Cochranella buenaventura sp. nov. is described from the southern foothills of the Cordillera Occidental, Andes of Ecuador. The new species inhabits the Seasonal Foothill Evergreen forests of the province of El Oro, in the West Ecuadorian biogeographic region. This species is distinguished from other species of glassfrogs by having a truncate snout in dorsal and lateral views, reduced webbing between fingers, absence of guanophores on the digestive visceral peritonea, but present on the renal capsule, absence of humeral spine, green dorsum in life with scattered pale yellow spots, bright yellow hands and feet discs, and moderate body size (20.9-22.4 mm snout-vent length in adult males).

The present study analyses the sequence of metatarsal and phalangeal bone formation in Podocnemis expansa. The ontogenetic sequence studied comprises 24 embryos collected at 5-days intervals in various stages of prenatal development, starting from the 18^th day of natural incubation. Biometric measurements were taken and the embryos were cleared and stained with alizarine for bone visualization, followed by the Davis and Gore method. Each pe has five metatarsals (M) and 14 phalanges, two on the fifth finger and three on each of the other fingers, with a phalangeal formula of 3:3:3:3:2. Retention of the stain in metatarsals occurs in the following order: M III > M II = M IV > M V > M I. In stage 20, it is evident that the ossification center progresses in the direction of the epiphyses in all metatarsals. The sequence of stain retention in distal phalanges (DP) occurs in the following order: DP V > DP IV > DP III > DP II > DP I. In the medial phalanges (MP), the stain retention sequence is MP III > MP IV > MP II > MP I. Lastly, the proximal phalanges (PP) retain staining in the following sequence: PP V > PP I > PP II > PP III > PP IV. Differences and similarities in synchronization of ossification in Podocnemis expansa and comparable species are evident. The lack of a common osteogenetic pattern among all chelonians is due to variations in the initial site of bone formation and sequence of ossification.

We hypothesized that species that overlap in calling sites partition the acoustic space, whereas those that segregate calling sites overlap in the acoustic space. Most of the 12 analyzed species (75%; n = 9 species) were generalists with respect to at least one of the calling site variables, a characteristic of species living in unpredictable or human-altered habitats. In most water bodies, segregation in calling sites occurred as a result of low species richness in the communities. Higher overlaps in calling sites were observed among species that called from the ground or while floating in water than among those that called perched on vegetation, probably due to differences in the use of two- versus three-dimensional spaces. As a result of the analysis of similarity among advertisement call features, we observed higher segregation among species that called on the ground or floating on water than perched on vegetation. For those species, differences in advertisement calls seem to explain their coexistence.

We studied the reproductive characteristics of a population of Gonatodes albogularis in an Andean tropical dry forest with a bimodal rainfall regime. Females were smaller than males in snout-vent length (SVL). Males and females reached sexual maturity at similar body sizes (close to 31 mm SVL) and had continuous reproductive activity during the sampling year. All adult females were reproductive (vitellogenic and gravid females); they were found throughout the year and we did not observe differences among months in reproductive stages, nor in the follicular and ovarian sizes. Gravid females produced only one egg and had simultaneously one large vitellogenic follicle, suggesting a continuous reproductive activity. Adult males had spermatozoa in testes and ducts during all months and there were no significant changes among months in the volume and mass of testes adjusted to body size. These data, plus the observation of neonates and communal nests in every month of the year, confirm a pattern of continuous reproductive activity with multiple clutches. Despite the low mean annual rainfall, and the marked seasonality of rainfall in the area, the population exhibited an aseasonal reproductive pattern that suggests a continuous availability of resources for reproduction.

This work analyses the influence that nest site characteristics have over natural incubation in freshwater turtles Podocnemis expansa and Podocnemis unifilis. Results indicate that neither carapace size nor weight of P. expansa hatchlings depends on environmental characteristics. This suggests that incubation occurs in a homogeneous environment in terms of moisture. On the other hand, embryonic development of P. unifilis is affected by soil moisture, and nests located in very humid beach areas generate smaller hatchlings than nests incubated in drier areas.

A new species of the genus Chiasmocleis is described from the Reserva Sapiranga, an Atlantic Rain Forest remnant in the Municipality of Mata de São João, northeastern State of Bahia, Brazil. This species belongs to the C. leucosticta group, characterized by well-developed webbing on feet. Chiasmocleis sapiranga sp. nov. is diagnosed by having the fingers extensively fringed in males and only slightly fringed in females, and by the dorsal region uniformly dark brown and ventral region finely marbled in brown and pale cream.

Reproductive (sexual dimorphism, reproductive maturity, reproductive cycle, recruitment and fecundity), feeding biology (diet composition and frequency of food items) and morphology data (body size and tail breakage) of Dendrophidion dendrophis are presented, based on the analysis of 95 specimens (61 males and 34 females) from different regions of Brazilian Amazon. There were no significant differences in the snout-vent length and tail length between males and females. Males reach reproductive maturity with a smaller snout-vent length than females, which become sexually mature when they reach approximately three times the size of the newborns. A positive, yet only slightly significant, relationship was observed between the number of vitellogenic follicles and eggs and the snout-vent length of the females. Reproductive activity occurs throughout the year, suggesting aseasonal breeding for the species. The high incidence of broken tail or visible rupture points in mature and immature males and females corroborates the hypothesis of tail breakage as a defense mechanism in this species. All food items found were frogs of the subfamily Leptodactylinae (family Leptodactylidae), most often from the genus Adenomera, followed by Physalaemus, suggesting that D. dendrophis is primarily terrestrial and anurophagous.

Areas of endemism are considered the fundamental unit in historical biogeography because they are the entities to be compared in biogeographic analysis. However, until recently, there were no formal methods for its identification. In this paper, I applied two different methods for the identification of areas of endemism of the genus Liolaemus, the parsimony analysis of endemicity (PAE), and a recently proposed method based on an optimality criterion implemented in the computer program NDM. I analyzed the distributions of 29 species of Liolaemus inhabiting the Puna region in Northwestern Argentina. The analysis with NDM found four areas of endemism that show a repeated pattern of species groups, with the same groups in each area. On the other hand, results generated through PAE were not congruent with those of NDM and sometimes violated the definition of endemism. The patterns found suggest that these groups of species could have been affected by the same historical events.

The external morphology and oral disc of the tadpole of Leptodactylus notoaktites Heyer, 1978, are described and illustrated for Gosner's stage 33. The internal oral anatomy was analyzed under SEM at Gosner's stage 36 whereas chondrocranial anatomy is reported for Gosner' stage 38. The morphology of this tadpole is compared with those available for other species of the L. mystaceus complex. The overall characteristics do not depart from those known for the genus Leptodactylus and they particularly agree for those of the fuscus species group. The labial tooth row formula is 2(2)/3.

We report the youngest record of the Cretaceous snake Dinilysia, from the Late Cretaceous (Campanian) Anacleto Formation (Campanian) of Neuquén province, Argentina. The specimen consists on twenty four articulated mid-posterior trunk vertebrae with the base of their respective ribs. The specimen is refered to Dinilysia on the basis of several morphological features, including a triangular shape of the vertebral body, straight posterior border of the neural arch, large craniocaudal extension of the neural spine, absence of parazygantral foramen, and arqual ridges. This represents the youngest record of the genus Dinilysia, thus extending its biochron up to the Campanian age.