Reproductive biology of Cercosaura schreibersii (Squamata, Gymnophthalmidae) and Cnemidophorus lacertoides (Squamata, Teiidae) in Sul-Riograndense shield, Brazil

Abstract

Gonads of 124 specimens of Cercosaura schreibersii (Wiegmann, 1834) and 192 specimens of Cnemidophorus lacertoides Duméril & Bibron, 1839 from the Sul-Riograndense Shield, Rio Grande do Sul, Brazil were analyzed. Both species presented seasonal reproduction, with vitellogenic females found at the end of winter and spring, gravid females in spring and summer and recruitment recorded during the months with the higher mean temperatures in the region. Variation of testis volume was not observed in males of C. schreibersii throughout the year, while adult males of C. lacertoides had variation, with larger testis found in spring. All clutches of C. schreibersii comprised two eggs and data suggest positive correlation between female SVL and egg size (R² = 0.55; p < 0.05). Clutch size of C. lacertoides varied from 2 to 6 eggs (3.75 ± 1.24, n = 15) and positive correlation between female SVL and clutch size was also observed (R² = 0.50; p < 0.001). Females of C. schreibersii had significantly larger SVL than mature males (t-test; p < 0.0001). Head length and width of mature females and males of C. schreibersii were not significantly different. Sexually mature females of C. lacertoides had significantly larger SVL than mature males (t test; p < 0.001), however, males had larger head than females, with significant differences in head length (Ancova; p < 0.001) and width (Ancova; p < 0.001). Juvenile females can attain the size of mature specimens after seven months for C. schreibersii and eight months for C. lacertoides. It was not possible to estimate the sexual maturation age of males, but it is possible to estimate that males are mature earlier and with smaller size than females in both species.