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The basic anatomy of the lacertid hemipenis (intromittent organ) and methods for its investigation are described. In many members of the Lacertidae, the hemipenis has a structure quite unlike that of other squamate reptiles: the distal lobes of the retracted organ are complexly folded and there is a well-defined supporting structure of dense connective tissue, the armature. This incorporates blood sinuses and has an intramuscular portion embedded in the m. retractor penis magnus and two club-shaped bodies, the clavulae, that support the lobes in the erect organ. Unarmatured hemipenes occur in some lacertids and, like those of other squamates, possess sac-like lobes in the retracted state, but they are singular in having the lobes invested by the m. retractor penis magnus. It is argued that many of these apparently primitive hemipenes are in fact secondary derivatives of the armatured type. There is considerable inter-specific variation in hemipenial structure which is described systematically. In some cases this involves differences in size, asymmetry and simplification, which may arise as physical isolating mechanisms and is useful in distinguishing otherwise very similar species, particularly in the genus Mesalina (p. 1253). Other shared derived hemipenial features provide useful information about relationships between species and higher taxa and a summary of the hypotheses that they support is given (p. 1254).

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A key and check list is provided to the 96 species and six additional subspecies of lizards and two species of amphisbaenians known to occur in and around Arabia. Philochortus neumanni, Lacerta jayakari, Lacerta cyanura, Latastia longicaudata andersonii, Mesalina guttulata, Mesalina olivieri, Mesalina martini, Mesalina brevirostris, Mesalina ayunensis, Mesalina adramitana, Acanthodactylus orientalis, Acanthodactylus robustus, Acanthodactylus opheodurus, Acanthodactylus boskianus, Acanthodactylus felicis, Acanthodactylus yemenicus, Acanthodactylus masirae, Acanthodactylus opheodurus, Acanthodactylus gongrorhynchatus, Acanthodactylus haasi, Acanthodactylus schmidti, Acanthodactylus blanfordii, Acanthodactylus arabicus, Acanthodactylus grandis, Acanthodactylus tilburyi, Acanthodactylus scutellatus hardyi.

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The structure of copulatory organs is used very widely in systematics, both for differentiating species and for working out relationships. Differences between taxa may arise from a variety of sources, including non-homology, differences in other parts of the animal, direct selection on copulatory organs, development of physical isolating mechanisms and pleiotropic events. Physical isolating mechanisms seem likely to account for the abrupt differences, involving size, asymmetry and simplifications, that are useful in distinguishing very similar lacertid species. Although these differences usually seem to arise at the end of a speciation event they can simultaneously be the initiating mechanism in a second one. Copulatory organs appear to have high inherent stability, probably resulting from frequent location in strongly homoeostatic environments, single function, insensitivity to niche shift and inertia due to the need to conform to the genitalia of the opposite sex. This stability may be overridden at times by direct selection on the organs themselves or pleiotropic events. Such changes tend to be retained because efficiency in copulation depends not on any absolute genital architecture but on close conformity of the organs. It is the combination of relative stability and tangible input of varied change, which tends to be retained, that so often makes these structures good indicators of relationship.

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Arabia, including the arid lowland regions of Jordan, Syria, Iraq and southwest Iran, has approximately 128 species of terrestrial reptiles and about 7 of amphibians. Endemicity is high, 55% of species being largely or entirely confined to the area. Abrupt faunal discontinuities are present between Arabia and neighbouring regions, namely the Horn of Africa, the Sahara desert and the relatively mesic areas to the north. However, there must have been substantial interchange with these areas in the past. Within Arabia, the main Zoogeographie division is between the arid regions occupying most of the peninsula and much smaller, often more mesic areas of endemicity in the south. The former are mainly occupied by Saharo-Sindian taxa and have rather more affinities with the Sahara than to arid regions east of Arabia. Southern areas of endemicity include: 1. The southwestern coast, with affinities to the Horn of Africa and the inland deserts of Arabia. 2. The southwest and southern highlands which share a number of forms with northeast African relationships but differ significantly, the former having more, often endemic species with African affinities and a number with relatives in the Mediterranean and other northern mesic regions. The drier southern mountains have their own endemics, some of which have representatives in the öiddat al-HaräsIs area to the east. 3. The north Oman mountains also possess distinctive species and populations, some of which are related to forms in the less arid parts of the Iranian area. Finally there are a number of mesic forms distributed around the periphery of Arabia, and populations at oasis sites in the arid region which are probably relicts of forms more widespread in Quaternary pluvial phases.

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In this study we review the species of lizards in the genus Mesalina (Lacertidae) and present a new key for their identification. We also obtained five photos of each species from the British Museum of Natural History that illustrate the dorsal, lateral (right and left), and ventral views of the head and the femoral pores of each species. The papers with the original descriptions of each species were reviewed and used in preparation of the key. Some remarks about the habitat, natural history, updated distribution map and previous taxonomic changes are explained.

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Aim We explored the phylogenetic relationships of species of Mesalina, using one nuclear and two mitochondrial loci. This genus of lacertid lizards is widely distributed in North Africa and the Middle East and our goal was to develop a scenario capable of explaining the current distribution and evolutionary patterns within the genus in the context of the wider historical biogeography of the region. Location North Africa and the Middle East. Methods The assembled dataset consisted of 193 Mesalina individuals, representing 12 species distributed across the geographical range of the genus. Bayesian and maximum likelihood methods were used to support phylogenetic inferences on two mitochondrial (cytochrome b and 16S ribosomal RNA) and one nuclear (beta-fibrinogen intron 7) markers. Palaeogeographical and palaeoclimatic data were used to support the inferred phylogeographical patterns. Results Mesalina lizards exhibit high genetic diversity and complex phylogenetic patterns, leading to an unsatisfactory systematic hypothesis of one paraphyletic and three polyphyletic traditional species. The estimated divergence times place the origin of the genus in the early Miocene (c. 22 Ma) and the divergence of most currently recognized species in the middle to late Miocene. The inferred ancestral distribution suggests that the genus and most of its species originated somewhere in Arabia or the Middle East, with the exception of the Mesalina olivieri complex, which may be of African origin. Main conclusions Phylogenetic reconstruction based on the three loci studied suggests a higher than expected cryptic diversity of Mesalina in North Africa and the Middle East. We suggest that the tectonic movements of the Arabian plate, coupled with the climatic changes occurring since the Miocene, may be responsible for the phylogeographical patterns of North African and Middle Eastern Mesalina.

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Herpetological research in Somalia dates from 1881 (G. Revoil`s Expedition) and progressively spread over most of the Somali territory thanks above all to the scientific missions conducted by R.H.R. Taylor (1929–34), G. Scortecci (1931, 1953, 1957) and, since 1959, by the University of Florence and the « Centro di Studio per la Faunistica ed Ecologia Tropicali » of the Consiglio Nazionale delle Ricerche (Florence, Italy). According to this list of the amphibians and reptiles reported to date for the Somali Democratic Republic, there are 27 species of amphibians, four of which (= 14.8%) are endemic; all these species belong strictly to the Ethiopian subregion sensu Darlington (1957). A monotypic genus, Lanzarana, is endemic. The reptiles are represented by at least 200 species. Excluding the marine species (six turtles and one snake), there are 194 species, of which 75 (= 38.6%) ar endemic to Somalia. Four genera are endemic: Xenagama (Agamidae), Haackgreerius gen. n. (Scincidae), Aeluroglena and Brachyophis (Colubridae). The majority of the Somali reptilian fauna is composed of species belonging strictly to the Ethiopian subregion sensu Darlington (1957): 164 species (= 84.5%). The remaining 30 species (= 15.5%) have a different, prevalently south-Mediterranean geonemy. Some reptiles inhabiting both Somalia and south-west Arabia confirm the well-known close biogeographic relationship existing between the two countries.

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Most herpetological research in Eritrea was conducted during the period 1827–1930 and was almost exclusively the preserve of Italian enthusiasts, who concentrated their efforts within an 80 km radius of Asmara. Virtually no field work has been undertaken on the Eritrean mainland in the past 65 years and a great deal still remains to be learned about the composition, distribution and status of the herpetofauna. The 109 species provisionally listed in the present work (Anura 19, Testudines 9, Crocodylia 1, Sauria 45, Serpentes 35) are predominantly savanna (37.5%) and deserticolous (33.1%) forms and the Eritrean highlands are impoverished by aridity. Of eight taxa which extend into this region from the Ethiopian Plateau, only three appear to be genuinely montane and the ability of the remainder to colonise lowland sites elsewhere in their ranges is taken as evidence of their resistance to drought conditions. Rhinotyphlops erythraeus (Scortecci 1928), which is known only from the type locality at an altitude of 2200 m, might conceivably be an Eritrean montane endemic, but the two nominally endemic anurans have no evident associations with high elevations and may therefore extend into neighbouring territories. The taxonomic status of Phrynobatrachus tellinii Peracca 1904 is very uncertain, but it has been possible to reach more definite conclusions about Rana cornii Scortecci 1929 and R. demarchii Scortecci 1929 following examination of the single surviving syntype of each species, recently rediscovered in London. The evidence from these specimens is that R. cornii is a junior synonym of Ptychadena schubotzi (Sternfeld 1917), while the name demarchii seems to represent a valid species which is most appropriately retained in the genus Rana (sensu DUBOIS 1992), at least until its relationships can be more satisfactorily determined on the basis of fresh material.

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This review lists Agama smithii Boulenger 1896 as a synonym of Agama agama (Linnaeus 1758), Agama trachypleura Peters 1982 as a synonym of Acanthocercus phillipsii (Boulenger 1895) and describes for the first time Acanthocercus guentherpetersi n. sp. Without more convincing evidence, Chamaeleon ruspolii Boettger 1893 cannot be accepted as specifically distinct from Chamaeleo dilepis Leach 1819, nor Chamaeleo calcaricarens Böhme 1985 from C. africanus Laurenti 1768. Consequently, 101 species of lizard are currently recognised in Ethiopia, of which some 40% appear to be denizens of the Somali-arid zone. This significant proportion is attributable in part to the importance of the Horn of Africa as a centre for reptilian diversification and endemicity, in part to the fact that this lowland fauna was rather extensively sampled during the 1930s, but also to the conspicuous neglect of lizards in other regions of the country. Mountain and forested habitats are widespread in Ethiopia, so it seems extraordinary to record only five saurian species which are believed to be endemic in such environments. The inference that there are many more still to be discovered has important implications for conservation, because montane forest is known to be among the most threatened of Ethiopian biomes and there is clearly an urgent need for its herpetofauna to be more thoroughly researched and documented.

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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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Taxonomic changes and new findings concerning the subfamily Eremiainae in Africa are summarized to update SZCZERBAK`s (1975) catalogue of the African Sand Lizards. Furthermore, a key to the species and subspecies of the genus Pedioplanis is provided.

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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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The herpetofauna of Wadi El Gemal National Park, Eastern Desert, Egypt currently includes 28 reptile species. Three large wadies, Wadi El Gemal, Wadi Abu Ghusoun and Wadi Sartout, were observed as a model of the spe- cies composition within the national park. Species assemblages, taxonomic and ecological diversity, and the biogeographical affinities of reptiles in the specific environment of the hyperarid desert are discussed.

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Aim: Deserts are generally perceived as areas of low diversity, and hence receive little attention from researchers and conservationists. Squamates are the dominant group of vertebrates in arid regions, and as such represent an ideal model to study biodiversity patterns in these areas. We examine spatial patterns of diversity, evolutionary history and endemism of terrestrial squamates of the Arabian Peninsula and test hypotheses on the role of topography and history of isolation so as to identify possible environmental drivers of diversification. Location: The Arabian Peninsula. Taxon: Squamate reptiles (Squamata; lizards and snakes). Methods: We generated distribution maps for all Arabian squamate species (including yet undescribed) and reconstructed their phylogenetic relationships using existing and newly produced genetic data for nearly all the species. We assessed patterns of the distribution of species richness, phylogenetic diversity and phylogenetic en demism across the peninsula to identify areas that could be considered evolutionary or endemicity hotspots for squamates. We evaluated community turnover across the peninsula and assessed the possible environmental drivers affecting the diversity of Arabian squamates in a regression framework. Results: The main hotspots of Arabian squamate diversity are mostly along the mountains that rim the peninsula while the most arid, central regions support a low diversity of species. The distribution of the phylogenetic diversity mirrors that of the species richness. Phylogenetic endemism is also highest in the mountains, especially when only endemic species are analysed. The deserts of northern Arabia are poor in terms of species richness and they show low connectivity to the peninsular communities. Topographic heterogeneity is the strongest predictor for Arabian squamates, followed by elevation. There is no correlation between richness and temperature. Main conclusions: The mountains of Arabia support rich and unique squamate communities that are dominated by local radiations of closely related and narrow-ranging species. In particular, the Asir Mountains of SW Arabia, Dhofar Province of Oman and the Hajar Mountains of northern Oman and UAE show unprecedented levels of squamate endemism and phylogenetic endemism. While many generalist species range across Arabia, a low number of species is shared between the peninsula and mainland Asia, indicating an effective isolation of the Arabian fauna. Squamate richness is highest in heterogeneous, topographically complex habitats.