Reproductive biology of Echinanthera cyanopleura (Serpentes: Dipsadidae) in southern Brazil

The reproductive cycles of snakes can be influenced by many factors, both biotic and abiotic, and information about these factors can contribute significantly to knowledge of the biology of many species. Here, we present data on the reproductive biology (body size, sexual dimorphism and female reproductive cycle) of the forest-dwelling colubrid Echinanthera cyanopleura (Cope, 1885), based on analyses of 128 specimens preserved in collections and originating from the states of Paraná, Santa Catarina, and Rio Grande do Sul in southern Brazil. The snout-vent length of females was significantly greater than in males. The tail length of mature females was greater than in males, although this difference was not significant. Vitellogenesis occurs from August to December and eggs were found in greater frequency from October through December. Juveniles were found in larger numbers beginning in February, indicating that recruitment occurs from January to April. The reproductive cycle of this species is seasonal, which is usual for oviparous colubrids of temperate areas of Brazil

Reproductive biology of Leptodactylus fuscus (Anura, Leptodactylidae) in the subtropical climate, Rio Grande do Sul, Brazil

The aim of this study was to characterize, for the central region of the State of Rio Grande do Sul, Brazil, the reproductive biology of Leptodactylus fuscus (Schneider, 1799), based on the analysis of gonadal development of males and females, reproductive effort, size-fecundity relationships, and occurrence of sexual dimorphism in body size. Mature individuals were found from October 1996 to February 1997 and from October 1997 to December 1997. The highest input of juveniles in the population was recorded in March 1997. There was a positive and significant correlation between the number of mature individuals and the mean monthly temperature. The population did not present sexual dimorphism in size. Males presented significant correlation only between snout-vent length and testes length. All females had oocytes at four different maturation stages and there were no significant correlations regarding size-fecundity variables. The correlation between ovarian size factor and females snout-vent length was not significant either. The main difference between this population and those that inhabit tropical climate was that temperature was responsible for stimulating the reproduction activity, instead of rainfall.<br>O objetivo do estudo foi caracterizar, para a região central do Rio Grande do Sul, a biologia reprodutiva de Leptodactylus fuscus (Schneider, 1799) a partir da análise do desenvolvimento gonadal de machos e fêmeas, esforço reprodutivo, relações de tamanho-fecundidade e existência de dimorfismo sexual em relação ao tamanho corporal. Indivíduos maduros foram encontrados de outubro/1996 a fevereiro/1997 e outubro/1997 a dezembro/1997. Em março de 1997, houve o maior acréscimo de indivíduos jovens na população. Houve correlação positiva e significativa entre o número de indivíduos maduros coletados e a temperatura média mensal. A população não apresentou dimorfismo sexual. Para os machos, houve correlação significativa apenas entre comprimento corporal e comprimento dos testículos. Todas as fêmeas possuíam ovócitos em quatro diferentes estágios de maturação e não foi observada nenhuma correlação significativa entre as variáveis de tamanho-fecundidade. A correlação entre fator tamanho do ovário e comprimento corporal também não foi significativa. A principal diferença entre esta população e as que habitam clima tropical foi o efeito da temperatura como estímulo da atividade reprodutiva, ao invés de chuva