reptile subclades in Africa. Lizard richness varies mostly with habitat heterogeneity independent of range size, which suggests that the difference in response of lizards is due to their ecological characteristics. These results, over two spatial scales and multiple range-size quartiles, allow us to reliably interpret the influence of environmental variables on patterns of reptile richness and congruency.

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Aim Body size is instrumental in influencing animal physiology, morphology, ecology and evolution, as well as extinction risk. I examine several hypotheses regarding the influence of body size on lizard evolution and extinction risk, assessing whether body size influences, or is influenced by, species richness, herbivory, island dwelling and extinction risk. Location World-wide. Methods I used literature data and measurements of museum and live specimens to estimate lizard body size distributions. Results I obtained body size data for 99% of the world`s lizard species. The body size–frequency distribution is highly modal and right skewed and similar distributions characterize most lizard families and lizard assemblages across biogeographical realms. There is a strong negative correlation between mean body size within families and species richness. Herbivorous lizards are larger than omnivorous and carnivorous ones, and aquatic lizards are larger than non-aquatic species. Diurnal activity is associated with small body size. Insular lizards tend towards both extremes of the size spectrum. Extinction risk increases with body size of species for which risk has been assessed. Main conclusions Small size seems to promote fast diversification of disparate body plans. The absence of mammalian predators allows insular lizards to attain larger body sizes by means of release from predation and allows them to evolve into the top predator niche. Island living also promotes a high frequency of herbivory, which is also associated with large size. Aquatic and nocturnal lizards probably evolve large size because of thermal constraints. The association between large size and high extinction risk, however, probably reflects a bias in the species in which risk has been studied.

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This is the first comprehensive review of the reptiles of Mauritania. It includes distributional information and comments. Mauritania harbors 86 species of reptiles belonging to 21 families. Among these families, Colubridae and Lacertidae are the most diverse, with 14 and 13 species respectively. Other families, such as Agamidae, Gekkonidae, Scincidae or Viperidae are also well represented. Among the 80 continental species, 47.5% are Saharan, 33.8% Afrotropical, 16.2% Sahelian and 2.5% Mediterranean. The marine turtles form another important group, with six species. Eight species are excluded from the country list because of old identification errors, there is not enough evidence of their presence or due to changes in political borders. Among the species expected to occur in Mauritania, at least nine may occur in Saharan environments, 13 in the Sahel savannah and two may have been introduced.

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This study provides the first atlas of the distribution of reptiles in the Parc National du Banc d’Arguin, Mauritania. The area is a UNESCO World Heritage Site and a Nature Reserve. Unpublished fieldwork observations collected between 2008 and 2011 were combined with published records and museum data in a Geographical Information System to produce maps with the distribution of individual species and species richness. The taxonomic list of repti- les includes 21 species grouped in eight families. Three species (Stenodactylus mauritanicus, Mesalina pasteuri and Psammophis sibilans) were detected for the first time in the area. Reptiles form distinct groups according to their dis- tribution patterns and preliminary habitat selection trends: 1) species selecting bare areas present throughout the park; 2) species selecting rocky habitats present mostly in the northern areas; and 3) species selecting sandy habitats present mostly in the southern areas. A total of eight areas were identified as of high species richness (N > 8 species), usually presenting species typical of rocky or dune habitats and also species present in open bare areas.

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Acanthodactylus lizards are among the most diverse and widespread diurnal reptiles in the arid regions spanning from North Africa across to western India. Acanthodactylus constitutes the most species-rich genus in the family Lacertidae, with over 40 recognized species inhabiting a wide variety of dry habitats. The genus has seldom undergone taxonomic revisions, and although there are a number of described species and species-groups, their boundaries as well as their interspecific relationships are largely unresolved. We constructed a multilocus phylogeny, combining data from two mitochondrial (12S, cytb) and three nuclear (MC1R, ACM4, c-mos) markers for 302 individuals belonging to 36 known species, providing the first large-scale time-calibrated molecular phylogeny of the genus. We evaluated phylogenetic relationships between and within species-groups, and assessed Acanthodactylus biogeography across its known range. Acanthodactylus cladogenesis is estimated to have originated in Africa due to vicariance and dispersal events from the Oligocene onwards. Radiation started with the separation into three clades: the Western and scutellatus clades largely distributed in North Africa, and the Eastern clade occurring mostly from Arabia to south-west Asia. Most Acanthodactylus species diverged during the Miocene, possibly as a result of regional geological instability and climatic changes. We support most of the current taxonomic classifications and phylogenetic relationships, and provide genetic validity for most species. We reveal a new distinct blanfordii species-group, suggest new phylogenetic positions (A. hardyi, A. masirae), and synonymize several species and subspecies (A. lineomaculatus, A. boskianus khattensis and A. b. nigeriensis) with their phylogenetically closely-related species. We recommend a thorough systematic revision of taxa exhibiting high levels of intraspecific variability as well as clear evidence of phylogenetic complexity such as A. guineensis, A. grandis, A. dumerilii, and A. senegalensis and the pardalis and erythrurus species-groups.

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Aim: Hyper-arid sandy and rocky fields rank among the least biologically diverse habitats of the desert biome, yet knowledge of local biodiversity patterns is also ex tremely poor. In the Sahara Desert, palaeoclimate oscillations affected the extent of hyper-arid habitats, but it is unclear how these dynamics determined the evolution and distribution of local specialists. Herein, we assessed cryptic diversity, diversification patterns and spatial connectivity within a Sahara-widespread group of dryland adapted lizards. Location: Sahara-Sahel ecoregions. Taxon: Acanthodactylus scutellatus species group. Methods: Inter- and intraspecific phylogenetic structure, divergence times, spatial genetic patterns and cryptic diversity were assessed using nuclear and mitochondrial loci. The effects of topography and land cover on phylogeographic structure and diversity were tested with generalized linear models. Interspecific hybridization was evaluated using 11 microsatellites across the group`s major sympatry zone, predicted based on ecological niche models. Results: Species of Acanthodactylus scutellatus group exhibit Late Miocene origins, followed by extensive intraspecific divergence throughout the Pliocene. The northern Sahara worked as a major diversification hotspot, harbouring a patchwork of small ranged, divergent lineages. These lineages are parapatric or sympatric and present concordant nuclear and mitochondrial differentiation, suggesting species status. Genetic connectivity increases in southern latitudes, with wide-ranging lineages spanning from the Red Sea to the Atlantic coast. Within these potential corridors, mountain outskirts and sand fields in the Sahara interior seemingly acted as origins for recent population expansions. Genetic diversity and connectivity are favoured by terrain roughness and soft-sand cover respectively. Three species inhabit the Atlantic Sahara sympatry zone without evidence of gene flow. Main conclusions: Overlooked species-level diversity within a major specialist group of Sahara drylands exposes the recurrent knowledge shortfalls present in hyper-arid desert environments. Humidity and sandy habitat shifts triggered potential successions of population isolation and re-connectivity, which favoured cladogenesis in northern desert regions and population expansions across southern east–west corridors.