Among vertebrates, amphibians are characterized by a great diversity of reproductive modes, including several forms of parental care. Caecilians, comprising the order Gymnophiona, are one of the most poorly known vertebrate groups due to the their Gondwanan distribution and primarily fossorial habits. Information about their reproductive biology can contribute to overall understanding of amphibians. The present review aims to encourage research on this group by providing an overview of caecilian reproduction, with greater detail on some topics considered relevant in morphology, fertilization, embriology, parental care, ecology, and the evolution of viviparity.

The neotropical frog genus Proceratophrys currently consists of 27 species and only 14 have the advertisement calls described. Herein we describe the advertisement calls of Proceratophrys moratoi based on populations from Minas Gerais State, Brazil and provide an extension to its currently known geographical distribution. Also the advertisement calls of topotypic specimens of P. palustris are described. The analyzed calls of P. moratoi agree with those previously described from São Paulo State and allow this species to be differentiated from the other species in the genus; the calls of P. palustris are very similar to those of P. brauni. Based on the new data for the studied species, we suggest changing the conservation status of P. moratoi to “Data Deficient (DD)” and that of p palustris to “Critically Endangered (CR)”.

Here we provide a detailed description and diagnosis of Apostolepis albicollaris Lema, 2002, a species known from Central Brazil. The species is easily diagnosable from all its congeners by the following combination of characters: a distinctive white nuchal collar (bordered by a narrow black collar), a very broad black lateral streak (from ventral border to 5^th dorsal row), an almost entirely black ventral surface or black with lateral blotches, and 5^th 6^th supralabials in contact with the parietal (temporals 0 0). Apostolepis albicollaris inhabits interfluvial savannas and appears to be the most abundant species of Apostolepis in the region of the type-locality, located within the core area of the Cerrado domain of Central Brazil. Detected patterns of character state distribution supports the inclusion of A albicollaris in a distinct intrageneric assemblage, here named the dimidiata species-group, an inferred clade diagnosed by the following putative synapomorphies: prominent (to strongly pointed) rostral; slightly rounded terminal shield; snout mostly black with small (to indistinct) light spots; upper lip extensively white; and, in most species, absence of nuchal collars. Although superficially closest to A. dimidiata, no putative synapomorphy was found to support a sister-group relationship between these species. Instead, A albicollaris seems to have retained putatively plesiomorphic features suggestive of an ancient divergence relative to other members of the dimidiata species group.

We analyzed the stomach contents of 170 specimens of the colubrid snake Mastigodryas boddaerti collected in the Brazilian Amazon. The Boddaert's Tropical Racer feeds primarily on lizards (N = 57; 74.0%), followed by mammals (N = 11; 14.3%), anurans (N = 5; 6.5%), birds (N = 2; 2.6%), and reptile eggs (N = 2; 2.6%). A significant relationship was found between both snout-vent length and head length of the snakes and prey total length, as well as between snake head width and the width of the prey, and between the weight of snakes and their prey, indicating a tendency for larger snakes to capture larger prey. Differences in the diet were observed between sexes, with females feeding on wider prey and males feeding on larger ones (in terms of body length), which may be related to the longer heads of the males relative to females head. No variation was found between adults and juveniles in the relative size of the prey ingested, although a difference was found in the composition of items, with the adults being more generalist than the juveniles. Twenty-seven of the 61 mature females examined had well-developed follicles and three were pregnant. Prey were found in the digestive tracts of 19 (63.3%) of these breeding females, indicating that they continue to feed during the reproductive period. Our study includes unpublished data on the feeding biology of Mastigodryas boddaerti, increasing the knowledge about the species and contributing to a greater understanding of the ecology of tropical snakes.

Echinanthera undulata is an endemic dipsadid snake from the Atlantic forest in southeastern Brazil. We gathered data on body size, food habits, reproductive cycles, and seasonal abundance of 240 preserved specimens. Adult females are larger in snout-vent length and have shorter tails than males. Males and females do not differ in relative head and eye size. Echinanthera undulata feed mainly on small leptodactylid frogs on the leaf litter. Apparently, its long tail is used to facilitate the capture of prey in this substrate (using poking behavior, leading the anuran to flee in the leaf litter). Reproductive cycle is seasonal in both females and males. Females showed vitellogenic follicles and oviductal eggs mainly at the onset of the rainy season, and births may occur mainly at the onset of the dry season. Fecundity ranged from one to 19 eggs. Testes volume was significantly larger at the end of the rainy season, but the deferent ducts diameter did not differ significantly throughout the year. Variation in seasonal abundance may be related mainly to reproductive events in females and males.

We evaluated the importance of thermal environment and wind intensity to the body temperature (T_b) and activity rates oîLiolaemus lutzae (a lizard species restricted to restingas in the state of Rio de Janeiro, southeastern Brazil), looking for seasonal changes. Field work was carried out in restinga of Praia Grande, municipality of Arraial do Cabo. In the dry season, lizards' activity started (07:00 h) and ended (18:00 h) latter compared to the rainy season (start: 06:00 h; end: 17:00 h). The body temperature of active L. lutzae individuals varied along day (lower in the start and in the end of their daily activity period), and achieved higher values in the rainy season. The lizards' body temperatures were related to substrate temperature and to air temperature in both seasons. Variations in T_b of L. lutzae reflect variations in microhabitat temperatures, the main environmental factors affecting its thermoregulation. The wind intensity affected the T_b of L. lutzae, promoting heat loss by individuals. The mean wind intensity per transect influenced the number of lizards in the habitat causing diminishment. Evaluation of our data indicated that seasonal variations, thermal environments, and wind speed influence both body temperature and activity rates of lizards.

Annual and daily activity patterns of Dipsas bucephala from southeastern Brazil were characterized respectively from the Instituto Butantan (São Paulo, Brazil) collection data over a 21-year period and from individuals video-monitored in laboratory continuously. D. bucephala was more frequently collected in summer (second half of the rainy and warm season) with a peak in March, which indicates a seasonal and unimodal activity pattern. Temperature and precipitation seems to explain only a part of this variation. Prey availability throughout the year and reproductive events are other factors likely to shape this pattern. Higher activity in the summer would be synchronic to a higher mollusk abundance. Gravid females were found only during spring. Thus, the peak of activity in late summer may be related to an increase in male activity due to mate search. Daily activity occurred during the nocturnal period (between 17:30 and 06:00 h). Peaks were unimodal, registered between 19:00 and 02:00 h, and were longer than those observed in other snakes. This extensive activity period may be related to an intensive foraging activity in malacophagous snakes. Moreover, peaks of daily activity were higher when food was available. The lack of chemical stimulus (mucus trail) may explain the lower peak of activity in experiments without food.

Following examination of recently collected and older specimens of Riama from southern Ecuador, we report morphological variation in R. vespertina and modify the species diagnosis and description accordingly; furthermore, we describe two new species, comment on additional diversity of the genus in this region and discuss some character-states, specially dorsal scale relief (specifically striated and keeled conditions). We provide an identification key to the species of Riama occurring in southern Ecuador.