Species on the rocks: Systematics and biogeography of the rock-dwelling Ptyodactylus geckos (Squamata: Phyllodactylidae) in North Africa and Arabia

Hidden in the sand: Phylogenomics unravel an unexpected evolutionary history for the desert-adapted vipers of the genus Cerastes

The desert vipers of the genus Cerastes are a small clade of medically important venomous snakes within the family Viperidae. According to published morphological and molecular studies, the group is comprised by four species: two morphologically similar and phylogenetically sister taxa, the African horned viper (Cerastes cerastes) and the Arabian horned viper (Cerastes gasperettii); a more distantly related species, the Saharan sand viper (Cerastes vipera), and the enigmatic Böhme's sand viper (Cerastes boehmei), only known from a single specimen in captivity allegedly captured in Central Tunisia. In this study, we sequenced one mitochondrial marker (COI) as well as genome-wide data (ddRAD sequencing) from 28 and 41 samples, respectively, covering the entire distribution range of the genus to explore the population genomics, phylogenomic relationships and introgression patterns within the genus Cerastes. Additionally, and to provide insights into the mode of diversification of the group, we carried out niche overlap analyses considering climatic and habitat variables. Both nuclear phylogenomic reconstructions and population structure analyses have unveiled an unexpected evolutionary history for the genus Cerastes, which sharply contradicts the morphological similarities and previously published mitochondrial approaches. Cerastes cerastes and C. vipera are recovered as sister taxa whilst C. gasperettii is a sister taxon to the clade formed by these two species. We found a relatively high niche overlap (OI > 0.7) in both climatic and habitat variables between C. cerastes and C. vipera, contradicting a potential scenario of sympatric speciation. These results are in line with the introgression found between the northwestern African populations of C. cerastes and C. vipera. Finally, our genomic data confirms the existence of a lineage of C. cerastes in Arabia. All these results highlight the importance of genome-wide data over few genetic markers to study the evolutionary history of species.

The evolutionary journey of freshwater crabs of the genus Potamon (Decapoda: Brachyura: Potamidae)

AIM

Freshwater ecosystems host a rich biodiversity, including freshwater crabs. The family Potamidae is a diverse group of freshwater crabs with a Palearctic and Oriental distribution. Specifically, the genus Potamon is found in the Middle East, Southern Europe, and Northern Africa. Potamon species are considered true freshwater crabs due to their total independence from the marine environment, which makes them idea organisms to study historical freshwater connectivity dynamics. In this study we aim to elucidate the phylogenetic relationships of the genus Potamon and discuss the historical freshwater connectivity in the Mediterranean region.

METHODS

Here we use up to eleven genetic markers to reconstruct a robust phylogenetic tree of the group and use Bayesian methods to time-calibrate the tree. We further use historical biogeography methods implemented in a Bayesian framework to assess the ancestral distribution ranges of the group.

RESULTS

In this study we generate the most complete dataset for the group, covering practically the whole distribution range of the genus. We obtained a robust phylogenetic hypothesis and evaluated the times of divergence of the group. The result of the historical biogeography shows the evolution of historical distribution ranges of species of Potamon.

MAIN CONCLUSIONS

The Mediterranean Sea is placed in a key intersection for the exchange of fauna and flora. Here we present evidence for the potential of freshwater fauna exchange, through the Mediterranean Sea after a period of desiccation and the loss of contact with the ocean. The origin of Potamon genus is found to be in Western Asia, probably Eastern Iran.

DNA barcode reference library for the West Sahara-Sahel reptiles

DNA barcode reference libraries are now continuously produced for the tree of life, which are essential pillars for the study of biological diversity. Yet, our knowledge about global diversity is largely limited in undersampled regions such as the largest warm desert, the Sahara-Sahel. This dataset provides a DNA barcode reference library for the reptiles of the Western Sahara-Sahel (WSS) and neighbouring countries across this region. It includes 760 barcodes from 133 reptile taxa, distributed in 23 families, and covering the intraspecific diversity of some species. A total of 84 species were collected in the WSS (83% of the total reptile species richness) over 18 overland field expeditions conducted since 2003. DNA barcodes resulted in a high success rate (95%) of species identification and barcoding gap analysis highlighted the effectiveness of the COI fragment as a barcode marker for the WSS reptiles. This dataset represents a comprehensive and reliable DNA reference library for the WSS, filling an important biodiversity gap across a remote and hard-to-sample region.

Measurement(s)	reptile diversity
Technology Type(s)	DNA barcoding
Factor Type(s)	DNA barcode sequencing
Sample Characteristic - Organism	reptiles
Sample Characteristic - Environment	terrestrial
Sample Characteristic - Location	Western Sahara-Sahel

Conserved ecophysiology despite disparate microclimatic conditions in a gecko

Microscale differences in the habitats organisms occupy can influence selection regimes and promote intraspecific variation of traits. Temperature-dependent traits can be locally adapted to climatic conditions or be highly conserved and insensitive to directional selection under all but the most extreme regimes, and thus be similar across populations. The opposing slopes of Nahal Oren canyon in the Carmel Mountains, Israel, are strikingly different: the south-facing slope receives intensive solar radiation, is hot and supports mostly annual vegetation, whereas the north-facing slope is ~10°C cooler, more humid, and supports Mediterranean woodland. We examined whether these differences manifest in the thermal physiology of a common gecko species Ptyodactylus guttatus in controlled laboratory conditions. We predicted that geckos from the hotter south-facing slope would prefer higher temperatures, have faster gut passage times, lower metabolic and evaporative water loss rates, and start diel activity earlier compared with north-facing slope conspecifics. Contrary to these predictions, there were no differences between any of the ecophysiological traits in geckos from the opposing slopes. Nevertheless, our data showed that individuals from the north-facing slope were generally more active in earlier hours of the afternoon compared with south-facing individuals. We suggest that P. guttatus individuals disperse between the slopes and either gene-flow or behavioral plasticity deter local adaptation, resulting in similar physiological traits. Perhaps a stronger contrast in climatic conditions and a stronger barrier are needed to result in interpopulation divergence in temperature-dependent traits.

Ecological specialization, rather than the island effect, explains morphological diversification in an ancient radiation of geckos

Island colonists are often assumed to experience higher levels of phenotypic diversification than continental taxa. However, empirical evidence has uncovered exceptions to this 'island effect'. Here, we tested this pattern using the geckos of the genus Pristurus from continental Arabia and Africa and the Socotra Archipelago. Using a recently published phylogeny and an extensive morphological dataset, we explore the differences in phenotypic evolution between Socotran and continental taxa. Moreover, we reconstructed ancestral habitat occupancy to examine if ecological specialization is correlated with morphological change, comparing phenotypic disparity and trait evolution between habitats. We found a heterogeneous outcome of island colonization. Namely, only one of the three colonization events resulted in a body size increase. However, in general, Socotran species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialization explains better the body size and shape evolution in Pristurus. Particularly, the colonization of ground habitats appears as the main driver of morphological change, producing the highest disparity and evolutionary rates. Additionally, arboreal species show very similar body size and head proportions. These results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in continent-island systems.

Habitat selection by the Spiny-tailed lizard (Uromastyx aegyptia): A view from spatial analysis

Many factors affect the habitat selection for animal species, which in turn may greatly affect their distribution in different ecosystems. Understanding the processes that affect habitat selection is also critical for guiding and managing conservation initiatives. Our study aimed to assess the habitat selection by free-ranging Spiny-tailed lizard (Uromastyx aegyptia) by analyzing a geospatial data connecting its burrow parameters to different habitat characteristics within selected sites in Hail region, Saudi Arabia. We examined evidence and patterns of significant spatial clustering for (366) active burrows by linking their parameters (burrow entrance size, burrow entrance width and burrow entrance height), their reference geographical locations and, two habitat characteristics defined by soil type and vegetation cover. The objective of the analysis was to increase the understanding on the burrows aggregation process in the space and, to describe its possible relation to other spatial habitat configurations. Analysis of distances based on the Nearest Neighbor Index (NNI) and hotspots detection in Nearest neighbor hierarchical clustering (Nnh) suggested twelve (12) spatial clusters located within the study area. In addition, a spatial ordinary least square (OLS) and Poisson regression models revealed significant effects of soil type and vegetation cover on burrow parameters (OLS, p < 0.05; Poisson, p < 0.001), which indicate a strong association between burrows parameters and habitats characteristics. Findings from the study also suggest that other factors such as elevations, highways, and human settlement concentration spots could possibly play a major role in defining burrow spatial aggregation and furthermore have a significant impact on habitat selection.

Reconstructing Squamate Biogeography in Afro-Arabia Reveals the Influence of a Complex and Dynamic Geologic Past

The geographic distribution of biodiversity is central to understanding evolutionary biology. Paleogeographic and paleoclimatic histories often help to explain how biogeographic patterns unfold through time. However, such patterns are also influenced by a variety of other factors, such as lineage diversification, that may affect the probability of certain types of biogeographic events. The complex and well-known geologic and climatic history of Afro-Arabia, together with the extensive research on reptile systematics in the region, makes Afro-Arabian squamate communities an ideal system to investigate biogeographic patterns and their drivers. Here we reconstruct the phylogenetic relationships and the ancestral geographic distributions of several Afro-Arabian reptile clades (totaling 430 species) to estimate the number of dispersal, vicariance and range contraction events. We then compare the observed biogeographic history to a distribution of simulated biogeographic events based on the empirical phylogeny and the best-fit model. This allows us to identify periods in the past where the observed biogeographic history was likely shaped by forces beyond the ones included in the model. We find an increase in vicariance following the Oligocene, most likely caused by the fragmentation of the Afro-Arabian plate. In contrast, we did not find differences between observed and expected dispersal and range contraction levels. This is consistent with diversification enhanced by environmental processes and with the establishment of a dispersal corridor connecting Africa, Arabia and Eurasia since the middle Miocene. Finally, here we show that our novel approach is useful to pinpoint events in the evolutionary history of lineages that might reflect external forces not predicted by the underlying biogeographic model.

Systematics, biogeography and evolution of the Saharo-Arabian naked-toed geckos genus Tropiocolotes

Plate tectonics constitute one of the main mechanisms of biological diversification on Earth, often being associated with cladogenetic events at different phylogenetic levels, as well as with exchange of faunas and floras across previously isolated biogeographic regions. North Africa and Arabia share a complex geological history that dates back to the break-up of the Arabian plate from the African plate ~30-25 Mya, followed by various geological events, such as the formation of the Red Sea or the connection between the African, Arabian and Eurasian plates. Species with Saharo-Arabian distributions have shown a close association between their evolutionary history and these geological events. In this study, we investigate the systematics, biogeography and evolution of the genus Tropiocolotes, a group of small ground-dwelling geckos, comprised by 12 species distributed from the Atlantic coast of North Africa to southwestern Iran. Species delimitation analyses uncovered the existence of high levels of undescribed diversity, with forms here considered at the species level including Tropiocolotes tripolitanus (Mauritania and southern Morocco), T. nattereri (southern Israel) and T. scorteccii (Yemen and Oman). Phylogenetic and biogeographic analyses recovered two main clades, an exclusively African clade and a Saharo-Arabian clade, that split ~25 Mya following the vicariant event mediated by the separation of the Arabian and African plates. The complex geological activity around the Red Sea is associated with the diversification within the Saharo-Arabian clade, including the colonization of North Africa from a second Tropiocolotes group. Results also provide new insights into the geographic distribution of Tropiocolotes nubicus, previously considered as exclusively associated to the Nile River valley, extending its known distribution further west, up to the Central Mountains of the Sahara. Accordingly, the Nile River seems to act as a major biogeographic barrier, separating Tropiocolotes nubicus and T. steudneri in their western and eastern margins, respectively.

Classifying biogeographic realms of the endemic fauna in the Afro-Arabian region

AIM

Understanding diversity patterns and identifying the environmental factors that shape these patterns are essential for ecology and conservation. The Afro-Arabian region comprises one of the most important biogeographic areas connecting continents. Yet, little emphasis has been put on understanding its endemic fauna in relation to its biogeographic realms. Our objective is to fill the gaps in knowledge on diversity patterns and biogeography that are essential for prioritizing the overdue conservation efforts.

LOCATION

The study area covers mostly the hot desert climate region in North Africa and Arabia, and includes the Mediterranean, Sahel, and Ethiopian highlands (hereafter "Afro-Arabian region").

METHODS

We used distribution maps developed by IUCN and BirdLife for species endemic to the Afro-Arabian region belonging to the four tetrapod classes, amphibians, reptiles, birds, and mammals, to identify the endemic richness hotspots. We then used multivariate analyses to delineate biogeographic regions and evaluate their relationship with the environmental factors.

RESULTS

Our study reveals a complex map of the richness hotspots for the endemic tetrapod classes. The main hotspots of endemism were concentrated at the margins of the study area, along the Mediterranean coast, Ethiopian highlands, and along the Red Sea Mountains. We propose classifying the Afro-Arabian region into three discrete biogeographic realms for endemic amphibians, four for reptiles and birds, and five discrete biogeographic realms for endemic mammals. The identified realms are defined by their environmental conditions and the historical geological processes.

MAIN CONCLUSIONS

Richness hotspots of endemic tetrapod classes were heterogeneously distributed in the Afro-Arabian region. Our results support the hypothesis that species diversity patterns and endemism have been shaped by the environmental conditions and the paleogeographic processes. Each of the identified bioregions is associated with a characteristic set of tetrapod species. Our results are a benchmark for assessing the effectiveness of the protected areas and for implementing conservation plans for biodiversity.

Using multilocus approach to uncover cryptic diversity within Pseudotrapelus lizards from Saudi Arabia

The agamid Pseudotrapelus lizards inhabit the mountainous areas of the Arabian Peninsula and eastern North Africa. Currently six Pseudotrapelus species are recognised, though diagnostic morphological characters are still lacking, creating great difficulty in describing new species. Recently, two specimens of Pseudotrapelus were collected from the vicinity of Riyadh in central Saudi Arabia, an area that was not sampled in previous phylogenetic studies. In here we used both mitochondrial and nuclear data to investigate the phylogenetic position of the new samples, and assess their phylogenetic relationships with the other recognised species of Pseudotrapelus from across the distribution range of the genus. We used a multilocus approach of haplotype networks, concatenated datasets and species trees, performed mitochondrial and nuclear species delimitation analyses, and estimated divergence times. In general, our results support previous molecular studies and uncover the presence of cryptic diversity within Pseudotrapelus. The phylogenetic structure of the genus is of two major clades and within them seven distinct, delimited phylogenetic groups belonging to the six recognised species and the seventh to the individuals from Riyadh. The Riyadh specimens were distinct in all analyses performed. We suggest that the new specimens from the Riyadh area are a distinct lineage, forming a clade with their phylogenetic relatives, P. sinaitus and P. chlodnickii. The clade formed by these three species diverged during the Late Miocene around 6.4 Ma, with cladogenesis possibly facilitated by vicariance and isolation caused due to climatic fluctuations and the progression of sandy areas. Our results suggest further morphological research is necessary to revise the taxonomic status of this lineage and of the entire genus.

An integrative assessment of the diversity, phylogeny, distribution, and conservation of the terrestrial reptiles (Sauropsida, Squamata) of the United Arab Emirates

In the present study we use an unprecedented database of 5,535 distributional records to infer the diversity, ecological preferences and spatial distribution of the 60 species of terrestrial reptiles of the United Arab Emirates (UAE), and use the 57 native species to test the effectiveness of the protected areas’ network in conserving this unique vertebrate fauna. We infer a time-calibrated phylogeny with 146 species of squamates and 15 genes including all UAE terrestrial reptile species to determine the phylogenetic diversity (PD) and evolutionary distinctiveness (ED) of the native species and to compare it with the distribution of the hotspots of native species richness. The results of this study indicate that the sampling effort is remarkable, covering 75% of the country’s territory representing nearly the entire climatic space of the UAE defined by the mean annual temperature and the total annual precipitation, as well as the multivariate climatic space defined by a principal component analysis (PCA). Species richness is highest in the northeast of the country, in a transitional area from sandy desert to the mountainous terrain of the Hajar Mountains. The highest PD of a single square cell of 10 arc-minutes grid is of 2,430 million years (my) of accumulated evolutionary history and the strong correlation between PD and species richness suggests that the raw number of species is a good surrogate to quantify the evolutionary history (i.e., PD). The species with the highest values of ED are those in families represented by only one species in the UAE. Finally, the assessment of the UAE protected areas shows that, despite their relevance in protecting the terrestrial reptiles, they do not offer adequate protection for some threatened species. Therefore, a reassessment of some of the protected areas or the creation of species specific conservation action plans are recommended in order to ensure the preservation of the unique diversity of UAE terrestrial reptiles.

Dispersal beyond geographic barriers: a contribution to the phylogeny and demographic history of Pristurus rupestris Blanford, 1874 (Squamata: Sphaerodactylidae) from southern Iran

Pristurus rupestris is a member of Semaphore geckos with a wide distribution range. Recently, 14 candidate species of P. rupestris rupestris have been identified in the Hajar Mountains (Arabia), yet the knowledge on the Iranian counterparts is limited. The present study elucidates the phylogenetic position of the Iranian P. rupestris and investigates the hypothesis on its historical colonization from Oman to Iran and the associated islands. Therefore, 20 Iranian specimens along with 115 individuals from Oman were examined using two mitochondrial genes including the Cytochrome b and the 12S ribosomal RNA. The molecular phylogenetic analyses revealed that the individuals collected from Iran are well nested within the candidate Species 3 of P. r. rupestris, demonstrating a single population with high gene flow. Additionally, the molecular analyses showed that the genetic diversity within the Iranian Blanford's Semaphore geckos is low and that the candidate Species 3 experienced a recent expansion approximately 17 thousand years ago (Kya). The historical demographic analyses (BSP) showed a mild increase in the effective population size between 15-20 Kya. These time estimations coincide with the Last Glacial Maximum, when the Persian Gulf was almost dry, reinforcing the hypothesis that the species might have colonized southern Iran from Oman through the Persian Gulf. In addition, we propose P. r. iranicus to be synonymized with P. r. rupestris.

Ancient diversification, biogeography, and the role of climatic niche evolution in the Old World cat snakes (Colubridae, Telescopus)

The process of species diversification is often associated with niche shifts in the newly arising lineages so that interspecific competition is minimized. However, an opposing force known as niche conservatism causes that related species tend to resemble each other in their niche requirements. Due to the inherent multidimensionality of niche space, some niche components may be subject to divergent evolution while others remain conserved in the process of speciation. One such possible component is the species' climatic niche. Here, we test the role of climatic niche evolution on the diversification of the Old World cat snakes of the genus Telescopus. These slender, nocturnal snakes are distributed in arid and semiarid areas throughout Africa, southwest Asia and adjoining parts of Europe. Because phylogenetic relationships among the Telescopus species are virtually unknown, we generated sequence data for eight genetic markers from ten of the 14 described species and reconstructed a time-calibrated phylogeny of the genus. Phylogenetic analysesindicate that the genus is of considerably old origin that dates back to the Eocene/Oligocene boundary. Biogeographical analyses place the ancestor of the genus in Africa, where it diversified into the species observed today and from where it colonized Arabia and the Levant twice independently. The colonization of Arabia occurred in the Miocene, that of the Levant either in the Late Oligocene or Early Miocene. We then identified temperature and precipitation niche space and breadth of the species included in the phylogeny and examined whether there is phylogenetic signal in these climatic niche characteristics. Despite the vast range of the genus and its complex biogeographic history, most Telescopus species have similar environmental requirements with preference for arid to semiarid conditions. One may thus expect that the genus' climatic niche will be conserved. However, our results suggest that most of the climatic niche axes examined show no phylogenetic signal, being indicative of no evolutionary constraints on the climatic niche position and niche breadth in Telescopus. The only two variables with positive phylogenetic signal (temperature niche position and precipitation niche breadth) evolved under the Brownian motion model, also indicating no directional selection on these traits. As a result, climatic niche evolution does not seem to be the major driver for the diversification in Telescopus.

Comparative phylogeography of amphibians and reptiles in Algeria suggests common causes for the east-west phylogeographic breaks in the Maghreb

A series of phylogeographic studies in the Maghreb identified a repeated pattern of deep genetic divergence between an eastern (Tunisia) and western (Morocco) lineage for several taxa but lack of sampling in Algeria made it difficult to know if the range limits between the eastern and western lineages were shared among taxa or not. To address this question, we designed a comparative phylogeographic study using 8 reptile and 3 amphibian species with wide distribution in the Maghreb as models. We selected species where previous studies had identified an East-West phylogeographic divide and collected sampled in Algeria to 1) examine whether the simple East-West divergence pattern still holds after filling the sampling gap in Algeria or if more complex diversity patterns emerge; 2) if the E-W pattern still holds, test whether the limits between the E and W clades are shared between species, suggesting that common historical process caused the E-W divergences; 3) if E-W limits are shared between species, use information on the age of the divergence to identify possible geological or climatic events that could have triggered these E-W differentiations. We found that the E-W pattern was generally maintained after additional sampling in Algeria and identified two common disjunction areas, one around the Algeria-Morocco border, the other one in Kabylia (central Algeria), suggesting that common historical mechanisms caused the E-W divergences in the Maghreb. Our estimates for the times to most common recent ancestors to the E and W clades span a wide range between the Messinian salinity crisis and the Plio-Pleistocene limit (except for one older split), suggesting different origins for the initial divergences and subsequent preservation of the E and W lineages in common climatic refugia in the west and the east of the Maghreb.

Diversity, distribution and conservation of the terrestrial reptiles of Oman (Sauropsida, Squamata)

In the present work, we use an exceptional database including 5,359 records of 101 species of Oman’s terrestrial reptiles together with spatial tools to infer the spatial patterns of species richness and endemicity, to infer the habitat preference of each species and to better define conservation priorities, with especial focus on the effectiveness of the protected areas in preserving this unique arid fauna. Our results indicate that the sampling effort is not only remarkable from a taxonomic point of view, with multiple observations for most species, but also for the spatial coverage achieved. The observations are distributed almost continuously across the two-dimensional climatic space of Oman defined by the mean annual temperature and the total annual precipitation and across the Principal Component Analysis (PCA) of the multivariate climatic space and are well represented within 17 out of the 20 climatic clusters grouping 10% of the explained climatic variance defined by PC1 and PC2. Species richness is highest in the Hajar and Dhofar Mountains, two of the most biodiverse areas of the Arabian Peninsula, and endemic species richness is greatest in the Jebel Akhdar, the highest part of the Hajar Mountains. Oman’s 22 protected areas cover only 3.91% of the country, including within their limits 63.37% of terrestrial reptiles and 50% of all endemics. Our analyses show that large areas of the climatic space of Oman lie outside protected areas and that seven of the 20 climatic clusters are not protected at all. The results of the gap analysis indicate that most of the species are below the conservation target of 17% or even the less restrictive 12% of their total area within a protected area in order to be considered adequately protected. Therefore, an evaluation of the coverage of the current network of protected areas and the identification of priority protected areas for reptiles using reserve design algorithms are urgently needed. Our study also shows that more than half of the species are still pending of a definitive evaluation by the International Union for Conservation of Nature (IUCN).

Cryptic diversity in Ptyodactylus (Reptilia: Gekkonidae) from the northern Hajar Mountains of Oman and the United Arab Emirates uncovered by an integrative taxonomic approach

The Hajar Mountains of south-eastern Arabia form an isolated massif surrounded by the sea to the east and by a large desert to the west. As a result of their old geological origin, geographical isolation, complex topography and local climate, these mountains provide an important refuge for endemic and relict species of plants and animals. With 19 species restricted to the Hajar Mountains, reptiles are the vertebrate group with the highest level of endemicity, becoming an excellent model for understanding the patterns and processes that generate and shape diversity in this arid mountain range. The geckos of the Ptyodactylus hasselquistii species complex are the largest geckos in Arabia and are found widely distributed across the Arabian Mountains, constituting a very important component of the reptile mountain fauna. Preliminary analyses suggested that their diversity in the Hajar Mountains may be higher than expected and that their systematics should be revised. In order to tackle these questions, we inferred a nearly complete calibrated phylogeny of the genus Ptyodactylus to identify the origin of the Hajar Mountains lineages using information from two mitochondrial and four nuclear genes. Genetic variability within the Hajar Mountains was further investigated using 68 specimens of Ptyodactylus from 46 localities distributed across the entire mountain range and sequenced for the same genes as above. The molecular phylogenies and morphological analyses as well as niche comparisons indicate the presence of two very old sister cryptic species living in allopatry: one restricted to the extreme northern Hajar Mountains and described as a new species herein; the other distributed across the rest of the Hajar Mountains that can be confidently assigned to the species P. orlovi. Similar to recent findings in the geckos of the genus Asaccus, the results of the present study uncover more hidden diversity in the northern Hajar Mountains and stress once again the importance of this unique mountain range as a hot spot of biodiversity and a priority focal point for reptile conservation in Arabia.

An integrative systematic revision and biogeography of Rhynchocalamus snakes (Reptilia, Colubridae) with a description of a new species from Israel

BACKGROUND

The colubrid snakes of the genus Rhynchocalamus are seldom studied and knowledge of their ecology and life history is scarce. Three species of Rhynchocalamus are currently recognized, R. satunini (from Turkey eastwards to Iran), R. arabicus (Yemen and Oman), and R. melanocephalus (from the Sinai Peninsula northwards to Turkey). All are slender, secretive, mainly nocturnal and rare fossorial snakes. This comprehensive study is the first to sample all known Rhynchocalamus species in order to review the intra-generic phylogenetic relationships and historical biogeography of the genus.

METHODS

We revised the systematics of Rhynchocalamus using an integrative approach and evaluated its phylogeography. The phylogenetic position within the Colubridae and the phylogenetic relationships within the genus were inferred using 29 individuals belonging to the three known species, with additional sampling of two other closely-related genera, Muhtarophis and Lytorhynchus. We analysed three mitochondrial (12S, 16S, cytb) and one nuclear (c-mos) gene fragments. Phylogenetic trees were reconstructed using maximum likelihood and Bayesian inference methods; the latter method also used to provide the first time-calibrated molecular phylogeny of the genus. We generated a nuclear network and carried out a topology test and species delimitation analysis. Morphological comparisons were used to differentiate among species and to describe a new species from Israel. The studied material was comprised of 108 alcohol-preserved specimens, 15 photographs, and data from the literature for the examination of 17 mensural, 14 meristic, and two categorical characters.

RESULTS

The molecular results support Rhynchocalamus as monophyletic, and as having split from its sister genus Lytorhynchus during the Late Oligocene. The three recognized species of Rhynchocalamus comprise four independently evolving groups. The molecular results reveal that the genus began to diverge during the Middle Miocene. We revealed that the best-studied species, R. melanocephalus, is paraphyletic. A population, formally ascribed to this species, from the Negev Mountain area in southern Israel is phylogenetically closer to R. arabicus from Oman than to the northern populations of the species from Israel, Syria and Turkey. Herein we describe this population as a new species: Rhynchocalamus dayanaesp. nov.

DISCUSSION

We identify four species within Rhynchocalamus: R. satunini, R. arabicus, R. melanocephalus, and R. dayanaesp. nov., the latter, to the best of our knowledge, is endemic to southern Israel. The onset of Rhynchocalamus diversification is very old and estimated to have occurred during the Middle Miocene, possibly originating in the Levant region. Radiation probably resulted from vicariance and dispersal events caused by continuous geological instability, sea-level fluctuations and climatic changes within the Levant region.

Young relicts and old relicts: a novel palaeoendemic vertebrate from the Australian Central Uplands

Climatic change, and in particular aridification, has played a dominant role in shaping Southern Hemisphere biotas since the mid-Neogene. In Australia, ancient and geologically stable ranges within the vast arid zone have functioned as refugia for populations of mesic taxa extirpated from surrounding areas, yet the extent to which relicts may be linked to major aridification events before or after the Pliocene has not been examined in detail. Here we use molecular phylogenetic and morphological data to show that isolated populations of saxicoline geckos in the genus Oedura from the Australian Central Uplands, formerly confounded as a single taxon, actually comprise two divergent species with contrasting histories of isolation. The recently resurrected Oedura cincta has close relatives occurring elsewhere in the Australian arid biomes with estimated divergence dates concentrated in the early Pliocene. A new taxon (described herein) diverged from all extant Oedura much earlier, well before the end of the Miocene. A review of data for Central Uplands endemic vertebrates shows that for most (including Oedura cincta), gene flow with other parts of Australia probably occurred until at least the very late Miocene or Pliocene. There are, however, a small number of palaeoendemic taxa-often ecologically specialized forms-that show evidence of having persisted since earlier intensification of aridity in the late Miocene.

Assessing the diversity, host-specificity and infection patterns of apicomplexan parasites in reptiles from Oman, Arabia

Understanding the processes that shape parasite diversification, their distribution and abundance provides valuable information on the dynamics and evolution of disease. In this study, we assessed the diversity, distribution, host-specificity and infection patterns of apicomplexan parasites in amphibians and reptiles from Oman, Arabia. Using a quantitative PCR approach we detected three apicomplexan parasites (haemogregarines, lankesterellids and sarcocystids). A total of 13 haemogregarine haplotypes were identified, which fell into four main clades in a phylogenetic framework. Phylogenetic analysis of six new lankesterellid haplotypes revealed that these parasites were distinct from, but phylogenetically related to, knownLankesterellaspecies and might represent new taxa. The percentage of infected hosts (prevalence) and the number of haemogregarines in the blood (parasitaemia) varied significantly between gecko species. We also found significant differences in parasitaemia between haemogregarine parasite lineages (defined by phylogenetic clustering of haplotypes), suggesting differences in host–parasite compatibility between these lineages. ForPristurus rupestris, we found significant differences in haemogregarine prevalence between geographical areas. Our results suggest that host ecology and host relatedness may influence haemogregarine distributions and, more generally, highlight the importance of screening wild hosts from remote regions to provide new insights into parasite diversity.

Microendemicity in the northern Hajar Mountains of Oman and the United Arab Emirates with the description of two new species of geckos of the genus Asaccus (Squamata: Phyllodactylidae)

BACKGROUND

The Hajar Mountains of Oman and the United Arab Emirates (UAE) is the highest mountain range in Eastern Arabia. As a result of their old geological origin, geographical isolation, complex topography and local climate, these mountains provide an important refuge for endemic and relict species of plants and animals with strong Indo-Iranian affinities. Among vertebrates, the rock climbing nocturnal geckos of the genus Asaccus represent the genus with the highest number of endemic species in the Hajar Mountains. Recent taxonomic studies on the Zagros populations of Asaccus have shown that this genus is much richer than it was previously thought and preliminary morphological and molecular data suggest that its diversity in Arabia may also be underestimated.

METHODS

A total of 83 specimens originally classified as Asaccus caudivolvulus (including specimens of the two new species described herein), six other Asaccus species from the Hajar and the Zagros Mountains and two representatives of the genus Haemodracon were sequenced for up to 2,311 base pairs including the mitochondrial 12S and cytb and the nuclear c-mos, MC1R and ACM4 genes. Phylogenetic relationships were inferred using both Bayesian and maximum-likelihood approaches and the former method was also used to calibrate the phylogenetic tree. Haplotype networks and phylogenetic trees were inferred from the phased nuclear genes only. Sixty-one alcohol-preserved adult specimens originally classified as Asaccus caudivolvulus from the northern Hajar Mountains were examined for 13 morphometric and the five meristic variables using multivariate methods and were also used to diagnose and describe the two new species.

RESULTS

The results of the molecular and morphological analyses indicate that the species originally classified as Asaccus caudivolvulus is, in fact, an assemblage of three different species that started diversifying during the Mid-Miocene. The molecular phylogenies consistently recovered the Hajar endemic A. montanus as sister taxon to all the other Asaccus species included in the analyses, rendering the Arabian species of Asaccus polyphyletic.

DISCUSSION

Using this integrative approach we have uncovered a very old diversification event that has resulted in a case of microendemicity, where three morphologically and ecologically similar medium-sized lizard species coexist in a very short and narrow mountain stretch. Asaccus caudivolvulus is restricted to a small coastal area of the UAE and at risk from heavy development, while the two new species described herein are widely distributed across the northern tip of the Hajar Mountains and seem to segregate in altitude when found in close proximity in the Musandam Peninsula (Oman). Similarly to other integrative analyses of Hajar reptiles, this study highlights the high level of diversity and endemicity of this arid mountain range, underscoring its status as one of the top hotspots of reptile diversity in Arabia.

Development of 23 microsatellite loci for Boulenger’s agama (Agama boulengeri) with partial cross-amplification in other Agama species

Patterns of biodiversity and evolutionary processes controlling them are still poorly studied in desert biomes. Fine-scale markers could help answer some of the pressing research questions for desert biomes and Sahara in particular. Such markers are available for some large mammals and crocodiles, but not for small vertebrates. Here we present a battery of microsatellite loci developed for Agama boulengeri, a promising model to study evolutionary and demographic processes in the Sahara-Sahel. Loci were selected by sequencing enriched DNA libraries with 454 pyrosequencing. A total of 23 polymorphic loci were successfully amplified in four multiplex reactions. Cross-amplification of the microsatellite loci in A. agama and A. boueti was partially successful. These markers are a promising tool for assessing genetic diversity, gene-flow dynamics and demographic patterns in this group. Given the genus Agama is distributed throughout Africa, results presented here might also facilitate studies in other regions.