The Herpetological Journal

pp. 69-76
Authors: Rock, Jennifer & Cree, Alison

Abstract: Nocturnal lizards inhabiting cool temperate environments potentially experience a wide range of body temperatures (T_b). We used radio telemetry to characterize field T_b in a nocturnal diplodactylid gecko (Hoplodactylus maculatus) from a high-latitude (45°S), sub-alpine site in southern New Zealand. Variation in T_b within days (diel), among days and among different reproductive groups of this viviparous species (pregnant females, non-pregnant females and males) was measured with temperature-sensitive transmitters. We found that surgical implantation of transmitters did not have a significant effect on selected temperature on a laboratory gradient (T_sel). Field T_b values were examined in concert with T_sel and microhabitat temperature in late summer, revealing marked fluctuations of up to 30 °C in T_b both within and between days. When weather conditions allowed, all reproductive groups exhibited some degree of thermoregulation, with T_b generally elevated at least 4 °C above microhabitat temperature and within the bounds (central 50%) of T_sel at the warmest times of day on most days. Considerable thermoregulation occurred early in the day, particularly for pregnant females, and is likely to have involved some degree of direct solar basking. Temperature telemetry revealed both extreme variability in T_b and complexity of thermoregulatory behaviour in a primarily nocturnal, thigmothermic lizard.

Keywords: MICROHABITAT TEMPERATURE, GECKO, THERMOREGULATION, REPRODUCTIVE CONDITION, DIPLODACTYLIDAE, TELEMETRY

pp. 77-82
Authors: Correa, Claudio; Lobos, Gabriel; Pastenes, Luis & Méndez, Marco A.

Abstract: Robinson Crusoe Island, located 670 km west of the coast of central Chile, is characterized by a high number of endemic and introduced species of plants and animals. This island lacks native amphibians or reptiles, but somewhat more than 30 years ago the toad Pleurodema thaul, native to continental Chile, was introduced. The coast of central Chile was identified as the geographic source of the introduced population of Robinson Crusoe by means of phylogenetic analyses of mitochondrial sequences. These analyses also suggest a high degree of phylogeographic structure for this species in continental Chile.

Keywords: JUAN FERNANDEZ ISLANDS, LEIUPERIDAE, INVASIVE SPECIES, PHYLOGEOGRAPHY, ANURAN

pp. 83-89
Authors: Davis, Andrew K. & Grayson, Kristine L.

Abstract: As aquatic adults, eastern red-spotted newts (Notophthalmus v. viridescens) are generally green with two rows of dorsal spots, which vary in number between individuals and range in colour from orange to red. The function of these spots is unknown, but it is possible that they serve as sexual ornamentations and we examined this hypothesis by testing for sexual dimorphism in spot characteristics. We used an image analysis approach that has been used previously with this and other amphibian species to compare the number, size and colour – redness (hue score) and brightness – of spots in 100 male and 100 female aquatic adult newts captured during the breeding season in Virginia. While we found no apparent sex-related differences in the numbers of spots, and only a minor difference in spot sizes, we discovered that adult male red-spotted newts had significantly redder and more brightly coloured dorsal spots than did females. We also found that spot brightness is positively associated with body size. As male red-spotted newts entice females to mate in part with a highly visual display (the #hula##dance#), the sexual dimorphism in spot colour we found could be associated with this display. Our results, taken together with current knowledge on the carotenoid pigments behind the red spot colour, suggest a role for spot coloration in the mating system of N. v. viridescens that should be examined further and considered in other studies of mate choice. In a more general sense, this discovery also leads us to question if this phenomenon is present in other amphibian species previously thought to be #monomorphic#

Keywords: IMAGE ANALYSIS, SPOT PATTERN, NOTOPHTHALMUS V. VIRIDESCENS, COLORATION, SEXUAL DIMORPHISM

pp. 91-96
Authors: Campos, Zilca; Magnusson, William; Sanaiotti, Tânia & Coutinho, Marcos

Abstract: Management strategies for crocodilians often include size-selective quotas designed to protect breeding females. However, little is known about among- and within-population variation in size and fecundity in crocodilians. Life-history theory predicts trade-offs between clutch size and egg size. Larger females usually have larger clutch sizes, and if they also produce larger eggs their contribution to reproductive effort may be greater than the number of eggs they produce. We studied the relationships among female size and clutch characteristics for an Amazonian population of Caiman crocodilus crocodilus between 2001 and 2007, and a Pantanal population of Caiman crocodilus yacare in 1996. Females in the Amazonian population were smaller, and showed significant differences from the Pantanal population for some relationships. Eggs lost weight during incubation in the Amazonian population but not in the Pantanal population. Despite these differences, the effect of egg size accounted for about one quarter of the total effect of female mass on clutch mass in both populations. Size-selective quotas should take into account that large females produce both more and larger eggs than do small females. However, size distributions of breeding females vary greatly among populations and legal size limits will be more effective if based on data from local populations.

Keywords: CAIMAN CROCODILUS, BREEDING FEMALES, REPRODUCTION, LIFE-HISTORY

pp. 97-102
Authors: Lu, Xin; Li, Bin; Li, Yang; Ma, Xiaoyan & Fellers, Gary M.

Abstract: Temperate anurans have energy substrates in the liver, fat bodies, carcass and gonads; these stores provide support for metabolism and egg production during hibernation, and for breeding activities in spring. This paper compares the energy budget shortly before hibernation among Rana chensinensis populations at elevations of 1400, 1700 and 2000 m along a river in northern China. The larger frogs, regardless of elevation, had relatively heavy storage organs and the masses of nearly all these organs were positively correlated with each other. After controlling for the effect of body size, we found no significant difference in energetic organ mass among different age classes for each of the three populations. There were sexual differences in energy strategy. Males in all populations accumulated greater reserves in liver, fat bodies and carcass than did females. In contrast, females put more energy into their ovaries and oviducts. Frogs from higher elevations tended to have heavier organs than those from lower elevations; however, the pattern did not vary systematically along fine environmental gradients. Mid-elevation R. chensinensis built up significantly more reserves than low-elevation individuals, but were similar to their highland conspecifics. Males from higher elevations tended to have heavier liver and fat bodies; females were similar in liver and ovary mass across all elevations, but formed heavier fat bodies, oviducts and somatic tissue at higher elevation sites.

Keywords: STORAGE ORGANS, LIFE HISTORY, SEX DIFFERENCES, ELEVATION

pp. 103-113
Authors: Gómez-Rodríguez, Carola; Bustamante, Javier; Koponen, Sampsa & Díaz-Paniagua, Carmen

Abstract: Remote sensing can provide an alternative to field data sampling in many species-habitat studies. However, its usefulness may depend on the species, habitat studied, spatial resolution and extent. We used a high spatial and spectral remotesensing image to locate and delineate small amphibian breeding sites in a Mediterranean ecosystem (Doñana National Park). We also evaluated its usefulness in detecting habitat heterogeneity (number and evenness of different radiometric zones) within ponds and its relationship to amphibian species richness. Furthermore, Generalized Linear Models (GLMs) were used to evaluate the usefulness of high-resolution remote-sensing data to model amphibian distribution at species level (presence/absence data), both when used alone or as a complement to field data. Amphibian species richness correlated positively with habitat heterogeneity when we discriminated a low number of potential different zones within ponds (four vs nine). For most species, remote-sensing data improved on amphibian distribution models built from field data but were of limited utility when used alone. In consequence, although remote-sensing data could be used for the preliminary identification of ponds supporting high species richness, we recommend initial assessment of its utility for identifying species-specific breeding sites before conducting survey programmes based on it.

Keywords: WETLANDS, MEDITERRANEAN TEMPORARY PONDS, HYPERSPECTRAL DATA, HABITAT HETEROGENEITY

pp. 115-118
Authors: Doherty-Bone, T.M.; Bielby, J.; Gonwouo, N.L.; LeBreton, M. & Cunningham, A.A.

Abstract: Establishing the presence in a region of the lethal amphibian pathogen Batrachochytrium dendrobatidis is important for predicting changes in amphibian assemblages, particularly in areas of high amphibian biodiversity. We examined 283 specimens of 26 anuran and one caecilian species inhabiting the highlands within North West Province, Cameroon, for the presence of B. dendrobatidis using real time PCR. All samples were negative for this pathogen. This part of Africa is a global hotspot for amphibian biodiversity. Our findings suggest that amphibians in this region are possibly naive to chytrid and are, therefore, at risk from the introduction of this pathogen.

Keywords: AFRICA, BATRACHOCHYTRIUM DENDROBATIDIS, BIAFRAN HIGHLANDS, AMPHIBIANS