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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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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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Differences in surface structure (ober- hautchen) of body scales of lacertid lizards involve cell size, shape and surface profile, presence or absence of fine pitting, form of cell margins, and the occurrence of longitudinal ridges and pustular projections. Phylogenetic information indicates that the primitive pattern involved narrow strap-shaped cells, with low posteriorly overlapping edges and relatively smooth surfaces. Deviations from this condition produce a more sculptured surface and have developed many times, although subsequent overt reversals are uncommon. Like variations in scale shape, different patterns of dorsal body microornamentation appear to confer different and conflicting performance advantages. The primitive pattern may reduce friction during locomotion and also enhances dirt shedding, especially in ground-dwelling forms from moist habitats. However, this smooth microornamentation generates shine that may compromise cryptic coloration, especially when scales are large. Many derived features show correlation with such large scales and appear to suppress shine. They occur most frequently in forms from dry habitats or forms that climb in vegetation away from the ground, situations where dirt adhesion is less of a problem. Microornamentation differences involving other parts of the body and other squamate groups tend to corroborate this functional interpretation. Microornamentation features can develop on lineages in different orders and appear to act additively in reducing shine. In some cases different combinations may be optimal solutions in particular environments, but lineage effects, such as limited reversibility and different developmental proclivities, may also be important in their genesis. The fine pits often found on cell surfaces are unconnected with shine reduction, as they are smaller than the wavelengths of most visible light.

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In the central Namib desert (Southwest Africa), two morphologically very similar sibling species of lizards (Pediopllanis undata inornata, P. husabensis) live together along a parapatric distribution border. Especially the young specimens of both taxa are strikinly similar. Only P. husabensis takes young lizards of either species as prey, thus performing as a true `cannibal`, while P. u. inornata has developed a code of conduct, sparing is own young as well as those of the sibling species. A proposed advantage of the cannibalistic species in competitive coevolution is dicussed.

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In the course of a survey of the reptile fauna in the central Namib desert near the lower reaches of the rivers Khan and Swakop a yet undescribed lizard of the Pedioplanis undata complex was found to exist parapatrically with Pedioplanis undata inornata. Pro- nounced discontinuity of morphological and biochemical features of the specimens of the contact area proves that the new form is genetically sufficiently separated from Pedioplanis undata to be regarded as a species of its own {Pedioplanis husabensis n. sp.)

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A checklist of the lizards of the Cape Province, South Africa is presented. A total of 143 species and subspecies is recognized. The taxonomic status of no less than 84 (59,1%) of these has changed since the last review of the Cape lizards by FitzSimons (1943). Comments on the distribution and taxonomic status of problematic groups are included.

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The objectives of this study were to describe reproduction, diet, nematode infection and sexual dimorphism in Agama anchietae and Pedioplanis undata undata, two Namibian lizard species with wide geographic distributions for which such baseline ecological information is still lacking. The specimens used in the study came from the preserved Herpetological Collection of the National Museum of Namibia. Agama anchietae occupies rocky areas and the findings were as follows, reproduction: (i) it reproduces in spring and summer, the warm and rainy season of Namibia when insect food abounds, presumably to optimize the survival of its offspring, (ii) the gonads were inactive during autumn and winter, (iii) the mass of its abdominal fat bodies and liver decreased during the reproductive period, presumably because they serve as sources of energy during that time; diet: (i) prey items consumed by the sexes belonged to the orders Hymenoptera, Coleoptera, Lepidoptera and Mantodea, (ii) in addition to these an item belonging to the Diptera was also found in males, (iii) no significant numerical differences were found between the sexes with respect to the items consumed, (iv) the fact that hymenopterans occurred in substantially higher numbers suggest that the species relies mainly on sit-and-wait foraging; nematode infection: (i) in both sexes a larger number of nematodes occurred in the stomach than in the intestine, (ii) no significant numerical differences in infection were found between the sexes; sexual dimorphism: (i) males were larger than females in absolute body size, (ii) relative hind-limb but not forelimb length of males was significantly longer than that of females; (iii) relative head breath, length and width of males were all significantly greater than that of females. Pedioplanis undata undata occurs in flat open areas and the findings were as follows, reproduction: (i) a similar pattern with respect to the activity of the gonads as reported for A. anchietae above was also found in this species, (ii) the same also applied to the mass fluctuations of the abdominal fat bodies and the liver; diet: (i) males consumed items belonging to the orders Hymenoptera, Isoptera, Coleoptera, Lepidoptera, Blatoidea, Solifugida as well as larvae, (ii) in females the prey items belonged to the Hymenoptera, Orthoptera, Coleoptera, Hemiptera and Aranea, (iii) no significant numerical differences were found between the sexes for similar prey items, (iv) the low numbers of hymenopterans but fairly high diversity of prey types suggest that this species is a wide forager; nematode infection: (i) in both the stomach and intestine nematode infection was low with that of the stomach marginally higher than that of the intestine, (ii) no significant numerical differences were found between males and females; sexual dimorphism: (i) males and females were of similar body size, (ii) males had significantly longer fore-and hind-limbs than females, and may therefore be able to run faster, (iii) relative head breath, length and width of males were all significantly greater than that of females.

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Phylogenetic relationships among the 13 currently recognized species of Pedioplanis were analyzed using nuclear and mitochondrial DNA. Previous measures of species diversity within the genus appear to be underestimated, as novel, undescribed lineages were found within P. lineoocellata, P. namaquensis and the P. undata species complex. Further fine-scaled population genetic analyses were conducted to assess levels of genetic admixture, identify potential hybrid zones and uncover historical demographic patterns. Within P. lineoocellata, my results show that the three currently recognized subspecies do not represent independently evolving lineages. Further analyses suggest a South African origin of the species, with a subsequent northern expansion during the late Miocene. P. namaquensis appears to be comprised of two distinct and highly divergent lineages, furthermore the Orange River appears to represent a geographic barrier between them. Finally, interspecific relationships within the P. undata complex appear to be more complicated than previously thought as instances of paraphyly, polyphyly and several novel lineages were all revealed by the phylogenetic analyses.

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The lacertid genus Pedioplanis is a moderately speciose group of small-bodied, cryptically-colored lizards found in arid habitats throughout southern Africa. Previous phylogenetic work on Pedioplanis has determined its placement within the broader context of the Lacertidae, but interspecific relations within the genus remain unsettled, particularly within the P. undata species complex, a group largely endemic to Namibia. We greatly expanded taxon sampling for members of the P. undata complex and other Pedioplanis, and generated molecular sequence data from 1,937 bp of mtDNA (ND2 and cyt b) and 2,015 bp of nDNA (KIF24, PRLR, RAG-1) which were combined with sequences from GenBank resulting in a final dataset of 455 individuals. Both maximum likelihood and Bayesian analyses recover similar phylogenetic results and reveal the polyphyly of P. undata and P. inornata as presently construed. We con- firm that P. husabensis is sister to the group comprising the P. undata complex plus the Angolan sister species P. huntleyi + P. haackei and demonstrate that P. benguelensis lies outside of this clade in its entirety. The complex itself comprises six species including P. undata, P. inornata, P. rubens, P. gaerdesi and two previously undescribed entities. Based on divergence date estimates, the P. undata species complex began diversifying in the late Miocene (5.3 ± 1.6 MYA) with the most recent cladogenetic events dating to the Plio- cene (2.6 ± 1.0 MYA), making this assemblage relatively young compared to the genus Pedioplanis as a whole, the origin of which dates back to the mid-Miocene (13.5 ± 1.8 MYA). Using an integrative approach, we here describe Pedioplanis branchi sp. nov. and Pedioplanis mayeri sp. nov. representing northern populations previously assigned to P. inornata and P. undata, respectively. These entities were first flagged as possible new species by Berger-Dell’mour and Mayer over thirty years ago but were never formally described. The new species are supported chiefly by differences in coloration and by unique amino acid substitutions. We provide comprehensive maps depicting historical records based on museum specimens plus new records from this study for all members of the P. undata complex and P. husabensis. We suggest that climatic oscillations of the Upper Miocene and Pliocene-Pleistocene era in concert with the formation of biogeographic barriers have led to population isolation, gene flow restrictions and ultimately cladogenesis in the P. undata complex.

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Although reptile diversity in Africa is high, it is poorly represented in Angola, with just 257 species known. Despite its greater surface area and habitat diversity Angola has significantly lower lacertid lizard diversity than adjacent Namibia. This is particularly notable in African sand lizards (Pedioplanis), where 10 species (two endemic) are known from Namibia but only two are recorded from adjacent Angola. Pedioplanis benguelensis was described from Angola, but its taxonomic status is problematic and it was previously synonymised with P. namaquensis. All other Angolan Pedioplanis were referred to Namibian P. undata, although this taxon is now known to comprise a complex of at least five different species and the relationship of Angolan material to this complex has not been assessed. In this study, we investigated the phylogenetic placement of Angolan Pedioplanis using two mitochondrial (ND2 and 16S) and one nuclear (RAG-1) markers. A Bayesian analysis was conducted on 21 samples from Angola, combined with existing data for 45 individuals from GenBank and three additional samples from central Namibia. The phylogeny demonstrates that P. benguelensis is a valid species and that it is not the sister taxon to P. namaquensis with which it has been morphologically confused. In addition, Angolan lacertids previously referred to P. undata are not conspecific with any of the Namibian or South African species in that complex. Rather, there is strong support for the presence in Angola of additional species of Pedioplanis, which form a wellsupported sister clade to the P. undata complex (sensu stricto) of Namibia and two ofwhich are described herein. These discoveries highlight the need for further biodiversity surveys in Angola, as similar increases in species diversity in other Angolan taxa might be found given sufficient investment in biodiversity surveys.

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Most lacertids are active foragers, but intrafamilial variation in foraging mode is greater than in most lizard families. We collected data on eight species of African lacertids to assess this variation. Both active and ambush foraging occurred within Pedioplanis and Meroles. Meroles ctenodactylus had a proportion of time moving and proportion of attacked prey detected while moving intermediate to those for actively foraging and ambushing Pedioplanis, but its number of movements per minute was exceptionally high. This species has a unique mixed foraging mode. Like active foragers, it seeks food by tongue-flicking while moving and spends a high percentage of the time moving. Like ambush foragers, it searches visually for prey during pauses between movements. Our findings confirm published data on four Kalahari lacertids. We discuss the history of foraging modes in advanced lacertids.

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Comparative analyses were carried out about the variability of the pileal shields of different species belonging to the family Lacertidae. The results of the comparisons have been evaluated in respect to the phylogenetical relationships existing between the different genera and species of the family.

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Eremiadinae, one of three subfamilies of Lacertidae, are distributed throughout Asia and Africa. Previous phylogenetic studies suggested that one of the main groups of Eremiadinae (the Ethiopian clade) consist of two clades with predominately East-African and South-African distribution. Yet, especially the latter one, which includes the genera Pedioplanis, Meroles, Ichnotropis, Tropidosaura and Australolacerta, was not well supported in the molecular phylogenetic analysis. In this study, we analysed the phylogenetic relationships among the genera of the ‘South African clade’ to assess whether this group actually forms a highly supported clade and to address questions concerning the monophyly of the genera. We sequenced sections of the widely used mitochondrial genes coding for 16S rRNA, 12S rRNA and cytochrome b (altogether 2045 bp) as well as the nuclear genes c-mos, RAG-1, PRLR, KIF24, EXPH5 and RAG-2 (altogether 4473 bp). The combined data set increased the support values for several nodes considerably. Yet, the relationships among five major lineages within the ‘South African clade’ are not clearly resolved even with this large data set. We interpret this as a ‘hard polytomy’ due to fast radiation within the South African lacertids. The combined tree based on nine marker genes provides strong support for the ‘South African Clade’ and its sister group relationship with the ‘East African Clade’. Our results confirm the genus Tropidosaura as a monophylum, while Ichnotropis is paraphyletic in our trees: Ichnotropis squamulosa appears more closely related to Meroles than to Ichnotropis capensis. Furthermore, the monophyly of Meroles is questionable as well. Based on our results, I. squamulosa should be transferred from Ichnotropis into the genus Meroles. Also, the two species of Australolacerta (A. australis and A. rupicola) are very distantly related and the genus is perhaps paraphyletic, too. Finally we propose a phylogeographical scenario in the context of palaeoclimatic data and compare it with a previously postulated hypothesis.

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The available material of the collection of reptiles and amphibians collected and described from 1831 by Andrew Smith, is re-examined to determine in how far it may be regarded as typical. A complete list of the new species described by Smith, together with notes and comments pertaining thereto, is given. Illustrated with a plate on the type specimen of Pelusios sinuatis.

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An annotated checklist of indigenous and potentially indigenous Namibian terrestrial, aquatic and marine reptiles is presented. The purpose is to serve as an interim description of Namibian reptile diversity, to establish a taxonomic and biogeographical baseline, and as a preliminary review of the conservation status of Namibian reptiles. Two hundred and forty species of indigenous reptiles are presently known to occur in Namibia. These species comprise an array of approximately 265 described (but not always recognized) taxa, several of which are probably unwarranted. Species accounts are presented for all these species. Four accounts are for new species currently being described. Nineteen species have not yet been recorded from Namibia, but are expected to (accounts given) and another 6 species are less likely to occur (no accounts given). Full accounts are given for the 17 species which have been formally recorded in the past, but the lack of recent evidence suggests that the species is now locally extinct, the original report erroneous, or the species’ occurred as vagrants. Four additional species had been included on various published lists in the past, but have never been formally documented, no specimens are known to exist, and it is unlikely that the species would occur today even as vagrants (no accounts given). In total, 276 species-accounts are presented. Each account cites the original reference and type locality for each taxon, and a short description of the Namibian distribution. Emphasis is placed on Namibian and international legal and conservation status. Eighty-five species (33%) were found to be of local conservation concern. Gaps in knowledge (e.g. taxonomy, biogeography, and conservation status), where future research should be directed, are noted.

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In recent years there has been an exponential increase in the amount of published DNA sequences, as it has become one of the most popular sources of data for reconstructing phylogenies. A number of studies have attempted to resolve the relationships of groups of lacertids using mitochondrial DNA sequence data, in particular Podarcis and Gallotia (e.g. THORPE et al., 1994; 1996; GONZALEZ et al., 1996; FU et al., 1997; HARRIS, 1997; HARRIS et al., 1998a; 1999; CASTILLA et al., 1999a,b). Reassessment of these data suggest some alternative phylogenies to those previously published, and also highlight possible problems. Two studies have attempted to unravel the phylogeny of the whole family using mitochondrial DNA sequences (FU, 1998; HARRIS et al., 1998b). By combining these essentially congruent data sets, and reanalysing levels of support for the phylogenies produced, a more complete estimate of relationships across the family is produced. This is then compared to alternative sources of evidence, primarily morphological (ARNOLD, 1989), biochemical (MAYER & BENYR, 1994) and karyological (OLMO et al., 1993). Reasons for discrepencies are discussed, as are the relative advantages and disadvantages of the different sources of phylogenetic inference.

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DNA sequences from parts of the 12S, 16S and cytochrome b mitochondrial genes, which totalled 1049 aligned base pairs, were used to estimate the relationships of 49 species of Lacertidae, including representatives of 19 out of the 23 recognized genera and 23 species of the paraphyletic genus Lacerta. These data were used, together with morphological information, to estimate the relationships within the family. Molecular evidence corroborates the monophyletic status of many genera and species groups originally based on morphology. It indicates that Psammodromus forms a clade with Gallotia, which is the sister taxon of all other lacertids. These comprise three units: the primarily Afrotropical armatured group; the largely Oriental Takydromus; and the west Palaearctic Lacerta and its derivatives, Podarcis and Algyroides. Morphology also supports the first three assemblages, but suggests that they are derived from a paraphyletic Lacerta. Within Lacerta and its allies, DNA sequence analysis corroborates the affinity of some members of each of the subgenera Lacerta s. str. and Timon, and of the L. saxicola group. It also supports the relationship of L. monticola, L. bonnali and L. horvathi, and suggests that the L. parva–L. fraasi clade and L. brandti are not related to Psammodromus–Gallotia, as morphology indicates, but instead are associated respectively with the L. danfordi and L. saxicola groups. DNA sequence data provide additional evidence that the eastern Arabian `Lacerta` jayakari and `L.` cyanura are members of the armatured clade and also sister species. Our analysis supports an origin for present lacertids in west Eurasia. The armatured clade invaded Africa, probably in the mid-Miocene, spreading widely and evolving increasingly xeric-adapted forms, one lineage of which later moved back into the Palaearctic. `Lacerta` jayakari and `L.` cyanura are assigned to Omanosaura, Lutz and Mayer 1986. The name Gallotiinae Cano, Baez, Lopez-Jurado and Ortega, 1984 is available for the Gallotia–Psammodromus clade, Eremiainae Shcherbak 1975 for the armatured clade and Lacertinae for Lacerta, Podarcis and Algyroides. Two new subgenera of Lacerta are proposed here: Caucasilacerta for L. saxicola and its allies, and Parvilacerta for L. parva and L. fraasi.

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Namibia is mostly an arid and semi-arid country with a high number of reptile and fewer amphibian species. We review the herpetological literature dealing with Namibian species over the past fifty years, and provide up-to-date amphibian and reptile accounts using a widely accepted taxonomy and nomenclature. We critically discuss species accounts, draw attention to the historical development of species inventories for the country, and indicate species endemism for Namibia and the Namib Desert. In Namibia, the lizard families Gekkonidae, Lacertidae, and Scincidae have undergone adaptive radiations and are species-rich. This also applies to the snake family Psammophiidae. Areas of herpetological research that have received most attention are systematics (with its disciplines faunistics (area inventories), taxonomy, and phylogeny), ecology, and physiology. The former is indicative of early stages of herpetological research such as area inventories and the subsequent analyzes of the collections. The latter two were largely enabled by (1) species highly adapted to life in the hyper-arid Namib Desert, and (2) by the accessibility of these species in the Namib Desert through the infrastructure provided by the Gobabeb Research and Training Center. The majority of the eco-physiological research has focused on three highly psammophilus, diurnal lizard species; Meroles anchietae, M. cuneirostris, and Gerrhosaurus skoogi, whilst diverse geckos form the basis of eco-morphological studies. The concentration of research localities around cities and the Gobabeb Research and Training Center is characteristic for opportunistic research. Geographic centers of herpetological research have been the central Namib Desert (i.e. Gobabeb), and areas around Swakopmund and Windhoek. Extensive parts of Namibia remain barely touched. Herpetological publication frequency has been approximately the same since its beginning in the early 1800`s until the 1970`s. The period between 1986 and 2003 experienced a remarkable increase of publication activity that has slightly subsided around 2004 and picked up again in recent years. Recent conservation related studies investigate the impact of overgrazing with land degradation and water related issues such as canals and hydroelectric dam projects on herpetological communities. In the near future the impact of mining, especially Uranium mining in the Namib Desert, and the effects of climate change with the predicted drying and warming will demand increased attention. Advances in biotechnology with ever-increasing amounts of data and decreasing cost have and will progressively enable advances in traditional disciplines like taxonomy, phylogeny, and systematics. Additionally, these technologies will increasingly empower the newer disciplines of molecular ecology and conservation biology in Namibia. Annotated, updated species checklists highlight Namibian and Namib diversity and endemicity, and also direct researchers to the numerous taxonomic problems that still confound full understanding of the region`s herpetofauna.

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The evolutionary diversification of many terrestrial vertebrate groups is strongly linked to climatic events in the Cenozoic, the period from 65 Million years ago to today when modern animals first appeared. I investigated the effects of Cenozoic climate change on the taxonomic and morphological diversification of the Old World lizard family Lacertidae, with particular emphasis on the African radiation. African lacertids exhibit an unusual pattern of diversification, in which their highest species richness occurs in deserts north and south of the equator, despite being spread throughout the continent. This disparity is particularly surprising given that desert lacertids are thought to be evolutionarily younger than their mesic-dwelling relatives, suggesting increased diversification rates in arid habitats. To identify the evolutionary factors underlying this pattern, I use a combination of phylogenetic, morphological and ecological techniques. In Chapter 1, I apply Bayesian methods and fossil-based calibrations to molecular sequence data to construct a time-calibrated phylogeny for Lacertidae. I estimate that the family arose in the early Cenozoic, with the majority of their African radiation occurring in the Eocene and Oligocene. In Chapter 2, I describe changes in lacertid body shape across biomes and substrates, and find widespread morphological convergence in similar habitat types. I suggest that in addition to foraging demands, fluctuating and extreme climatic conditions, largely driven by precipitation and temperature, contribute to morphological convergence across independent arid-dwelling clades. Finally, I test if ancestral transitions in ecology, morphology, and rates of diversification temporally coincide with paleoclimatic events in the Cenozoic. I use High Resolution X-ray Computed Tomography to characterize changes in the skull related to life in arid habitats, and apply maximum likelihood methods to test if the origins of those traits temporally coincide with significant shifts in habitat, diversification rates and climatic changes. My results show that African lacertids experienced three major peaks in diversification, accompanied by the evolution of suites of arid-adapted morphological traits. These changes coincide with climatic shifts in Africa, including the transition from closed forests to open grasslands and savanna in the late Oligocene, prior to the peak temperatures of the mid-Miocene Climatic Optimum, and following the formation of the Benguela current leading to hyper-aridity in southern Africa. I conclude that deserts are important centers for reptile evolution, but that expected changes in climate due to global warming may outpace the ability of arid-dwelling species to adapt and persist in the future.

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Knowledge of the thermal ecology of a species can improve model predictions for temperatureinduced population collapse, which in light of climate change is increasingly important for species with limited distributions. Here, we use a multi-faceted approach to quantify and integrate the thermal ecology, properties of the thermal habitat, and past and present distribution of the diurnal, xeric-adapted, and active-foraging Namibian lizard Pedioplanis husabensis (Sauria: Lacertidae) to model its local extinction risk under future climate change scenarios. We asked whether climatic conditions in various regions of its range are already so extreme that local extirpations of P. husabensis have already occurred, or whether this micro-endemic species is adapted to these extreme conditions and uses behavior to mitigate the environmental challenges. To address this, we collected thermoregulation and climate data at a micro-scale level and combined it with micro- and macroclimate data across the species’ range to model extinction risk. We found that P. husabensis inhabits a thermally harsh environment, but also has high thermal preference. In cooler parts of its range, individuals are capable of leaving thermally favorable conditions—based on the species’ thermal preference—unused during the day, probably to maintain low metabolic rates. Furthermore, during the summer, we observed that individuals regulate at body temperatures below the species’ high thermal preference to avoid body temperatures approaching the critical thermal maximum. We find that populations of this species are currently persisting even at the hottest localities within the species’ geographic distribution. We found no evidence of range shifts since the 1960s despite a documented increase in air temperatures. Nevertheless, P. husabensis only has a small safety margin between the upper limit of its thermal preference and the critical thermal maximum and might undergo range reductions in the near future under even the most moderate climate change scenarios.

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Reptiles are supposed to be relatively invulnerable to the ongoing rapid anthropogenic climate change as they are able to actively regulate their body temperature (Tb) through behaviour, tolerate high Tb and resist water loss. However, recent studies have shown that lizards and snakes seem to be more at risk than previously expected. In Mexico, increased local extinction probability in lizards correlated with the magnitude of warming during the reproductive period, questioning the assumption of climate invulnerability. We tested the hypothesis that different lizard species of the family Lacertidae are vulnerable to rises in maximum temperatures in Namibia, especially in the Namib and the Kalahari. We predicted that inhabiting different habitats with different microhabitat temperatures and different preferred Tb within different distribution ranges would result in differences in local extinction probability. As opposed to other studies our model integrates past and present distributions verified by museum collections and ground-truthed, a quantifiable physiological parameter (preferred body temperature Tpref) and available operative temperatures in correlation to air temperatures. Data was collected for 17 species (Meroles anchietae, M. cuneirostris, M. suborbitalis, M. ctenodactylus, M. reticulatus, M. micropholidotus, M. knoxii, Pedioplanis namaquensis, P. laticeps, P. lineoocellata, P. breviceps, P. rubens, P. undata, P. inornata, P. gaerdesi, P. husabensis and Heliobolus lugubris). Our first results seem to indicate that populations of at least one of the tested species were extirpated (both predicted by the model and verified) in the hottest area of its distribution range due to increased maximum temperatures during the reproductive season since the mid-1970s. Furthermore, different extents in future extinction risk are predicted under consideration of the currently accepted climate change scenarios. It seems that Namibian Lacertidae under current conditions already live at their thermal maximum.

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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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In both December 1992 and September 1995 I travelled through South Africa and Namibia. In the Daan Viljoen park in Windhoek Agama planiceps, Mabuya spilogaster and Pachydac- tylus bibroni were found. Pedioplanis brevi- ceps was seen in trees and bushes of the Namib Desert while in the barer valleys Pedioplanis undata undata was observed. A Chamaeleo namaquensis was seen in a small bush. Other species which were recorded were M. spilogaster and Ptenopus garrulus macula- Ius. In the Kalahari Gemsbokpark only M. spi- logaster, Agama aculeata aculeata and Pelomedusa subrufa were seen, the latter after a shower. Pedioplanis undata inomata, Mabuya sulcata, Mabuya variegata, Platysaurus capensis, Agama anchietae, Pedioplanis namaquensis, Cordylus po/yzonus and Pachydactylus bibroni were found in Fish River Canyon by the camp site. The tempera- ture can rise to 45°C over the day. The lizards seemed to go into shock when captured. In 1995 I spent a long time in Namaqualand. Here a lot of reptiles were found in a relative- ly small area. These included: Cordylus cataphractus, Cordylus polyzonus, Pediopla- nis lineocellata pulchella, Meroles suborbi- talis, Agama hispida hispida, Bitis arietans, Homopus signatus signatus and Chersina angulata. In the Mediterranean climatic zone and in the Karoo the following unusual species were recorded: Psammo- bates tentorius trimeni, Geochelone parda- lis and Pseudocordy/us capensis.

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The diversity of lacertid lizards in Africa is highest in the southern African subcontinent, where over two-thirds of the species are endemic. With eleven currently recognized species, Pedioplanis is the most diverse among the southern African genera. In this study we use 2200 nucleotide positions derived from two mitochondrial markers (ND2 and 16S rRNA) and one nuclear gene (RAG-1) to (i) assess the phylogeny of Pedioplanis and (ii) estimate divergence time among lineages using the relaxed molecular clock method. Individual analyses of each gene separately supported different nodes in the phylogeny and the combined analysis yielded more well supported relationships. We present the first, well-resolved gene tree for the genus Pedioplanis and this is largely congruent with a phylogeny derived from morphology. Contrary to previous suggestions Heliobolus/Nucras are sister to Pedioplanis. The genus Pedioplanis is monophyletic, with P. burchelli/P. laticeps forming a clade that is sister to all the remaining congeners. Two distinct geographic lineages can be identified within the widespread P. namaquensis; one occurs in Namibia, while the other occurs in South Africa. The P. undata species complex is monophyletic, but one of its constituent species, P. inornata, is paraphyletic. Relationships among the subspecies of P. lineoocellata are much more complex than previously documented. An isolated population previously assigned to P. l. pulchella is paraphyletic and sister to the three named subspecies. The phylogeny identifies two biogeographical clades that probably diverged during the mid-Miocene, after the development of the Benguella Current. This probably led to habitat changes associated with climate and, in conjunction with physical barriers (Great Escarpment), contributed towards speciation within the genus Pedioplanis.

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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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The albumins from 41 species of the family Lacertidae representing a substantial part of genera as well as infrageneric groups of the collective genus Lacerta s.l. were investigated by means of the MCF technique. The data allow a chronological estimation of the most important radiation events and their correlation with paleogeographical facts. Our results are in remarkable contradiction to the phylogeny presented by ARNOLD (1989a) based mainly on morphological characters. The most important phylogenetic relationships are: 1. The genera Gallona and Psammodromus are already isolated from the other taxa since the Oligocene. We assess these main branches as subfamilies Gallotiinae and Lacertinae. 2. Lacerta s.str. and Lacerta subgenus Zootoca form the sister group of the remaining Lacertinae. 3. A colonization of Africa in the Lower Miocene has led to a separation in two lines, with mainly Eurasian and African members respectively. 4. ARNOLD`S (I.e.) `Ethiopian and advanced Saharo-Eurasian clade` proved to be a paraphyletic unit, one group of genera being more closely related to European taxa. All techniques applied to the systematics of Lacertidae hitherto are critically discussed. An area-time- hypothesis concerning the phylogeny of Lacertidae is presented. Key words: Lacertidae, phylogeny of; Gallotiinae subfam. nov.; Lacertinae subfam. nov.; micro complement fixation; albumin evolution.

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13 species of the genera Aporosaura, Meroles, Pedioplanis, and Heliobolus horn Namibia and additionally Pedioplanis burcheUi from the Republic of South-Africa have been investigated proteinelectrophoretically concerning 14 genetic loci. Pedioplanis and Meroles turned out to be sister groups, Heliobolus and Aporosaura are standing further apart. The su bgenera of Meroles (Meroles s. str. and Saurites) could not be parted distinctly. The morphological correspondence between Aporosaura and Saurites has been interpreted as convergent adaptions to their habitat.

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The family Lacertidae encompasses more than 250 species distributed in the Palearctis, Ethiopis and Orientalis. Lacertids have been subjected in the past to several morphological and molecular studies to establish their phylogeny. However, the problems of convergent adaptation in morphology and of excessively variable molecular markers have hampered the establishment of well supported deeper phylogenetic relationships. Particularly the adaptations to xeric environments have often been used to establish a scenario for the origin and radiation of major lineages within lacertids. Here we present a molecular phylogenetic study based on two nuclear marker genes and representatives of 37 lacertid genera and distinct species groups (as in the case of the collective genus Lacerta). Roughly 1600 bp of the nuclear rag1 and c-mos genes were sequenced and analyzed. While the results provide good support to the hitherto suggested main subfamilies of Gallotiinae (Gallotia and Psammodromus), Eremiainae and Lacertinae [Harris, D.J., Arnold, E.N., Thomas, R.H., 1998. Relationships of lacertid lizards (Reptilia: Lacertidae) estimated from mitochondrial DNA sequences and morphology. Proc. R. Soc. Lond. B 265, 1939–1948], they also suggest unexpected relationships. In particular, the oriental genus Takydromus, previously considered the sister-group to the three subfamilies, is nested within Lacertinae. Moreover, the genera within the Eremiainae are further divided into two groups, roughly corresponding to their respective geographical distributions in the Ethiopian and the Saharo-Eurasian ranges. The results support an independent origin of adaptations to xeric conditions in different subfamilies. The relationships within the subfamily Lacertinae could not be resolved with the markers used. The species groups of the collective genus Lacerta show a bush-like topology in the inferred Bayesian tree, suggesting rapid radiation. The composition of the subfamilies Eremiainae and Lacertinae as well as their phylogeography are discussed.

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Die Wüstenrenner-Eidechsen Namibias werden derzeit in folgende vier Gattungen eingeteilt: Pedioplanis, Meroles, Aporosaura und Heliobolus. Während zweier Reisen konnten sie im Freiland studiert werden. Im Terrarium wurden sieben Arten gehalten, von denen vier Arten nachgezüchtet werden konnten. Neben Pedioplanis rubens, P. lineoocellata pulchella und P. namaquensis erweist sich vor allem Meroles cuneirostris als ein sehr gut zu haltendes, interessantes Terrarientier.

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Lizards are a diverse clade in which one radiation consists entirely of sit-and-wait foragers and another consists of wide foragers. Lizards utilizing these two foraging modes are known to differ in diet, but little is known about how feeding morphology relates to diet and/or foraging mode. This study tested the hypothesis that skull morphology and biting performance are related to diet preference, and consequently, coevolve with foraging mode. Four species of lacertid lizard were studied because they vary in foraging mode, their phylogenetic relationships are known and they are well studied ecologically. Using an ‘ecomorphological’ approach, skull morphology and biting performance were quantified and mapped on to the phylogeny for the species. The results indicate that sit-and-wait species have shorter, wider skulls than the wide foraging species, and that all are significantly different in overall head shape. The sit-and-wait species had similar values for biting performance; however, clear phylogenetic patterns of covariation were not present between sit-and-wait and wide foraging species for either biting performance or skull morphology. Thus, skull morphology and performance have little influence on diet and foraging mode in these species. Instead it is likely that other factors such as seasonal prey availability and/or life history strategy shape foraging mode decisions.

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ush encroachment is a serious environmental and economic problem in Namibia, but little is known about impacts on native reptile diversity. Area-confined visual surveys were used to examine a diurnal lizard assemblage in central Namibian commercial ranchlands. Surveys were conducted in plots of open savanna habitat and proximal bush-encroached habitat. The following four species comprised 97.5% of all lizard observations: Pedioplanis undata, Mabuya varia, M. striata, and Lygodactylus bradfieldi. Pedioplanis undata was terrestrial, and the remaining three species were largely arboreal in our study plots. Mabuya varia was found in all savanna plots but was absent from all bush-encroached plots. Two species (P. undata and L. bradfieldi) were less abundant in bush-encroached plots. One species (M. striata) was more abundant in bush-encroached plots than in open savanna plots. Arboreal lizards demonstrated an avoidance to invasive woody plant species. Decreased diversity of habitat structure in bush-encroached habitats appears to influence native savanna lizard assemblages. Our results are consistent with accumulating evidence suggesting that bush encroachment and its associated ecological impacts are reorganizing savanna ecosystems throughout southern Africa.

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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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As new details on the reproduction of Pedioplanis undata inornata and P. husabensis, the laying of single eggs and a very short incubation time are reported.

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The present paper of N. N. SZCZERBAK was originally published in Russian as `Katalog afrikanskih Jascurok` by the Academy of Sciences, Institute of Zoology, Museum of Zoology, USSR, Kiev (83 pp., 30 maps) in 1975. Lists of synonyms, bibliography, maps and table of contents - all being parts of the original paper - have not been included in this translation which was carried out with the consent of the author by R. GÜNTHER (Berlin) and H. GRILLITSCH (Vienna). The English summary was taken over as provided in the original version. As a SHORT NOTE in this issue of HERPETOZOA subsequent to the translation comments and updated addenda by W. MAYER are provided indicated by [aa* bb* etc.] in the text.

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Evolutionary changes in foraging style are often believed to require concurrent changes in a complex suite of morphological, physiological, behavioural and life-history traits. In lizards, species from families with a predominantly sit-and-wait foraging style tend to be more stocky and robust, with larger heads and mouths than species belonging to actively foraging families. Here, we test whether morphology and foraging behaviour show similar patterns of association within the family Lacertidae. We also examine the association of bite force abilities with morphology and foraging behaviour. Lacertid lizards exhibit considerable interspecific variation in foraging indices, and we found some evidence for a covariation between foraging style and body shape. However, the observed relationships are not always in line with the predictions. Also, the significance of the relationships varies with the evolutionary model used. Our results challenge the idea that foraging style is evolutionarily conservative and invariably associated with particular morphologies. It appears that the flexibility of foraging mode and its morphological correlates varies among lizard taxa.