×

Abstract The Equatorial African group of lacertids comprises nine species which share a number of derived features and appear to constitute a holophyletic assemblage. Revision of the group using morphological characters analyzed by parsimony and compatibility methods results in the following taxonomic changes: Lacerta jacksoni = Adolfus jacksoni, Lacerta echinata = Gastropholis echinata, Bedriagaia tropidopholis = Gastropholis tropidopholis, Bedriagaia moreavi = Gastropholis prasina, the latter species being validated and removed from the synonymy of Gastropholis vittata. Adolfus jacksoni has most features in common with the hypothetical ancestor of the group, while Holaspis guentheri and the species of Gastropholis are the most derived forms. Geographical variation in Adolfus alleni is described and what is known of the ecology of the Equatorial group summarized. Most are forest dwellers with the majority of the more primitive forms living on tree boles and among litter and timber on the forest floor (Adolfus jacksoni, A. africanus, A. vauereselli). Another, Holaspis guentheri, is confined to tree boles but glides between them, while the species of Gastropholis appear to be climbers in flimsy vegetation and Adolfus alleni is ground-dwelling above the tree line. Many of the morphological features characterizing these lizards appear to be functionally related to their particular habitats.

×

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.

×

A complete catalogue is provided for the type specimens of lacertid lizards in the herpetological collection of the Zoological Museum, Berlin, as of December, 1993. The collection contains a total of 514 type specimens, representing 63 taxa, of which 42 are currently regarded as valid at the specific or subspecific level. Types representing an additional four taxa appear to have been lost from the collection. The collections are especially rich in African lacertid types and in historically significant specimens collected early in the Nineteenth Century by Pallas, Eversmann, and Hemprich & Ehrenberg. Also present are the type series of many subspecies of Podarcis lilfordi and P. pityusensis described by Eisentraut.

×

A phylogenetic-comparative approach was used to assess and refine existing secondary structure models for a frequently studied region of the mitochondrial encoded large subunit (16S) rRNA in two large lizard lineages within the Scincomorpha, namely the Scincidae and the Lacertidae. Potential pairings and mutual information were analyzed to identify site interactions present within each lineage and provide consensus secondary structures. Many of the interactions proposed by previous models were supported, but several refinements were possible. The consensus structures allowed a detailed analysis of rRNA sequence evolution. Phylogenetic trees were inferred from Bayesian analyses of all sites, and the topologies used for maximum likelihood estimation of sequence evolution parameters. Assigning gamma-distributed relative rate categories to all interacting sites that were homologous between lineages revealed substantial differences between helices. In both lineages, sites within helix G2 were mostly conserved, while those within helix E18 evolved rapidly. Clear evidence of substantial site-specific rate variation (covarion-like evolution) was also detected, although this was not strongly associated with specific helices. This study, in conjunction with comparable findings on different, higher-level taxa, supports the ubiquitous nature of site-specific rate variation in this gene and justifies the incorporation of covarion models in phylogenetic inference.

×

Currently, four species of the lacertid lizard genus Adolfus are known from Central and East Africa. We sequenced up to 2825 bp of two mitochondrial [16S and cytochrome b (cyt b)] and two nuclear [(c-mos (oocyte maturation factor) and RAG1 (recombination activating gene 1)] genes from 41 samples of Adolfus (representing every species), two species each of Gastropholis and Holaspis, and in separate analyses combined these data with GenBank sequences of all other Eremiadini genera and four Lacertini outgroups. Data from DNA sequences were analysed with maximum parsimony (PAUP), maximum-likelihood (RAxML) and Bayesian inference (MrBayes) criteria. Results demonstrated that Adolfus is not monophyletic: Adolfus africanus (type species), Adolfus alleni, and Adolfus jacksoni are sister taxa, whereas Adolfus vauereselli and a new species from the Itombwe Plateau of Democratic Republic of the Congo are in a separate lineage. Holaspis and Gastropholis were recovered in separate clades. Based on these molecular data, relatively substantial sequence divergence, and multiple morphological differences, we describe a new genus of lacertid for the lineage including A. vauereselli and the new Itombwe species. The recognition of this new, endemic genus underscores the conservation importance of the Albertine Rift, especially the Itombwe Plateau, a unique region that is severely threatened by unchecked deforestation, mining, and poaching.

×

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.

×

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.

×

This paper presents the composition of the lizard fauna of Maringa-Lopori-Wamba landscape in the western portion of the central Congo basin in the Democratic Republic of the Congo and its weak similarity with the lizard fauna of Gaboon and Ituri faunal areas. It also fills a gap of knowledge in a region where no previous research on Sauria has been undertaken and signals the presence of Leptosiaphos hylophilus and Lygodactylus n. sp. The paper mentions the finding of a subspecies of Gastropholis echinata. These data are important since collected for the first time in a spot where no herpetological research on lizards has previously been undertaken.

×

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.

×

Many animals display complex colour patterns that comprise several adjacent, often contrasting colour patches. Combining patches of complementary colours increases the overall conspicuousness of the complex pattern, enhancing signal detection. Therefore, selection for conspicuousness may act not only on the design of single colour patches, but also on their combination. Contrasting long- and short-wavelength colour patches are located on the ventral and lateral surfaces of many lacertid lizards. As the combination of long- and short-wavelength-based colours generates local chromatic contrast, we hypothesized that selection may favour the co-occurrence of lateral and ventral contrasting patches, resulting in complex colour patterns that maximize the overall conspicuousness of the signal. To test this hypothesis we performed a comparative phylogenetic study using a categorical colour classification based on spectral data and descriptive information on lacertid coloration collected from the literature. Our results demonstrate that conspicuous ventral (long wavelength-based) and lateral (short wavelength-based) colour patches co-occur throughout the lacertid phylogeny more often than expected by chance, especially in the subfamily Lacertini. These results suggest that selection promotes the evolution of the complex pattern rather than the acquisition of a single conspicuous colour patch, possibly due to the increased conspicuousness caused by the combination of colours with contrasting spectral properties.

×

Herein is presented a list of the reptiles and anurans from the Parc National des Volcans (PNV) (01°43’ S, 29°52’ W), an area in the west and north provinces of the Republic of Rwanda in the Albertine Rift region of Africa. Fieldwork was conducted between two and six days per week from June through August 2007 and 2008. We also conducted literature searches of all historical expeditions within the park for species records. Seventeen species of reptiles and anurans are recorded from the PNV. Nine of the species were anurans, distributed in five families: Arthroleptidae (3), Bufonidae (1), Hyperoliidae (3), Phrynobatrachidae (1), and Pipidae (1). Eight species of reptiles were recorded from five families: Chamaeleonidae (1), Lacertidae (2), Scincidae (2), Colubridae (2), and Viperidae (1). Eight of the seventeen species found in the PNV are endemic to the Albertine Rift.

×

Includes bibliographical references and index. Introduction. List of localities. New genus. List of new species and type localities. Preliminary note on the distribution of African lizards. Note on the distribution of African turtles -- Testudinata. Testudinae. Kinixys Bell. Pelomedusidae. Pelusios Wagler. Pelomedusa Wagler -- Loricata (Crocodilia). Crocodylidae. Crocodylus Laurenti. Osteoblepharon, new genus. Ecological notes on Congo crocodiles -- Squamata. Lacertilia. Geckonidae. Gonatodes Fitzinger. Hemidactylus Cuvier. Lygodactylus Gray. Agamidae. Agama Daudin. Varanidae. Varanus Merrem. Lacertidae. Lacerta Linnaeus. Bedriagaia Boulenger. Algiroides Fitzinger. Ichnotropis Peters. Eremias Wiegmann. Holaspis Gray. Gerrhosauridae. Gerrhosaurus Wiegmann. Scincidae. Mabuya Fitzinger. Lygosoma Gray. Ablepharus Fitzinger. Anelytropidae. Feylinia Gray. Chamaeleontidae. Chamaeleon Gronovius. Rhampholeon Günther -- Appendix A: Lists of the turtles, crocodiles, lizards, and chameleons of the rain forest and of the Sudanese subprovince -- Appendix B: Notes on the types of Hallowell`s West African species in the Academy of Natural Sciences of Philadelphia.

×

The aim of this study was to determine if divergence in habitat use among lacertid lizards is paralleled by morphological differentiation. For 35 lacertid species, we measured body, head and limb dimensions. Habitat use was inferred from the literature: ground-dwelling on open terrain, ground-dwelling in vegetated areas, shrub-climbing, tree-climbing, saxicolous (i.e. rock-climbing). Traditional (i.e. non-phylogenetic) statistical analyses suggest morphological differences among species groups with different habitat use. Ground-dwelling species from open habitats tend to have longer femurs, tibiae and humeri (relative to body length) than other groups. Cursorial (i.e. level-running) species have relatively high heads and trunks compared to climbing species. These differences follow biomechanical predictions and it is tempting to consider tham as adaptations to habitat use. However, phylogenetic analyses of the data fail to establish a clear relationship between habitat use and morphology in the data set considered. There is a weak indication that the differences in head and trunk height have evolved as an adaptation to different habitat use, but the differences in relative limb dimensions among species groups with different habitat use vanish. Either adaptation of limb dimensions to habitat use has not occurred in lacertid lizards, or our methods are unable to demonstrate such an adaptation. We show that uncertainties in the topology of the phylogenetic tree used are unlikely to influence the outcome of our study. We also address the fact that habitat use is often similar in different branches of the phylogenetic tree, and the consequences this may have for the power of our statistical analyses.

×

This study lists the amphibian and reptile species of Kibale National Park, Uganda, and discusses the natural history and biogeography of this unique herpetofauna. This herpetofaunal inventory was compiled based upon literature records and collections made during 17 mo fieldwork between 1995 and 1997, and includes 28 anuran, 15 lizard, and 32 snake species. Faunal comparisons with seven other tropical African forests show a high degree similarity between the Kibale herpetofauna and those of central and West Africa.

×

The amphibians and reptiles of Kibale National Park in western Uganda were inventoried over an 18-mo period in 1995 and 1996-97. A total of 75 species, including 28 amphibians and 47 reptiles, were collected or observed. Comparison with other equatorial African herpetofaunas confirms that the Kibale fauna is most similar to those of southwest Uganda and eastern Congo-Zaire, both hypothesized Pleistocene forest refugia. Comparison with a West Africa fauna also shows a fair degree of overlap, while almost no overlap was observed between Kibale and the forests of coastal East Africa. This confirms that the Kibale herpetofauna is an extension of the Guinea-Congolean forest faunas. Randomly placed 5 x 5 m plots were used to sample the herpetofauna of the forest leaflitter layer in unlogged forest, logged forest, and a neighboring exotic pine plantation. A total of 18 amphibian and reptile species were captured in the litter, a number similar to that observed in mid-elevation tropical forests in Central America and Southeast Asia. Density at Kibale was much lower than most previous studies. Analysis of the feeding ecology of the most abundant litter species showed that most diurnal litter frogs are active foragers of hard-bodied prey such as ants; sit-and-wait predators of larger soft-bodied prey are curiously absent. Plots sampled under fruiting Ficus natalensis trees showed significantly higher prey densities, but litter amphibians and reptiles did not seem to respond to this increase. Of the physical and biotic factors measured in each plot, seasonal changes in soil moisture were most closely correlated with the patterns of herpetofauna abundance observed in the forest. This is consistent with the fact that Kibale receives less rain than any site where the ecology of the litter herpetofauna has been studied, and that most of the species present in Kibale are believed to have evolved in the wetter forests of eastern Congo-Zaire.

×

I compared species richness and habitat correlates of leaf-litter herpetofaunal abundance in undisturbed and selectively logged forests, and an abandoned pine plantation in Kibale National Park, Uganda. I sampled 50 randomly located 25 m2 litter plots in each area during the wet and dry seasons in 1997. Ten anuran, five lizard, and three snake species were captured in plots over the study. Assemblage composition was most similar at logged and unlogged sites. The logged forest herpetofauna had higher species richness and abundance than the unlogged forest, but diversity was greater in the unlogged forest due to greater evenness. In contrast, the pine plantation site had the highest richness, abundance, and evenness of the three study sites, but species composition was distinct from the other areas. Herpe- tofaunal densities were significantly lower in all three areas during the dry season than in the wet season. During the dry season, soil moisture, litter mass, topography, shrub cover, and number of fallen logs were significant positive predictors of herpetofaunal presence in litter plots, but only soil moisture was significant in the wet season. The interaction of moisture and topography appears to be important in determining seasonal patterns of litter herpetofaunal distribution. Comparison of litter herpetofaunal studies across the tropics have shown that mid-elevation faunas generally support fewer species than lowland faunas. Compared with other tropical mid-elevation litter faunas, Kibale supports an intermediate number of species, but at lower densities than observed at any other mid-elevation site reported in the literature.