Using multilocus approach to uncover cryptic diversity within Pseudotrapelus lizards from Saudi Arabia

The agamid Pseudotrapelus lizards inhabit the mountainous areas of the Arabian Peninsula and eastern North Africa. Currently six Pseudotrapelus species are recognised, though diagnostic morphological characters are still lacking, creating great difficulty in describing new species. Recently, two specimens of Pseudotrapelus were collected from the vicinity of Riyadh in central Saudi Arabia, an area that was not sampled in previous phylogenetic studies. In here we used both mitochondrial and nuclear data to investigate the phylogenetic position of the new samples, and assess their phylogenetic relationships with the other recognised species of Pseudotrapelus from across the distribution range of the genus. We used a multilocus approach of haplotype networks, concatenated datasets and species trees, performed mitochondrial and nuclear species delimitation analyses, and estimated divergence times. In general, our results support previous molecular studies and uncover the presence of cryptic diversity within Pseudotrapelus. The phylogenetic structure of the genus is of two major clades and within them seven distinct, delimited phylogenetic groups belonging to the six recognised species and the seventh to the individuals from Riyadh. The Riyadh specimens were distinct in all analyses performed. We suggest that the new specimens from the Riyadh area are a distinct lineage, forming a clade with their phylogenetic relatives, P. sinaitus and P. chlodnickii. The clade formed by these three species diverged during the Late Miocene around 6.4 Ma, with cladogenesis possibly facilitated by vicariance and isolation caused due to climatic fluctuations and the progression of sandy areas. Our results suggest further morphological research is necessary to revise the taxonomic status of this lineage and of the entire genus.     

Evaluation of Enrichment for Reptiles in Zoos

Studies on environmental enrichment for reptiles are lacking in the scientific literature. Although the literature reflects a limited take on reptile enrichment in the zoological community, it may not be the case in reality as enrichment is generally considered an important aspect of the care of nonhuman animals in captivity. This project investigated the current state of reptile enrichment as it is being used in zoos. Although respondents were disproportionately accredited by the Association of Zoos and Aquariums, the results showed many forms of enrichment being used for reptiles in zoos and happening at much greater levels than what has been suggested in the scientific literature. There were significant differences between a) reptile groups for each form of enrichment, and b) enrichment forms within each reptile group, except with the use of natural enrichment devices and structural/habitat design, which did not differ across all reptile groups. Enrichment goals, assessment methods, and sources of information for reptile enrichment used by zoos suggest the need for more scientific publications for facilities to make evidence-based decisions to improve the welfare of reptiles in captivity.     

Relative influence of habitat heterogeneity, climate, human disturbance, and spatial structure on vertebrate species richness in Spain

Many factors affect the distribution of species richness. This study examines the relative influence of habitat heterogeneity, climate, human disturbance, and spatial structure on the species-richness distribution of terrestrial vertebrates (amphibians, reptiles, birds and mammals) in mainland Spain. The results indicate that spatial structure and environment exert similar influences on species richness. For all four taxa, species richness increases southward and northward, being lower in the center of the country, when controlled for other variables. This may be the result of a peninsular effect, as found in other studies, and reflect the importance of historical events on species richness in the Iberian Peninsula. Climate is more important than habitat heterogeneity in determining species richness. Temperature is positively correlated with amphibian, reptile, and bird species richness, while mammalian species richness is highest at intermediate temperatures. This effect is stronger in ectotherms than among endotherms, perhaps reflecting physiological differences. Precipitation positively correlates with bird and mammalian species richness, but has no effect on ectotherm species richness. Amphibian species richness increases with altitudinal range, and bird species richness with habitat diversity. Human population density is positively correlated with bird and mammalian species richness, but does not affect ectotherm species richness, while amphibian and bird species richness is highest at moderate levels of human land alteration (farmland). However, unexplained variance remains, and we discuss that the effects of environmental variables on species richness may vary geographically, causing different effects to be obscured on a national scale, diminishing the explanatory power of environmental variables.     

Fungus gardens of the leafcutter ant Atta colombica function as egg nurseries for the snake Leptodeira annulata

Attine ants are well known for their mutualistic symbiosis with fungus gardens, but many other symbionts and commensals have been described. Here, we report the discovery of two clusters of large snake eggs in neighboring fungus gardens of a mature Atta colombica colony. The eggs were completely embedded within the fungus garden and were ignored by the host ants, even when we placed them into another, freshly excavated fungus garden of the same colony. All five eggs contained embryos and two snakes eventually hatched, which we identified as being banded cat eyed snakes Leptodeira annulata L. Ant fungus gardens are likely to provide ideal climatic conditions for developing snake eggs and almost complete protection from egg predation. Our observations therefore indicate that mature banded cat eyed snakes are able to enter and oviposit in large and well defended Atta colonies without being attacked by ant soldiers and that also newly hatched snakes manage to avoid ant attacks when they leaving their host colony. We speculate that L. annulata might use Atta and Acromyrmex leafcutter ant colonies as egg nurseries by some form of chemical insignificance, but more work is needed to understand the details of this interaction. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Identification of diverse molecular forms of GnRH in reptile brain

Gonadotropin-releasing hormone (GnRH) molecular forms in the brains of three reptiles, Alligator mississippiensis (alligator), Calcides ocellatus tiligugu (skink) and Podarcis s. sicula (lizard) were characterized by high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera, and by assessment of luteinizing (LH)-releasing activity in chicken dispersed pituitary cells. In alligator brain two GnRHs had identical properties to the two known forms of chicken hypothalamic GnRH (Gln⁸-GnRH and His⁵,Trp⁷,Tyr⁸-GnRH) in their elution on two reverse phase HPLC systems, cross-reaction with region-specific GnRH antisera, and ability to release LH. In skink brain, one immunoreactive and bioactive GnRH form, which eluted in the same position as His⁵,Trp⁷,Tyr⁸-GnRH on reverse phase HPLC, was identified. Three bioactive and immunoreactive GnRHs were detected in lizard brain. One form had similar properties to salmon brain GnRH (Trp⁷,Leu⁸-GnRH). The other two GnRH-like peptides are novel forms. One of these forms eluted in the same position as Gln⁸-GnRH on HPLC but had different immunological properties, while the third form was a rather hydrophobic species which appeared to be modified in the middle region of the molecule.     

Environmental Correlates for Species Richness among Amphibians and Reptiles in a Climate Transition Area

Correlations between environmental factors and the distribution of amphibian and reptile species richness were investigated in a climate transition area, Peneda-Gerês National Park (PNPG), in North-Western Portugal. Using presence-data at a local-scale (1 × 1 km), Ecological-Niche Factor Analysis (ENFA) identified a mixture of climatic (precipitation and number of days with fog), topographical (altitude and relief) and habitat factors (number of watercourses and water surfaces, the type of the largest water surface and tree diversity cover), as accurate predictors of species occurrence. Three factors were common for both taxonomic groups, and consistently presented a positive relation with species occurrence: precipitation, number of water surfaces, and tree diversity cover; suggesting a strong coincidence in the environmental correlates that influence amphibian and reptile species richness. Distribution patterns of observed and predicted species richness were compared using a Geographical Information System. Overall, three high species richness areas were predicted in common for both taxonomic groups and two additional areas for amphibians only. These areas matched with the observed species richness but suggested larger areas of high species richness. The location of the PNPG in a biogeographic crossroad, between Euro-Siberian and Mediterranean provinces, emphasised species richness of amphibians and reptiles and suggests a high priority conservation status for this protected area. Most of Central-Northern Portugal is located in a climatic transition area; therefore, increased species richness should be expected for other areas. Local scale studies for other protected areas should be planned as a framework for the development of multi-scale conservation planning by Portuguese authorities.     

Ultrastructure of the sexual segments of the kidney in male and female lizards,Cnemidophorus l. lemniscatus (L.)

Summary Kidneys of adult male and female lizards were studied by electron microscopy, in order to understand the ultrastructure of the collecting duct and a differentiated part thereof, the sexual segment, which is an important accessory sexual organ. First portion of sexual segment in males: The cells are filled with large secretory granules of a wide range of opacities. The granular endoplasmic reticulum is abundant; basal formations of superimposed flat cisternae are frequent. Distended vesicles and microvesicles prevail in the supranuclear, well developed Golgi apparatus. Evidences indicate that secretion of these cells is holocrine. Second portion of sexual segment in males: All of the secretory granules are apical in location and relatively electron-opaque; they show a denser core. This core is formed by a substance which, after lying in contact with ribosomes, enters the secretory vesicles of the highly developed Golgi apparatus. A lighter substance is then condensed around it. The secretion of the granules is merocrine. The granular endoplasmic reticulum is very abundant in these cells, but basal ergastoplasmic formations are lacking. Sexual segment in females: The cells show features similar to those of the male first portion, but they are smaller. Undifferentiated collecting duct: Most of the cells are mucigenic. They have small ovoid, apical secretory granules. The density of the granules varies from cell to cell; when they are electron-lucent, they exhibit laminar or dotted opaque figures. Moderately developed Golgi apparatus and granular endoplasmic reticulum, as well as elongated mitochondria, occur in mucigenic cells. Intercalated among the latter are non-secretory cells. They have very abundant mitochondria, numerous microvilli, many pinocytic and smooth-membrane vesicles, whereas the organelles participating in synthetic processes are poorly developed; their function is most likely related to active solute transport.     

Effects of metopirone on the structure of endocrine glands in the male lizard,Cnemidophorus l. lemniscatus (L.)

Summary Adrenals, pituitary glands, thyroids, testes and kidneys of metopirone-treated and control male lizards were studied by light microscopy. Pituitary-interrenal axis: A great hypertrophy and hyperplasia of the interrenal cells and the pituitary corticotrophs were found in the experimental group. Pituitary-thyroid axis: Metopirone-treated animals showed a moderate hypertrophy and degranulation of pituitary thyrotrophs, and signs of uneven hyperactivity of the thyroid. Pituitary-testicular axis: By effect of metopirone, a marked regression of pituitary interstitiotrophs and a virtual disappearance of the testicular interstitial gland took place. The second portion of the kidney sexual segments appeared degranulated as in castrated animals. The pituitary folliculotrophs and the seminiferous epithelium of the testis did not show alterations.     

High Evolutionary Rates in Nuclear Genes of Squamates

We compared nonsynonymous substitution rates (Ka) of nuclear coding genes between four major groups of living sauropsids (reptiles): birds, squamates, crocodiles, and turtles. Since only 9 orthologous genes are known in all the four taxonomic groups, we searched for orthologous genes known in chicken and at least one of any representative of poikilotherm sauropsids. Thus, we analyzed three additional data sets: 28 genes identified in chicken and various squamates, 24 genes identified in chicken and crocodilians, and 20 genes identified in chicken and turtles. To compare nonsynonymous substitution rates between all lineages of sauropsids, we used the relative-rate test with human genes as the outgroup. We show that 22/28 nuclear coding genes of squamates, especially snakes (15/16), have an higher evolutionary rate than those in chicken (in mean, 30–40% faster). However, no such difference is detected between crocodiles, turtles and chicken. Higher substitution rate in squamates nuclear coding genes than in chicken, and probably than in other sauropsids, could explain some of the difficulties in resolving the molecular phylogeny of reptiles. Received: 5 July 2000 / Accepted: 13 February 2001     

两栖爬行动物的分子系统发生

介绍了两栖爬行动物分子系统发生研究中选用的分子信息的种类及已发表的蛙类,蟾蜍类,龟类,蜥蜴类和蛇类等的分子系统学研究,这些研究中使用的DNA信息主要为mtDNA序列,也使用了一些核DNA序列。其研究的内容涉及目间,科间等高级阶元的系统发生关系,以及属间,种间以及亚种或种群间的系统发生关系。