The Herpetological Journal

pp. 175-186
Authors: Passos, Paulo; Lynch, John D. & Fernandes, Ronaldo

Abstract: The taxonomic status of Atractus sanctaemartae and A. nebularis is revised on the basis of quantitative and qualitative analyses of morphological characters (meristics, morphometrics, colour pattern and hemipenis). Characters used previously for diagnosing Atractus nebularis from A. sanctaemartae are demystified, and the synonymy of these species is proposed. Colour pattern, meristic, morphometrical and scale ornamentation differences originally employed in recognizing both taxa are explained as sexually dimorphic characters, which hold no geographic or phylogenetic basis. Additionally, a new species closely related to Atractus sanctaemartae is described from the Atlantic coast of Colombia. It is distinguished from A. sanctaemartae mainly by having two gular scale rows, slender (62% of body diameter) and acuminate head, snout acuminate in lateral view, dorsum uniformly reddish brown and venter cream with a series of rhomboidal blotches arranged linearly on the lateral portion of the ventral scales. We also discuss putative affinities of the new species and A. sanctaemartae on the basis of shared similarity characters, and comment on the occurrence of strong sexually dichromatic coloration in A. sanctaemartae, unique within the genus.

Keywords: SIERRA NEVADA DE SANTA MARTA, GEOGRAPHICAL VARIATION, SEXUAL DICHROMATISM, TAXONOMY

pp. 187-195
Authors: Stamper, C.E.; Stevens, D.J.; Downie, J.R. & Monaghan, P.

Abstract: Many species express different phenotypes when reared under different environmental conditions. However, few studies have considered the possible post-metamorphic effects associated with the induction of particular larval phenotypes in organisms which undergo metamorphosis. In this study, we manipulated both larval density and food availability to create the conditions likely to induce high and low competition morphs in the common frog Rana temporaria and examined the resulting pre- and post-metamorphic phenotypes. Tadpoles reared in a high competition environment took longer to reach metamorphosis, were smaller in terms of both mass and total length and possessed relatively narrow bodies and mouths and short, narrow tails compared to low competition tadpoles. Competition level also influenced swimming ability with high competition tadpoles swimming slower and less far than low competition tadpoles. The effects of high levels of larval competition persisted through metamorphosis; high competition froglets were initially shorter and lighter than those reared under a lower level of competition. In addition, froglets reared under a high level of competition as larvae developed relatively short femurs. However, differences in froglet morphology did not significantly affect performance. These results suggest that factors influencing the phenotype in the larval stage will also have post-metamorphic fitness consequences through influences on post-metamorphic morphology.

Keywords: LIFE HISTORY, DEVELOPMENTAL TRADE-OFFS, RANA TEMPORARIA, SWIMMING ABILITY, PHENOTYPIC PLASTICITY

pp. 197-204
Authors: Cruz, M.J.; Segurado, P.; Sousa, M. & Rebelo, R.

Abstract: Amphibian populations have suffered declines throughout the world due to factors such as habitat destruction, climate change, chemical pollution or the introduction of exotic species. The correct assessment of the declines, as well as of their causes, is dependent on sound monitoring protocols in selected areas, but medium and long-term studies including data before the declines are extremely rare. The red swamp crayfish, Procambarus clarkii, recently introduced to the Iberian Peninsula, is an efficient predator of amphibian embryos and larvae and recent reports have shown that its presence in a water body is a negative predictor of the presence of amphibian breeding populations. Here we compare data from a survey of the amphibian community of the Paul do Boquilobo Nature Reserve, central Portugal, made in 2001, with data gathered in 1992/93, just after P. clarkii arrived in the reserve. The first survey confirmed the presence of 13 species of amphibians in the reserve, four of them very abundant. In 2001, only six amphibian species were recorded, all in extremely small numbers. In only eight years, most of the previously abundant species strongly declined (e.g. Pleurodeles waltl, Triturus marmoratus and Rana perezi) or went locally extinct (e.g. Hyla arborea and Pelodytes punctatus). However, several species that disappeared from the main water body of the reserve continued to reproduce in nearby ponds without crayfish. Crayfish introduction seems the most probable cause for these declines. Therefore, the survival of several Iberian Peninsula amphibian populations may be dependent upon the correct management of the habitats not easily reached by the crayfish.

Keywords: AMPHIBIAN DECLINE, LONG-TERM MONITORING, WETLAND, INVASIVE SPECIES

pp. 205-211
Authors: Gadsden, Hector; Ortiz-Lomas, Cristina; Gil-Martinez, Rosalina; Leyva-Pacheco, Sandra V.; Estrada-Rodriguez, Jose L. & Smith, Geoffrey

Abstract: The reproductive cycle of a population of Sceloporus jarrovii was determined using monthly samples of both sexes collected between April 2004 and March 2005 at the canyon of Las Piedras Encimadas, located in Gómez Palacio, Durango, Mexico. Reproductive activity of both sexes was synchronous, similar to other lizards inhabiting montane zones. Testicular recrudescence began in mid-summer (August), and maximum testicular volume occurred from September to January, declining in February. Testicular recrudescence in volume was negatively correlated with ambient temperature. Females show fall reproductive activity and the reproductive period extended from November to early May. Vitellogenesis occurred from mid fall (November) to early winter (January), with ovulation occurring in late December. Embryonic growth took place from January to May and neonates were observed from May to July. This fall reproductive pattern is common in females from high elevation populations of other viviparous Sceloporus. Mean litter size based on embryos in utero was 6.0±0.32 SE (range 4–8). Litter size was positively correlated with female SVL. Fat body cycles in females and males were similar. Fat bodies in males were largest when maximum reproductive activity occurred, and decreased after the reproductive season. Females contained large fat bodies from October to January, followed by a gradual decrease from late winter to mid-spring. Female fat body mass was not depleted until late May, just prior to parturition. This study adds to our understanding of the reproductive cycle of S. jarrovii, and indicates that fall reproductive activity is a common reproductive strategy among viviparous Sceloporus.

Keywords: PHRYNOSOMATIDAE, VITELLOGENESIS, OVULATION, TESTICULAR VOLUME, SAURIA

pp. 213-222
Authors: Lanzone, C.; Baldo, D. & Rosset, S.D.

Abstract: The Odontophrynus americanus species complex is widely distributed in South America and is formed of diploid and tetraploid cryptic species. We studied the meiotic prophase stages of two allopatric tetraploid population groups from southeastern and northwestern Argentina. These two allopatric population groups showed a bouquet polarization in zigotene and pachytene, and in the latter stage a complete synapsis of quadrivalents and bivalents. In diakinesis, the frequencies of the different elements per cell were recorded and compared with two theoretical distributions for an autotetraploid organism. Both model tests showed the same overall results. The frequency of quadrivalents did not depart significantly from the models in southeastern populations, and must be considered autotetraploid of recent origin. However, northwestern populations have a significantly reduced number of multivalents, which can be explained by diploidization or allotetraploidy. The reduction of quadrivalents is relatively low when compared with one of the models. Additionally, different chiasmatic frequencies were observed between bivalents and quadrivalents in both population groups. The presence of extra chromosomes detected in southeastern populations and the mitotic and meiotic irregularities reported from other populations, not observed in the present study, account for a high cytological variability between populations of the tetraploid frog Odontophrynus americanus, which can be ascribed to polyploidy.

Keywords: POLYPLOIDY, CHIASMATA, BIVALENTS, QUADRIVALENTS, CYCLORAMPHIDAE, ANURA

pp. 223-230
Authors: Vercken, Elodie & Clobert, Jean

Abstract: Colour variation in females is expected to play a role in intra-specific communication by signalling for traits that are socially relevant. However, in some cases, the information carried by colour signals is not sufficient and other cues may be used by conspecifics, such as chemosensory cues. In the common lizard, ventral coloration of females can be classified as yellow, orange or mixed. These ventral colours have been shown to predict the outcome of dyad encounters in an experimental context. However, there was no evidence that females really used the colour signal to assess the competitive ability and the social strategy of their opponent. In lacertids, chemical signals are often implicated in intraspecific communication, and could be used by females to acquire information useful for social interactions. We performed dyad encounters in which the ventral colour of the opponent was either visible or not, and studied the response of the focal female. We found that females used the colour of their opponent as a signal to adjust their own behaviour, but they also seem to be able to use other complementary cues, most probably behavioural cues. Females of different colours also differed in their ability to respond to a novel situation, which suggests colour-based differences in the plasticity of social behaviour.

Keywords: MULTIPLE SIGNALS, LACERTA VIVIPARA, BEHAVIOURAL PLASTICITY, COMPETITIVE INTERACTIONS