×

Some 500 Dhofar reptiles and amphibians are discussed and a minimum of 48 terrestrial species recognised for the area of which 5 were previously undescribed; these are a gecko, Hemidactylus lemurinus, and the lacertids Acanthodactylus felicis, A. opheodurus,A. masirae and Mesalina ayunensis; a new subspecies of gecko from north Oman, Bunopus spatalurus hajarensis is also reported. Various other species are reviewed; it appears that Bunopus abudhabi is a synonym of B. blanfordi, which is probably conspecific with B. tuberculatus, Hemidactylus parkeri is regarded as a subspecies of H. turcicus, the Arabian agamas of the Agama cyanogaster group are shown to include 2 species to which the names adramitana and yemenensis are applicable although their status relative to African populations in the group is not clear; A. jayakari is conspecific with A. flavimaculata, and A. neumanni with A. sinaita; Chamaeleo chamaeleon orientalis is similar to more northern populations of C. chamaeleon but C. c. arabicus is very well differentiated and may be a separate species, the use of genitalia in the classification of Acanthodactylus is emphasised and A. arabicus, A. blanfordi and A. schmidti are all given full species status; the recognition of Mesalina as a genus indepemdemt of Eremias is confirmed, it is suggestes that Atractaspis engeddensis may be conspecific with A. microlepidota and that Lytorhynchus gaddi is a synonym of L. diadema; the distinctive population of Echis carinatus in Dhofar appears to be closely related to those in south-west Arabia and adjoining Africa but animals from northern Oman and the rest of south-west Asia are very different. Additional specimens are reported of Bunopus s. spatalurus and Coluber thomasi, both previously known from only 2 individuals. Geographical variations of a number of species is discribed including 3 geckos that show very considerable differences within southern Dhofar: Hemidactylus homocolepis, H. yerburii and Tropiocolotes scorteccii. Observations on the ecology of many species are noted, especially for the aberrant gecko genus Pristurus, one species of which, P. carteri, behaves like a small, ground-dwelling diurnal agamid. Resource partition, at least amongst the lizards, appears to be largely based on parameters of time, food (especially prey size), hunting method and space. A number of forms occourring in both noreth Oman and Dhofar show differences in niche in the two areas apparently related to the presence of absence of a competitor. Several species are recorded from Dhofar for the first time including Bunopus spatalurus, Hemidactylus flaviviridis, H. turcicus parkeri, Pristurus minimus, Agama adramitana, Acanthodactylus boskianus,Mabuya tessellata, Leptotyphlops macrorhynchus and Lytorhynchus diadema. The herpetofauna of the area can be divided into a largely northern element of desert-adapted forms widespread in the Arabian peninsula and a more peripheral element in the south which shows considerably more affinity to south-west Arabia than to northern Oman. No reptile of amphibian endemics occur in the forested areas of Dhofar but 3 species present in the drymesic habitats on the north side of the mountains may be restricted to the region. Acanthodactylus opheodurus, Acanthodactylus felicis, Acanthodactylus masirae, Acanthodactylus boskianus, Acanthodactylus schmidti, Mesalina adramitana, Mesalina ayunensis.

×

The ability to shed (autotomize) all or part of the tail, usually in response to predator attack, and often to subsequently regenerate it is widespread in lizards and amphisbaenians and also occurs in a few snakes and in the tuatara. Most species possess a sophisticated intravertebral autotomy mechanism which seems to be primitive in the Squamata. This appears to have been independently lost in members of many groups, but some agamids and snakes have regained the ability to shed their tails by a simpler intervertebral means and a -number of agamids have also redeveloped tail regeneration as well. Breakable tails are used to evade capture in two main ways: by enabling reptiles to break away from predators that have grasped them by the tail and by providing a distraction which deflects the attention of the attacker away from the vulnerable head and body. It is argued that loss of caudal autotomy has occurred when the costs of tail shedding outweigh its benefits. Likely costs include the expense of regrowing the tail and the loss of a variety of possible tail functions that may cause partial incapacitation, at least until the tail regenerates. Benefits of autotomy are liable to be low if predation is rare, if the animal is able to protect itself effectively in other ways, if it is too slow to evade further pursuit after the tail is shed, or if the tail is small or unpalatable and consequently not likely to distract a predator. Benefit variation may well be greater than cost variation and therefore more important in initiating the loss of autotomy mechanisms. Many taxa that do not shed the tail appear to conform to the above interpretation, but in some cases, such as the Platynota, Agamidae and Chamaeleonidae, lack of intravertebral autotomy may reflect the history of these groups rather than being a direct result of present ecological pressures. The distribution of intervertebral autotomy in the Agamidae suggests that it may have evolved only in rather special circumstances where tail fragility is advantageous even in the absence of the ability to regenerate. Restriction ot autotomy planes to the tail-base, so that the whole organ is lost, a condition found in a number of relatively slow-moving geckoes, is interpreted as a means of ensuring that enough of the tail is shed to distract a predator from further pursuit. The stimulus necessary to induce autotomy can vary rapidly in individual lizards and at least some of these changes probably maximize the effectiveness of the tail-shedding mechanism. Differences in the readiness with which all or part of the tail is shed exist between species and are likely to reflect the balance of costs and benefits in particular cases. Variations in incidence of broken tails between species and populations may be due to such differences in fragility but many other factors may play a part, including the age structure of samples, incidence of unsuccessful attacks by predators and ability to evade predators after autotomy. There is a clear tendency for climbing lizards, especially those living on rock surfaces, to have higher incidences of broken tails than ground-dwelling species, perhaps because the tail is usually less important in locomotion in the first group. Many lizards possess conspicuously coloured tails and tail movements that seem likely to help distract attention from the head and body. Conspicuous tail colouring is more frequent and often better developed in young animals, which tend to be more vulnerable than adults, and in active species from open habitats where crypsis may not always be very effective. Conspicuous tails usually have contrasting light and dark areas in nocturnal forms but are often a single bright colour in diurnal ones, probably reflecting the visual capacities of their respective predators. The predominance of blue tails in day-active species may be because this colour is striking close to but not very arresting at a distance, so it may not attract predators from far away while still drawing their attention at close quarters.

×

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.

×

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 tempera- ture 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 analy- ses 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 indi- cate 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).

×

Mitochondrial DNA sequences consisting of 645 sites from the 12S rRNA and 16S rRNA genes were used to estimate the phylogeny of 15 of the 32 species of spiny-footed lizards Acanthodactylus. The resultant tree has similarities to that produced from a differentially weighted data set of 32 morphological characters but there are also significant differences. However, combined analysis of molecular and morphological data sets produces the same tree topology as DNA sequence alone. The molecular data confirm that there are distinct eastern and western clades within Acanthodactylus, but place A. boskianus in the former while the A. scutellatus group constitutes a third clade. Species for which only morphological information is available were integrated with the combined tree to give a provisional phylogeny for 31 species. This phylogeny indicates that the ancestor of existing Acanthodactylus probably originated in south-west Asia and that North Africa was invaded by more than one lineage of the genus. It also suggests that soft aeolian sand habitats may have been independently occupied more than once. Molecular data provide independent evidence that the differential weighting of morphological characters in past analyses was appropriate.

×

The Afrotropical element in the Arabian herpetofauna is concentrated in the southwestern mountainous region, whereas everywhere else in the peninsula the reptile fauna is Saharo-Sindian. There is a high degree of correspondence between the reptile faunas of the Yemens and Somalia. A remarkable faunistic resemblance also exists between the relict faunas of SW Arabia and Morocco. Three evolutionary levels can be distinguished among Ethiopian taxa in Arabia and are interpreted as evidence of different times of faunal contact: 1. Old relicts (genus level) of a Palaeogene (pre continental drift) Arabian/North African fauna (Pristurus, Trogonophidae); 2. Endemic species closely related to East African species (most probably Miocene); 3. Species distributed on both sides of the Bäb al-Mandab (Pleistocene). Contrary to the Saharo-Sindian faunal elements, there is good evidence that groups 2 and 3 used a landbridge across the Bäb al-Mandab for faunal exchange: the Miocene closure of the southern outlet of the Red Sea and a Pleistocene land connection due to eustatic sea level change.

×

In this third paper on the herpetofauna of Oman, three families are treated: eleven Lacertidae, six Scincidae and one varanid. New records, notes on ecology and localities are combined with data from literature.

×

Observations concerning the ecology and distribution of the lacertid lizard species Acanthodactylus masirae and A. schmidti from southeastern Oman are reported along wi th new localities forA. masirae in the Wahiba Sands and in the Barr al Hikman. The herpetofauna found in the distribution areas of both species in Oman is presented.

×

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.

×

Die vorliegende Revision betrifft die Gattung Acanthodactylus (Damilie Lacertidae), die die Trocken- und Wüstengebiete des nördlichen Afrika und des südwestlichen Asiens bewohnt, mit Randpopulationen auf der Iberischen Halbinsel und auf Zypern. Mehr als 6000 Exemplare der Gattung, aus den bedeutendsten europäischen und amerikanischen Sammlungen, wurden untersucht. Zusätzlich wurden über 450 Röntgenaufnahmen für osteologische Untersuchungen ausgewertet. Die historische Übersicht behandelt in chronologischer Reihenfolge alle Arbeiten, die sich mit der Gattung Acanthodactylus beschäftigen, mit besonderer Berücksichtigung taxonomischer Studien. Ein beigegebener Bestimmungsschlüssel ermöglicht die Determination aller Arten der Gattung. Eine Reihe äußerer (Größe und Proportionen, Pholidose, Färbung und Zeichnung) und innerer (d.h. osteologischer) Merkmale wurde im Hinblick auf ihre Variabilität untersucht. Dann wurde ein Land ausgesucht, z.B. Ägypten, aus dem eine gute Materialbasis zur Verfügung stand. Für einen bestimmten Fundort in diesem Lande wurden sodann einige Kombinationen von Merkmalszuständen ermittelt, die sich aus dem Auftreten verschiedener Arten ergaben. Derselbe Vorgang wurde sodann auf den Rest Ägyptens übertragen, und die Merkmalskombinationen stellten sich als übereinstimmend heraus; sie erlaubten dadurch eine sichere Zuordnung von Tieren zu folgen Arten: A. boskianus, A. scutellatus und A. pardalis. Durch die Ausdehnung der Untersuchung nach Westen und Osten kamen weitere Taxa hinzu. Besonderer Aufmerksamkeit wurde diesen Merkmalskombinationen im Hinblick auf sympatrisches oder allopatrisches Auftreten der betroffenen Arten gezollt, mit dem Ergebnis, daß es in einigen Fällen möglich war, abzusichern, daß es sich um Populationen derselben Art handelt. Die Gattung Acanthodactylus wurde in mehrere Artengruppen gegliedert, die sich durch engere Beziehungen ihrer Arten untereinander auszeichnen. Die erste ist die micropholis-Gruppe mit der einzigen Art A. micropholis. Sie wird als die ursprünglichste der gesamten Gattung angesehen. Eine weitere Gruppe ist die boskianus-Gruppe, mit den Arten A. boskianus und A. schreiberi. Erstere wird ausführlich analysiert im Hinblick auf ihre außerordentlich große geographische Variabilität. Die yemenicus-Gruppe besiedelt die Arabische Halbinsel und besteht aus A. yemenicus sp.n., A. masirae, A. opheodurus und A. felicis. Eine weitere Gruppe ist die tristrami-Gruppe mit den Arten A. tristrami und A. robustus. Für erstere wird die Validität der Unterart orientalis verneint, die für iracensis dagegen bejaht. In die grandis-Gruppe wird hier nur A. grandis gestellt, während A. fraseri als dessen Synonym aufgefaßt wird. Die erythrurus-Gruppe enthält A. erythrurus, A. savignyi, A. blanci, A. boueti und A. guineensis. Letzterer rangierte bislang in der Gattung Eremias, gehört aber nach den hier vorgelegten Befunden in die erythrurus-Gruppe von Acanthodactylus. In der pardalis-Gruppe sind enthalten: A. pardalis, A. bedriagai, A. maculatus, A. spinicauda und A. busacki sp.n. aus Marokko. Die scutellatus-Gruppe besteht aus A. scutellatus, A. aureus, A. dumerili und A. longipes. Die letzte Gruppe ist die cantoris-Gruppe mit den Arten A. cantoris, A. arabicus, A. schmidti, A. blanfordi, A. gongrorhynchatus und A. haasi. Eine Bibliographie über die Gattung beschließt die Arbeit. Für jede Art werden Diagnosen, Verbreitungskarten, Synonymien, Beschreibungen und Materiallisten der untersuchten Tiere sowie auch Strichzeichnungen gegeben.

×

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.

×

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.