Comparative analysis of the eye anatomy in fossorial and surface-living skink species (Reptilia: Scincidae), with special reference to the structure of the retina

We compared the eye anatomy of the scotopic fossorial Acontias orientalis, Acontias rieppeli and Typhlosaurus vermis with that of the photopic surface-living Trachylepis punctatissima, with particular reference to the retina. The findings were compared with published data on gecko species (Röll, 2001), to determine whether similar trends existed. The vestigial eye of T. vermis was not comparable with that of the other three skink species. The findings in A. orientalis, A. rieppeli and T. punctatissima were as follows: (a) A. rieppeli lacked a conus papillaris, (b) A. orientalis, A. rieppeli and T. punctatissima were pure-cone species but lacked a fovea, (c) estimated cone density in A. orientalis and A. rieppeli was lower than that in T. punctatissima, (d) the ellipsoid cone segment was smaller and the paraboloid segment larger in A. orientalis and A. rieppeli with the reverse in T. punctatissima, (e) VCL%, ONL%, OPL% and GCL% in A. orientalis and A. rieppeli were significantly greater than that of T. punctatissima, (f) INL% and IPL% in T. punctatissima was significantly greater, and (g) T. punctatissima had abundant Müller cells and fibres. Findings in the gecko species were congruent with those of the three skink species of the present study.     

Two newly recognized species of Hemidactylus (Squamata,Gekkonidae) from the Arabian Peninsula?and Sinai,Egypt

A recent molecular phylogeny of the Arid clade of the genus Hemidactylus revealed that the recently described H. saba and two unnamed Hemidactylus species from Sinai, Saudi Arabia and Yemen form a well-supported monophyletic group within the Arabian radiation of the genus. The name ‘Hemidactylus saba species group’ is suggested for this clade. According to the results of morphological comparisons and the molecular analyses using two mitochondrial (12S and cytb) and four nuclear (cmos, mc1r, rag1, rag2) genes, the name Hemidactylus granosus Heyden, 1827 is resurrected from the synonymy of H. turcicus for the Sinai and Saudi Arabian species. The third species of this group from Yemen is described formally as a new species H. ulii sp. n. The phylogenetic relationships of the members of ‘Hemidactylus saba species group’ are evaluated and the distribution and ecology of individual species are discussed.     

Multilocus phylogeography reveals nested endemism in a gecko across the monsoonal tropics of Australia

Multilocus phylogeography can uncover taxonomically unrecognized lineage diversity across complex biomes. The Australian monsoonal tropics include vast, ecologically intact savanna‐woodland plains interspersed with ancient sandstone uplands. Although recognized in general for its high species richness and endemism, the biodiversity of the region remains underexplored due to its remoteness. This is despite a high rate of ongoing species discovery, especially in wetter regions and for rock‐restricted taxa. To provide a baseline for ongoing comparative analyses, we tested for phylogeographic structure in an ecologically generalized and widespread taxon, the gecko Heteronotia binoei. We apply coalescent analyses to multilocus sequence data (mitochondrial DNA and eight nuclear DNA introns) from individuals sampled extensively and at fine scale across the region. The results demonstrate surprisingly deep and geographically nested lineage diversity. Several intra‐specific clades previously shown to be endemic to the region were themselves found to contain multiple, short‐range lineages. To infer landscapes with concentrations of unique phylogeographic diversity, we probabilistically estimate the ranges of lineages from point data and then, combining these estimates with the nDNA species tree, estimate phyloendemism across the region. Highest levels of phyloendemism occur in northern Top End, especially on islands, across the topographically complex Arnhem escarpment, and across the sandstone ranges of the western Gulf region. These results drive home that deep phylogeographic structure is prevalent in tropical low‐dispersal taxa, even ones that are ubiquitous across geography and habitats.     

A new species of Thecadactylus from Sint Maarten, Lesser Antilles (Reptilia, Squamata, Gekkonidae)

We describe a new species of Thecadactylusfrom the Caribbean island of Sint Maarten. The new species differs from all other species in the genus by having a distinct dorsal pattern of numerous irregular but sharply deliminated black spots and blotches on an otherwise almost patternless background.     

Natural colonization or introduction? Phylogeographical relationships and morphological differentiation of house geckos (Hemidactylus) from Madagascar

Several house gecko species of the genus Hemidactylus are almost cosmopolitan lizards, with distributions that have probably been shaped by natural transoceanic dispersal as well as by more recent human introductions. Here we revise the Hemidactylus populations of Madagascar and compare them genetically with populations from other sites in the Indian Ocean region. Morphological data strongly confirm the occurrence of three Hemidactylus species on Madagascar: Hemidactylus frenatus , distributed along the western coast of Madagascar; H. platycephalus , restricted to the north-west and the widespread H. mercatorius that occurs throughout the island, including coastal areas at sea level as well as big cities (Antananarivo, Fianarantsoa) at altitudes of 1200–1300 m above sea level. Analyses of partial sequences of the 16S rRNA gene in 46 Hemidactylus specimens from Madagascar, East Africa, South Asia, and the Comoro and Mascarene archipelagos demonstrated the presence of a fourth species, H. brooki, on the Mascarenes (Réunion, Rodrigues, and Mauritius) and Comoros (Moheli). The Malagasy populations of H. platycephalus were genetically uniform and differentiated from the African and Comoroan specimens studied. H. frenatus had a relatively low genetic differentiation over the whole region with no recognizable phylogeographical structure, indicating more recent colonizations or introductions. In contrast, H. mercatorius showed a strong phylogeographical structure of haplotypes, with two distinctly different lineages in Madagascar. Moreover, all Malagasy specimens differed strongly from the single African specimen included. This indicates that populations of H. mercatorius in Madagascar have a long history that predates human settlement.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 115–130.     

Divergent ecology of sympatric clones of the asexual gecko,Lepidodactylus lugubris

We report differences in the thermal biology, elevational, temporal and geographic distributions of sympatric clones of the widespread asexual house gecko, Lepidodactylus lugubris. The two most common L. lugubris clones in Fiji, clones 2NA and 2NB, differ significantly in preferred temperature as measured in a laboratory heat gradient, but were similar in critical thermal maximum and minimum. Significant differences were found in the relative frequency of clones 2NA, 2NB, and a third Fijian clone, clone 3NB, at seven sites along an elevational gradient in Fiji. Clone 2NB was not collected at sites above 235 m, consistent with its higher preferred temperature, whereas clone 2NA was captured as high as 835 m. Clone 3NB was extremely rare at sealevel (1% of all individuals at three sites below 100 m), but predominated at the two highest-elevation sites (42% and 100%). Clones 2NA and 2NB did not differ significantly in their activity time or ambient activity temperature at low-elevation sites. Clone 3NB however, was active on significantly cooler nights at two of those sites. These significant inter-clonal differences in spatial and temporal distribution should allow a more complete utilization of resources by the assemblage of clones than by any single clonal genotype, and may promote coexistence of clones at a within-island and within-site scale. Clone 2NA, which is the most common clone in Fiji and has the broadest elevational distribution, also has the widest geographic distribution. It was the predominant clone at 27 of 34 sites surveyed in nine Pacific archipelagoes. This suggests that the ecological attributes that favor this clone in Fiji also favor it elsewhere in the Pacific despite differing environmental conditions and clonal composition in those areas.     

Evidence for Gondwanan vicariance in an ancient clade of gecko lizards

Aim Geckos (Reptilia: Squamata), due to their great age and global distribution, are excellent candidates to test hypotheses of Gondwanan vicariance against post‐Gondwanan dispersal. Our aims are: to generate a phylogeny of the sphaerodactyl geckos and their closest relatives; evaluate previous phylogenetic hypotheses of the sphaerodactyl geckos with regard to the other major gecko lineages; and to use divergence date estimates to inform a biogeographical scenario regarding Gondwanan relationships and assess the roles of vicariance and dispersal in shaping the current distributions of the New World sphaerodactyl geckos and their closest Old World relatives. Location Africa, Asia, Europe, South America, Atlantic Ocean. Methods We used parsimony and partitioned Bayesian methods to analyse data from five nuclear genes to generate a phylogeny for the New World sphaerodactyl geckos and their close Old World relatives. We used dispersal–vicariance analysis to determine ancestral area relationships among clades, and divergence times were estimated from the phylogeny using nonparametric rate smoothing. Results We recovered a monophyletic group containing the New World sphaerodactyl genera, Coleodactylus, Gonatodes, Lepidoblepharis, Pseudogonatodes and Sphaerodactylus, and the Old World Gekkotan genera Aristelliger, Euleptes, Quedenfeldtia, Pristurus, Saurodactylus and Teratoscincus. The dispersal–vicariance analysis indicated that the ancestral area for this clade was North Africa and surrounding regions. The divergence between the New World spaherodactyl geckos and their closest Old World relative was estimated to have occurred c. 96 Myr bp . Main conclusions Here we provide the first molecular genetic phylogenetic hypothesis of the New World sphaerodactyl geckos and their closest Old World relatives. A combination of divergence date estimates and dispersal–vicariance analysis informed a biogeographical scenario indicating that the split between the sphaerodactyl geckos and their African relatives coincided with the Africa/South America split and the opening of the Atlantic Ocean. We resurrect the family name Sphaerodactylidae to represent the expanded sphaerodactyl clade.     

Habitat-dependent thermal regimes of two hawaiian geckos (Reptilla: gekkonidae)

1. 1.Effects of habitat on the thermal regime were investigated in two diurno—nocturnal geckos in Hawaii.

2. 2.In trees Hemidactylus frenatus thermoregulated in daytime with body temperature (BT) above air temperture (AT); in houses some thermoregulated likewise in daytime but mainly the species thermoregulated at night, on electric lamps, to the same BT as in trees by day.

3. 3.Lepidodactylus lugubris in trees thermoregulated in daytime, its BT lower than in H. frenatus. In the rocks it had at night a BT resembling that in trees in daytime, because the thermal cycle in rock crevices lagged behind outside AT.

4. 4.The flexibility of these geckos in thermal regime and activity cycle preadapts them to both migration and invasion of houses.

沙虎属Teratoscincus系统学研究进展

沙虎属是壁虎科中比较特化的沙生蜥蜴类,主要分布在中亚及其临近地区的低海拔荒漠中,本文结合文献资料和实物标本,对沙虎属的形态分类概况、染色体研究及分子生物学进行进行了初步总结;并在此基础上,提出了沙虎属尚待研究的问题。     

Generalization of predator recognition: Velvet geckos display anti-predator behaviours in response to chemicals from non-dangerous elapid snakes

Many prey species detect chemical cues from predators and modify their behaviours in ways that reduce their risk of predation. Theory predicts that prey should modify their anti-predator responses according to the degree of threat posed by the predator. That is, prey should show the strongest responses to chemicals of highly dangerous prey, but should ignore or respond weakly to chemicals from non-dangerous predators. However, if anti-predator behaviours are not costly, and predators are rarely encountered, prey may exhibit generalised antipredator behaviours to dangerous and non-dangerous predators. In Australia, most elapid snakes eat lizards, and are therefore potentially dangerous to lizard prey. Recently, we found that the nocturnal velvet gecko Oedura lesueurii responds to chemicals from dangerous and non-dangerous elapid snakes, suggesting that it displays gen-eralised anti-predator behaviours to chemicals from elapid snakes. To explore the generality of this result, we videotaped the be-haviour of velvet geckos in the presence of chemical cues from two small elapid snakes that rarely consume geckos: the nocturnal golden-crowned snake Cacophis squamulosus and the diurnal marsh snake Hemiaspis signata. We also videotaped geckos in tri-als involving unsceted cards (controls) and cologne-scented cards (pungency controls). In trials involving Cacophis and Hemi-aspis chemicals, 50% and 63% of geckos spent long time periods (> 3 min) freezing whilst pressed flat against the substrate, re-spectively. Over half the geckos tested exhibited anti-predator behaviours (tail waving, tail vibration, running) in response to Ca-cophis (67%) or Hemiaspis (63%) chemicals. These behaviours were not observed in control or pungency control trials. Our re-sults support the idea that the velvet gecko displays generalised anti-predator responses to chemical cues from elapid snakes. Generalised responses to predator chemicals may be common in prey species that co-occur with multiple, ecologically similar, dangerous predators.