Estimating total systemic blood flow based on measurements from a single aortic arch is common practice in cardiovascular studies on reptiles to avoid heavy instrumentation and consequent stress responses. This practice requires the validation of a specific correction factor that expresses the relationship between the measured blood flow and the blood flow to be estimated. Misleading estimations may occur when correction factors are used in different conditions from those they were originally measured. Despite recognized as a problem, such misleading estimations are common in physiology. In the present study, we derived values for correction factors to estimate systemic blood flow in the South American rattlesnake, Crotalus durissus, following recovery from anesthesia, using serial measurements of blood flow in the three main systemic arteries, left or distal right aortic arches and the carotid artery. Blood flow recorded in the left aortic arch provided the most reliable and less variable correction factors. Different from previously published, blood flow distribution in the systemic circulation varied with temperature. We suggest the use of the specific correction factors present in this paper for different experimental protocols and temperatures. Furthermore, we can affirm that unilateral left vagotomy, which effectively ablated control of right-left shunts, does not affect systemic blood flow distribution, so the same correction factors can be used.

The genus Pseudis (Hylidae) includes aquatic frogs distributed throughout South America east of the Andes. Few papers have been published on the ecology of these species, despite the great interest their gigantic larvae raise among herpetologists. Pseudis tocantins has a widespread distribution along the Tocantins-Araguaia hydrographic basin in Brazil and virtually nothing has been published about its natural history and ecology. The present work aimed to evaluate, based on 159 specimens from 13 populations, sexual dimorphism in size and shape and diet composition of P. tocantins along most of its known distribution. Females were significantly larger than males and body shape differed significantly between sexes, with tibia length and tympanum diameter as the variables contributing the most to this difference. We found 13 prey categories in frog’s stomachs, with Araneae, Odonata, and Orthoptera being the most important items, respectively. Aquatic animals were also part of the species diet (even though less representative than non-aquatic prey), showing that P. tocantins feeds on both above water and subaquatic prey.

The anole lizards represent a conspicuous group of vertebrates due to their high species number and abundance in different habitats. Despite the high richness of anoles in Mexico (48 species), to date only a few studies have been performed on their ecology. Because different groups of parasites can provide ecological information on their hosts, we studied the helminths parasitizing Anolis uniformis, one of the most common anoles from southern Mexico. We examined individuals from the tropical rainforest in Laguna Escondida, Los Tuxtlas, Veracruz and we found eight parasitic taxa: seven nematodes (Acuariidae gen. sp., Aplectana sp., Oswaldocruzia sp., Physocephalus sp., Piratuba sp., Rhabdias tobagoensis, and Strongyluris panamaensis) and one acanthocephalan (Centrorhynchus sp.). All taxa represent new records for the host. Additionally, the genera Centrorhynchus, Oswaldocruzia, Physocephalus and Strongyluris are new records for Mexican anoles, while the genus Aplectana is a new record for all anoles. At the genus level, the taxonomical composition of the helminth fauna of A. uniformis is similar to that reported for Central and South American anoles. The life cycles of the parasites found suggest that these lizards may acquire most nematodes from the forest floor while hiding. Life cycles also support that A. uniformis has a mainly insectivorous diet and reflect the presence of mosquitoes that transmit microfilariae to the lizards when feed on their blood.

We describe a new species of anuran belonging to the Rhinella crucifer species group, from a relictual Atlantic Forest fragment located at the Serra de Baturité mountain range, State of Ceará, Northeastern Brazil. The new species is characterized by narrow and elongated parotoid glands, overhanging the lateral edges of the body dorsally; a conspicuous fringe on the ventral surface of the tarsus; yellow marks on the flanks of the posterior surface of thighs and cloaca; integument of the dorsum and limbs with round warts with many keratinized black spines. Tadpoles have a kidney-shaped nostril, with a dorsal fin that begins low and rises acutely once passed by the body limits; oral disc laterally emarginated, sub-marginal papillae clumped, dark papillae in some specimens. In addition, we describe call parameters of the new species, provide information regarding its natural history, and comment on its conservation status.

To assess the conservation status of endemic species we examined the population trends in three frog species with different life histories. We performed a mark-recapture field experiment in a protected area on the eastern flank of the Cordillera Central in the northern Andes of Colombia. We marked and followed 123 individuals of Pristimantis jaguensis, 178 Colostethus aff. fraterdanieli, and 83 Dendrobates truncatus. The survival probability and the population growth rate of P. jaguensis varied as a function of capture occasion, while the recapture probability was constant. In the two dendrobatids, C. aff. fraterdanieli and D. truncatus, survival and recapture probabilities were constant over time and the population growth rate indicated the populations were stables during monitoring. Long-term monitoring programs are recommended to establish with certainty the conservation status of each species. However, in the perspective of the current biodiversity crisis in which rapid management decisions must be made, it is necessary to draw on the available data even if its limited. Although our demographic dataset is limited in time, we demonstrated how this information constitutes a starting point to understand the conservation status of these frog populations and to establish standard methods to continue long-term monitoring programs.

The horned frog family, Ceratophryidae, currently comprises three genera and 12 extant species, distributed from the Caribbean lowlands to the Pampean grasslands. Horned frogs are fossorial species that are remarkable in terms of their adult and larval morphology, karyotype, behavior, and other aspects of their biology. In this paper we present a molecular phylogenetic analysis with the goals of: (1) exploring the relationships among the species of Ceratophryidae; (2) studying the evolution of polyploidy; (3) studying the evolution of cocoon formation and larval development duration associated with surviving in semiarid environments; and (4) reviewing the ceratophryid fossil record that could be relevant as calibration points in molecular divergence estimations. The analysis included 11 of the 12 extant species and, when possible, multiple exemplars per species, as well as multiple outgroups. Sequence data were obtained on seven mitochondrial and six nuclear genes for up to 8200 bp per specimen. Our results indicate that the individual monophyly of Ceratophrys and Lepidobatrachus is well corroborated. The monotypic Chacophrys is recovered as the sister taxon of Lepidobatrachus, but with Jackknife frequency < 50%. Lepidobatrachus asper is the sister taxon of L. laevis L. llanensis. Relationships within Ceratophrys are congruent with an earlier proposal, with a clade composed of the species possessing a dorsal bony shield (Ce. aurita, Ce. cranwelli, Ce. joazeirensis, and Ce. ornata), and another clade composed of Ce. stolzmanni, Ce. calcarata, and Ce. cornuta. Unlike earlier proposals, the octoploid species (Ce. aurita, Ce. joazeirensis, and Ce. ornata) are not monophyletic, as the diploid Ce. cranwelli, and Ce. ornata are sister taxa. This result implies an ambiguous optimization of ploidy levels, with either a single origin of octoploidy with a subsequent reversal to diploidy, or two independent origins of octoploidy being equally parsimonious; both alternatives are quite unusual from the perspective of chromosome evolution. Our results suggest that ceratophryids diversified in semiarid environments and three independent events resulted in three species subsequently occupying temperate or tropical humid areas. This early diversification in semiarid areas explains the retention of characteristics associated with these environments (like the production of a cocoon of dead skin during estivation, and possibly an accelerated larval period and development) in species present in humid areas. A revision of the fossil record of this family of frogs indicates that there are only two fossil remains that could serve as calibration points for molecular clock estimation, but a number of issues associated with them preclude their use.

A new salamander of the genus Chiropterotriton is described from the Sierra Madre Oriental in southwestern Tamaulipas, Mexico. This genus is widespread in the Sierra Madre Oriental, its range extending from Tamaulipas to northern Oaxaca, and it occurs into central Mexico along the mountains associated with the Transverse Volcanic Axis. The species described herein is one of the northernmost species. Previously a few species of Chiropterotriton have been reported from the mountains of Tamaulipas and adjacent Nuevo León, but this new salamander is easily distinguished by its enlarged nares. It also differs from all congeners by a combination of characters including size, limb length, hand and foot morphology, color pattern, and dental morphology.

Wetlands of southern Brazil exhibit unique habitat attributes, such as climate pattern and vegetation cover, that can function as an environmental filter for the establishment of species of Neotropical anurans and influence the composition of anuran assemblages. We examined the role of habitat heterogeneity in the composition and relative abundance of anuran species in subtemperate wetlands of southernmost Brazil. We carried out standardized sampling between May 2009 and April 2011 to examine anuran assemblages in marshes associated with grasslands and coastal dunes, as well as habitat heterogeneity. Habitat heterogeneity and anuran species richness were higher in grasslands. Abundance and species dominance, on the other hand, were higher in dunes. This might be due to more restrictive abiotic filters in dunes, such as the low heterogeneity of vegetation cover and lower availability of water bodies. The most common species in grasslands, Leptodactylus cf. latrans, Elachistocleis bicolor, and Pseudis minuta, exhibited a stronger association with habitats with larger and deeper water bodies and with the presence of floating vegetation. The most abundant species found in dunes, Rhinellla arenarum, Odontophrynus maisuma, and Physalaemus biligonigerus, had a stronger association with low vegetation. In addition to habitat associations, the ability to bury themselves might be a behavioral adaptation to dunes that favor species such as O. maisuma and P. biligonigerus, even under extreme microclimatic conditions. Our findings support the importance of the configuration of vegetation cover as well the heterogeneity of water bodies for the establishment of anuran species in subtemperate marshes of southern Brazil.