First record of twin hatchlings in Caiman latirostris (Daudin, 1802) in the Atlantic Forest, Brazil

Embryo twinning is quite common in reptiles, possibly due to atypical incubation conditions, although few specimens hatch and reach adulthood, especially in the wild. In crocodilians, eggs with double yolk or monozygotic twins are usually produced by young females and laid at the beginning or end of oviposition. This phenomenon mostly happened in the Crocodylidae and Alligatoridae families, with double yolk and Siamese twins. This scientific note aimed to report the first record of twinning caimans in the Brazilian Atlantic rainforest from a Caiman latirostris clutch, found during the 2021 nesting season in Tapacurá Ecological Station, hatched on May 6th. Both twins were healthy and without deformities, just slightly lighter and smaller than the average of the nest, which may compromise their survival until sexual maturity, since bigger hatchlings tend to have a higher survival rate than smaller ones, even considering that nesting females react more to the vocalization of smaller specimens.