The Herpetological Journal

pp. 111-118
Authors: Harvey, Daniel S. & Platenberg, Renata J.

Abstract: Wildlife managers must often make conservation decisions based on uncertain and incomplete information. The challenge is to make the most robust predictions of species' requirements given these limitations. This is particularly the case when the species is rare and difficult to locate and baseline data are virtually non-existent. In the absence of other data, we used 143 opportunistic observations collected over 25 years and geographical information systems to predict the habitat of the endangered Virgin Islands tree boa (Epicrates granti) on St Thomas, United States Virgin Islands. We compared the habitat characteristics surrounding observations to the rest of the island using logistic habitat models with varying spatial resolution. Models formed with smaller-scale presence definitions were better able to discriminate areas of occurrence from the rest of the island but were more biased towards developed areas. To investigate habitat associations below the resolution of the models, we compared microhabitat near high-certainty observations with microhabitat at nearby, random locations. Snakes were disproportionately found in low elevation (<150 m) areas with non-stony soils. Vegetation near snakes consisted of woody plants 5–10 m tall with a high degree of vegetation continuity (e.g. mangroves, drought deciduous forests, thicket/scrub). This habitat occurs primarily along the southeastern coast of St Thomas. Our multi-scale approach allowed a more informed prediction of the snakes' requirements than any single-scale approach, particularly in light of the variable resolution of the observations.

Keywords: HABITAT MODELLING, ST THOMAS, BIOLOGICAL CONSERVATION, UNITED STATES VIRGIN ISLANDS

pp. 119-126
Authors: de C. Kokubum, Marcelo N.; Maciel, Natan M.; Matsushita, Rubens H.; de Queiróz-Júnior, Armando T. & Sebben, Antonio

Abstract: This study reports on previously unknown characteristics of the reproductive biology of Leptodactylus troglodytes, including reproductive site, courtship and territorial behaviour, advertisement, territorial, courtship and reciprocation calls, fecundity and architecture of underground chambers. The ability of tadpoles to produce foam was also tested in the laboratory. Individuals of L. troglodytes bred near temporary ponds in shaded areas and eggs were laid in underground chambers. Three courtship behaviour sequences were recorded. Courtship and reciprocation calls are important during courtship to maintain association between the bonding pair. Reciprocation calls emitted by females may indicate gender avoiding attacks by males. The underground chambers examined had a complex architecture consisting of multiple internal spherical rooms. Foam nests with eggs/larvae in different stages of development were found inside the chambers. Tadpoles of Leptodactylus troglodytes were able to regenerate foam nests within three hours after the beginning of the experiment. This behaviour was also found in other species of the L. fuscus, L. pentadactylus and L. marmoratus species groups.

Keywords: VOCALIZATION, ARCHITECTURE OF UNDERGROUND CHAMBERS, REPRODUCTIVE SITE, TADPOLES, BEHAVIOUR, FECUNDITY

pp. 127-133
Authors: Wu, Qiong; Parker, Scott L. & Thompson, Michael B.

Abstract: Fossorial and nocturnal lizards have limited opportunities to thermoregulate because they do not have access to basking opportunities, which has implications for their thermal physiology and metabolism. We measured substrate temperatures (T_s) in the field, and selected body temperatures (T_b) and metabolic rates in the laboratory, in fossorial skinks, Saiphos equalis, to quantify basic aspects of their thermal and metabolic physiology. Saiphos equalis selects relatively cool temperatures over a broad range (approximately 17–24 °C), suggesting that it does not thermoregulate precisely. Individuals of S. equalis are active more often at night than during the day. Rate of oxygen consumption was measured at 2 °C intervals from 10–30 °C in adult lizards. Metabolic rate increased as a function of temperature but there was no significant difference in VO₂ over the preferred temperature range. Like many other fossorial lizards, S. equalis is nocturnal and selects relatively low body temperatures compared to heliothermic lizard species.

Keywords: THERMOREGULATION, NOCTURNAL LIZARD, OXYGEN CONSUMPTION, METABOLISM

pp. 135-142
Authors: Meek, Roger

Abstract: Road mortalities of two lizard and four snake species were recorded in the Vendée region of western France over a period of four years. Road-kills were more frequent in the foraging snakes Hierophis (= Coluber) viridiflavus and Natrix natrix as well as the lizard Lacerta bilineata, and lower in the small lizard Podarcis muralis and the sedentary snakes Vipera aspis and Natrix maura. Road-kills were found throughout the active year, with differences in size class and monthly frequencies in H. viridiflavus, N. natrix and L. bilineata commencing in June. Pearson rank correlation coefficients revealed a significant positive association between monthly road-kill and monthly live counts of H. viridiflavus and N. natrix, suggesting regular road crossings in these species. Road traffic volume was related to the number of road deaths using regression analysis of the log-transformed data. This gave an allometric equation with an exponent of 0.75, which was not significantly different from 1, the exponent required if road-kills increase in direct proportion to increasing road traffic volume. The highest traffic volume route showed lower than expected mortalities, but fewer numbers of species living in the vicinity. Models of road-kill vulnerability in H. viridiflavus and N. natrix, derived from the integration of size frequencies of road-kill and live distributions, predict high vulnerability in small and large individuals. In lizards, particularly L. bilineata, road basking is probably the main factor determining mortality, in addition to species velocities, traffic volumes, road widths, abundance at the sides of roads, and behaviour and activity patterns.

Keywords: LIZARDS, SNAKES, TRAFFIC VOLUMES, BEHAVIOUR

pp. 143-149
Authors: Sahoo, Gunanidhi; Mohapatra, Birendra K. & Dutta, Sushil K.

Abstract: We examined the chemical composition and ultrastructure of the eggshells of olive ridley turtles, Lepidochelys olivacea , at various stages of embryonic development (freshly laid, 42 days developed and hatched). The eggshell is mainly composed of calcium carbonate present in its aragonite morph, and serves as a source of calcium for the developing embryo. Gradual utilization of eggshell calcium by the developing embryo was reflected by sequential reduction of calcium content from the fresh eggshell (191±32 mg), through 42 days into development (151±36 mg), to hatching (69±11 mg). Structurally, the shells of olive ridley turtle eggs were composed of an outer inorganic calcareous layer, an inner organic fibrous layer and a thin boundary layer that enclosed the egg contents. Calcium resorption by the developing embryo also brought about remarkable modifications in the structure of the eggshell. Fresh eggshells were composed of closely spaced, organized nodular shell units, disoriented spicules and a dense mat of membrane fibres. After 42 days of incubation, these nodules changed to polygonal units with large inter-spaces and loose fibrilliar membranes, whereas the hatched eggshell appeared amorphous and homogenous with disoriented membrane fibres. A 37% decrease in shell thickness (150±11 m in fresh to about 100±6 m in hatched) was observed between laying and hatching. This decrease in shell thickness and structural modifications, with respect to compositional changes, were the effect of calcium resorption from the eggshell by the embryo during its development.

Keywords: SHELL UNITS, LEPIDOCHELYS OLIVACEA, MEMBRANE LAYER, ARAGONITE, CALCIUM

pp. 151-162
Authors: Guo, Peng; Malhotra, Anita; Thorpe, Roger S.; Creer, Simon & Pook, Catharine E.

Abstract: Although the genus Viridovipera has been relatively well studied recently, the status and diagnosis of V. yunnanensis are still unclear. In this study, two samples collected from southwestern Sichuan (Huili), which are putative V. yunnanensis, were analysed in a molecular phylogeny for the first time. These two samples formed a well supported clade that was distinct from its congeners. Multivariate morphometric analysis (principal components analysis and canonical variate analysis) including these and 14 other new Chinese specimens showed that male specimens from Tengchong, Nujiang (Yunnan), and northern Burma are very similar to both the holotype and paratypes of V. yunnanensis in external morphology, and are morphologically distinct from their congeners. A similar trend was found in two new female specimens from Huili, Sichuan. Other new Chinese specimens can usually be allocated to either V. stejnegeri or V. gumprechti, but specimens from northeastern India remain ambiguous in their affinities. Several specimens were inconsistently allocated to species in the phylogenetic and the morphometric analysis; this may be a signal of introgression of mtDNA across species boundaries following hybridization between species. We conclude that although V. yunnanensis represents a valid taxon, which in parts of its range is sympatric with both V. gumprechti and V. stejnegeri, the exact morphological and geographical limits of this species are still not clear. Hemipenial characteristics show only subtle and inconsistent differences between species within Viridovipera and may not be a useful diagnostic character at the species level. We provide a redescription of the holotype of V. yunnanensis and a comparison with similar congeneric species, as a starting point for further investigations of hybridization among them, which ideally should be based on new collections in Sichuan and Yunnan provinces of China, the northeastern region of India and northern Burma, where at least two Viridovipera species seem to co-exist.

Keywords: PHYLOGENETICS, MORPHOMETRICS, NORTHEASTERN INDIA, PITVIPERS, HEMIPENIS, VIRIDOVIPERA YUNNANENSIS