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Mar del Plata, Argentina

Dominguez-Lopez M.E.,Seccion Herpetologia | Ortega-Leon A.M.,University of Cordoba, Spain | Zamora-Abrego G.J.,National University of Colombia
Revista Chilena de Historia Natural | Year: 2015

Background: Caudal autotomy appears to be an adaptation strategy to reduce the risk of being preyed upon. In an encounter with a predator, the prey must reduce the risk of being preyed upon, and one of the strategies that has exerted a strong pressure on selection has been tail loss. In lizards, it has been demonstrated that tail loss reduces the probability of survival in the event of a second attack; therefore, they must resort to new escape strategies to reduce the risk of falling prey. In order to evaluate the effect of tail loss on the escape behavior of Gonatodes albogularis in natural conditions, we took samples from a forest interior population. We expected that individuals that had not lost their tails would allow the predator to get closer than those that had lost it. For each sample, we recorded the following: (1) escape behavior, measured through three distances (e.g., approach distance, escape distance, and final distance); (2) distance to shelter; and (3) length of tail. We included only males in the study since we did not record any females without a tail and far fewer with a regenerated tail. Results: We found that tail loss does have an effect on the escape behavior of G. albogularis. Males that have their tails intact allow the predator to come closer, and we found a negative correlation between the approach distance and the length of the tail. Conclusion: Our results support the escape behavior theory, in which G. albogularis males drop their tails when the risk of predation is much higher than the cost of fleeing. © 2015 Domínguez-López et al.;.

Candioti F.V.,CONICET | Haad B.,CONICET | Baldo D.,Institute Herpetologia | Baldo D.,National University of Misiones | And 3 more authors.
Biological Journal of the Linnean Society | Year: 2011

The oral apparatus of anuran tadpoles is a unique structure composed of soft and keratinized parts surrounding the mouth. Among the many variations, a common oral apparatus involves a dorsal gap in the marginal papillae, keratinized jaw sheaths, and two upper and three lower rows of labial teeth. In Leiuperidae, besides this generalized morphology, four configurations are distinguished by the arrangement of the lower marginal papillae and the number of lower tooth rows. Study of the early oral ontogeny in 12 species representing these five configurations shows variations in the development of the lower marginal papillae and the third lower labial tooth row. Similar configurations may result from similar pathways (e.g. Physalaemus cuvieri group and Pseudopaludicola falcipes) or different pathways (e.g. generalized oral discs of Pleurodema and Physalaemus). Different oral configurations may result from overlapping trajectories ending at different stages (e.g. Physalaemus riograndensis and Ph.biligonigerus) or different trajectories (e.g. Ph.henselii and Ph.gracilis). Further studies are needed to interpret the role that heterochrony has played in evolutionary change within this family. The unsuspected variation occurring in this transient structure highlights its evolutionary potential and might be insightful in studies of anuran phylogenies that are largely based on adult characters. © 2011 The Linnean Society of London.

Guerra C.,CONICET | Baldo D.,CONICET | Baldo D.,National University of Misiones | Rosset S.,National University of La Plata | And 2 more authors.
Zootaxa | Year: 2011

The Rhinella granulosa group currently includes 12 species distributed eastern to the Andes, from Panama to central Argentina. We studied bioacoustic features of the advertisement calls in seven of these species: Rhinella azarai, R. bergi, R. centralis, R. dorbignyi, R. fernandezae, R. major, and R. merianae. In addition, we analyzed the release calls of R. azarai, R. bergi, R. dorbignyi, and R. fernandezae. The advertisement calls consisted of long trills, composed by notes with a variable pulse number (2-8) that was characteristic of each species. The release calls consisted of a single note, pulsed or not. Both advertisement and release calls clearly varied between species, except for R. dorbignyi and R. fernandezae. The study of specimens sharing exosomatic characters with R. bergi and R. major from a syntopy area, which presented intermediate spectral and temporal call parameters, confirmed natural hybridization between these two species. Copyright © 2011 · Magnolia Press.

Baldo D.,Institute Herpetologia | Baldo D.,National University of Misiones | Borteiro C.,Seccion Herpetologia | Kolenc F.,Seccion Herpetologia | And 3 more authors.
Zootaxa | Year: 2012

Melanophryniscus orejasmirandai is a species of toad known only from two localities in southern Uruguay. This toad is the southernmost suggested taxon of the M. tumifrons group, whose species are characterized by a glandular frontal swell-ing on the snout. The study of the type series of M. orejasmirandai and of M. pachyrhynus, along with observations made on many specimens of both species suggested a close relationship between them. The analysis of the variation of snout-vent length, coloration pattern, relative size of the frontal swelling, and presence/absence of the metatarsal gland showed that characters previously used to separate both species resulted of no diagnostic value. Further comparison of the external morphology, osteological characters, and partial sequences of the cytochrome b gene indicated that M. orejasmirandai is a junior synonym of M. pachyrhynus. Melanophryniscus pachyrhynus is characterized by a reticulated orange ventral pat-tern which is shared only with M. peritus, from which it differs by its smaller size. The ornamentation of the nasal bones underlying the frontal swelling in M. pachyrhynus seems to be characteristic of the M. tumifrons group. An updated dis-tribution map of M. pachyrhynus and some new localities are also provided. Copyright © 2012 Magnolia Press.

Borteiro C.,Seccion Herpetologia | Kolenc F.,Seccion Herpetologia | Prigioni C.,Seccion Herpetologia | Lyra M.L.,Claro | Baldo D.,National University of Misiones
Zootaxa | Year: 2013

The main goal of this manuscript is the reevaluation of the taxonomic status of the teiid lizard Contomastix charrua, known only from Cabo Polonio, a small coastal rocky outcrop in southeastern Uruguay. This species was erected on the basis of the presence of a second pair of ceratobranchials and longer cornua in the hyoid bone, in addition to a reduced expression of the pattern of coloration as compared with C. lacertoides. Nevertheless, we found that both species have indistinguishable hyoid morphology, bearing C. lacertoides a noticeable second pair of ceratobranchials. Besides, we realized that the pattern of coloration in this species is more variable than previously considered. As a result of the present work, C. charrua is included in the synonymy of C. lacertoides. In addition, we provide some observations on the holotype of Cnemidophorus grandensis, a junior synonym of C. lacertoides. Copyright © 2013 Magnolia Press.

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