Reproduction of Pseudis minuta (Anura, Hylidae) in southern Brazil

Abstract

This study was based on individuals of Pseudis minuta captured or observed in the municipality of Candiota, Campanha region of the state of Rio Grande do Sul, southern Brazil. Sampling occurred along ten non-consecutive months in 2000, 2001 and 2002. The reproductive phases were characterized based on the gonadal development stage of 39 males and 50 females, and on the observation, in nature, of the seasonal distribution of calling males, occurrence of amplectant pairs, and presence of larvae, juveniles and adults. Calls were recorded from August to April, amplectant pairs from October to February (except January), tadpoles from October to March (except February), and juveniles in all the sampled months (except January). Reproductive activity was not observed in late fall and early winter, even though females with post-vitellogenic oocytes and males with spermatozoa in the seminiferous tubules were recorded in all the seasons. Mature females were statistically larger and heavier than mature males. The smallest female with post-vitellogenic oocytes had 32.0 mm of snout-vent length, and the smallest male with spermatozoa in its seminiferous tubules had 20.6 mm. The number of post-vitellogenic oocytes was directly proportional to the mass and to the snout-vent length of females, and the length of testis was directly proportional to the snout-vent length and to the mass of males.