The Herpetological Journal

pp. 337-346
Authors: Jowers, M. J.; Campell-Palmer, R.; Walsh, P. T. & Downie, J. R.

Abstract: The stream frog, Mannophryne trinitatis, lives in and beside steep mountain streams of Trinidad's Northern and Central ranges. Male frogs have strong anti-predator behaviour and prefer to deposit tadpoles in pools that lack predators (particularly the fish Rivulus hartii and the freshwater prawn Macrobrachium carcinus). The two predators are rarely found in the same streams and different M. trinitatis populations may show specific anti-predator behaviour to the predators they encounter in the wild. To assess tadpole spatial avoidance of predators, we presented small and larger tadpoles from four M. trinitatis populations to each predator. Three tadpole sources were from the Northern Range: Mount Saint Benedict, Lopinot (where R. hartii is abundant), and the Maracas Bay area (where M. carcinus is present); the fourth was from Tamana cave, Central Range, where neither predator occurs. To determine predator detection mechanisms employed by the tadpoles, we presented the predators in three container types: a mesh cage (for chemical and visual detection), an opaque container with holes (chemical but no visual detection), and a transparent container (visual but no chemical detection). Different sized tadpoles (large and small) showed the same response to predators, and tadpoles principally used chemical cues to detect predators. All populations showed a stronger response to the presence of R. hartii than to M. carcinus. We attribute this latter difference to the restricted distribution of M. carcinus and to the few sympatric zones between the tadpoles and these predators. Thus tadpoles lacked a specific anti-predator response to M. carcinus. Naïve tadpoles from Mount Saint Benedict and Tamana that had never previously encountered either of the predators showed strong anti-predator responses, suggesting that the anti-predator response is likely to be inherited.

Keywords: TRINIDAD, MACROBRACHIUM, RIVULUS, ANTI-PREDATOR BEHAVIOUR

pp. 347-352
Authors: Gustafson, Daniel H.; Pettersson, Cecilia Journath & Malmgren, Jan C.

Abstract: In a field study in south central Sweden, we analysed the diversity of macrophytes in paired samples of ponds in a total of five geographically separated sites. Each pair of ponds involved one pond with presence of great crested newts (Triturus cristatus) and one pond in which newts were absent. Ponds with presence of great crested newts had a significantly higher mean number of plant species than ponds without newts. Newts occurred in ponds that tended to have a lower amount of pond area covered by surface vegetation, although this difference was not statistically significant. Macrophyte diversity also tended to increase more steeply in ponds with T. cristatus, compared with ponds without newts. Broad-leaved pond weed (Potamogeton natans) and square-leaved liverwort (Chiloscyphus pallescens) were among the plants that were most associated with presence of great crested newts. Plant diversity had a slightly more nested structure for ponds with great crested newts than for those without, which indicates a more homogeneous plant species assemblage in the former group of ponds. Overall, the results indicate that the great crested newt may be a reliable and useful indicator species for high plant species richness in ponds and small wetlands, which may be valuable for environmental monitoring and conservation in pond landscapes.

Keywords: HABITAT SELECTION, POND SUCCESSION, AMPHIBIA, SPECIES DISTRIBUTION PATTERNS

pp. 353-362
Authors: Pizzatto, Lígia & Marques, Otavio A. V.

Abstract: This study reports on aspects of reproduction in the water snake Liophis miliaris from four regions in Brazil: (1) northern coastal Atlantic forest, (2) southern coastal Atlantic forest, (3) northern inland Atlantic forest; and (4) southern inland Atlantic forest. In the northern coastal Atlantic forest, where there is little climate variation, the reproductive cycle of this species is continuous, with vitellogenesis and oviposition occurring throughout the year. Newly hatched snakes are found mainly in January. In other regions the cycle is seasonal and related to warmer and rainy periods, with vitellogenesis and oviposition occurring mainly from September to February. Hatchlings are more abundant from February to April, at the end of the rainy season. In the northern Atlantic forest newly hatched snakes have smaller body sizes than in the other regions. Sperm production seems to occur throughout the year in all regions, and where reproduction is seasonal, mating seems to be disassociated from vitellogenesis, suggesting that sperm may be stored by females over the winter. Females with oviductal eggs did not feed, whereas those ones with secondary vitellogenic follicles fed more frequently than non-reproductive females. In all regions, the activity pattern of adult Liophis miliaris seems to be related to reproductive cycles and climate variation.

Keywords: SERPENTES, GEOGRAPHIC VARIATION, SEASONAL ACTIVITY, REPRODUCTION

pp. 363-369
Authors: Snell, Charles & Evans, I. H.

Abstract: A method has been developed for discriminating between the common frog (Rana temporaria) and the moor frog (Rana arvalis) using either of two primers in RAPD analysis of DNA samples extracted from larval tail tips. These two frog species can be extremely difficult to distinguish morphologically at the egg clump and larval stages, which are very convenient stages for monitoring populations when there are conservation concerns. The adults need capture and detailed morphological examination to effect certain identification, this being particularly true for edge-of-range populations. The two primers also distinguished DNA samples of common toad (Bufo bufo), natterjack toad (Bufo calamita), pool frog (Rana lessonae) and the marsh frog (Rana ridibunda). Additionally, findings are reported for a third primer which distinguished, intraspecifically, between relatively closely located common frog (Rana temporaria) populations in southern England.

Keywords: FROG IDENTIFICATION, ANURA, POPULATION ASSESSMENT, MOLECULAR GENETICS

pp. 371-376
Authors: Almeida-Santos, Selma M.; Pizzatto, Lígia & Marques, Otavio A. V.

Abstract: Dissection of preserved Atlantic coral snakes Micrurus corallinus, plus field data and histological analysis, provided information on male reproductive cycles. Testes are larger during autumn, when sperm production occurs, and smaller in spring, when spermatogenesis stops. The diameter of the distal deferent ducts is small in summer–autumn, when sperm are hardly found in the lumen, and it increases in winter–spring, when sperm is abundant, just prior to the mating season. Thus, the male cycle of M. corallinus is post-nuptial, whereas the female cycle is prenuptial. Although gametogenesis is not simultaneous in both sexes, the coordination of their cycles is guaranteed by sperm storage by males. Our data indicate that the diameter of the deferent duct is a good indication of the mating season, mainly when reproductive cycles are post-nuptial. Mate searching and aggregation occurs in the spring, and activity in both sexes may be highly related to their reproductive cycles.

Keywords: SNAKE, AGGREGATION, SPERMATOGENIC CYCLE, REPRODUCTION, SPERM STORAGE

pp. 377-385
Authors: Roberts, J. L. and Brown, J. L. and von May, R. and Arizabal, W. and Presar, A. and Symula, R. and Schulte, R. and Summers, k.

Abstract: Despite many taxonomic revisions, systematic relationships among members of the genus Dendrobates remain poorly understood, particularly the connections between taxa in Amazonia and those in northern South America and Central America. We combine new mitochondrial sequence data with data from previous analyses in order to investigate the relationships among Dendrobates from each major biogeographic region. We address the phylogenetic position of taxa not included in previous molecular systematic analyses, including Dendrobates flavovittatus, D. duellmani, D. galactonotus, D. mysteriosus, and a new Dendrobates species from Brazil. We attempt to resolve relationships among former members of the genus Minyobates, and we consider the biogeographic and behavioural implications of the overall tree topology.

Keywords: MINYOBATES, SYSTEMATICS, NEOTROPICS, AMAZONIA

pp. 387-394
Authors: Schaefer, Eduardo F.; Hamann, Monika I.; Kehr, Arturo I.; González, Cynthya E. & Duré, Marta I.

Abstract: We studied the trophic and reproductive ecology and document the helminth fauna of the Cei's white-lipped frog, Leptodactylus chaquensis, from north-eastern Argentina. This frog is a generalist predator, using an intermediate strategy between active foraging and sit and wait predation. The diet consisted of 17 types of prey and was dominated numerically and volumetrically by coleopterans. The number of mature ova per female (ovarian complement) ranged from 3113 to 16234, and the ovum diameter varied from 0.4 to 1.2 mm. The testes mass ranged from 0.32 to 1.54 g, and the species has an explosive reproductive pattern. The parasite fauna was rich, consisting of 20 species of helminths (twelve trematodes, one cestodes, six nematodes and one acanthocephalan), the kidneys, lungs and large intestine being the organs most infected. The trophic niche breadth and the habitats where this species is living structured the parasite community.

Keywords: REPRODUCTION, DIET, FROG, HELMINTHS, PARASITES

pp. 395-402
Authors: Lampo, Margarita; Rodríguez-contreras, Argelia; La Marca, Enrique & Daszak, Peter

Abstract: Chytridiomycosis has been identified as one of the major forces driving global amphibian declines. Between 1988 and 1994, five Atelopus species endemic to the Venezuelan Andes disappeared. We examined histological samples of Andean Atelopus species available in Venezuelan museum collections for the presence of the chytrid fungus Batrachochytrium dendrobatidis. When infection was detected, sympatric species were examined to investigate the occurrence of the pathogen and how widespread it was. Infection with B. dendrobatidis is reported for the first time in Atelopus carbonerensis, A. mucubajiensis and A. sorianoi, Mannophryne cordilleriana and an undescribed Leptodactylus species. The spatio-temporal patterns of prevalence of this pathogen in Atelopus individuals, with all infections concentrated in one year but spread over distant locations, suggest that synchronized epidemic outbreaks occurred in populations of these Atelopus species in the years prior to their disappearances. Local climate data indicate that one of the most severe dry seasons recorded in the region since 1970 coincided with these epidemic events. The climatic-linked epidemic hypothesis seems a plausible explanation for the coincidence between the observed amphibian declines, the chytridiomycosis outbreaks and the droughts recorded in that area.

Keywords: CLIMATE CHANGE, BATRACHOCHYTRIUM DENDROBATIDIS, AMPHIBIAN DECLINES, EMERGING DISEASES

pp. 403-405
Authors: Avila, Robson W.; Ferreira, Vanda L. & Souza, Vanessa B.

Abstract: The biology of blindsnakes is virtually unknown. Herein, we present data on the biology of the blindsnake Typhlops brongersmianus from a semideciduous forest in Central Brazil. Males had longer tails and matured at smaller sizes than did conspecific females. Reproduction was highly seasonal, with clutch size of 4-5 eggs and oviposition in the early wet season. T. brongersmianus fed mainly on the pupae and larvae of ants, with ingestion of large number of prey items. Our findings agree with other studies of diet and reproduction of scolecophidians from other parts of the world.

Keywords: NEOTROPICS, DIET, SNAKE, REPRODUCTION