On the natural history of Leptodactylus syphax with comments on the evolution of reproductive features in the L. pentadactylus species group (Anura, Leptodactylidae)

We describe the reproduction of Leptodactylus syphax from Brazil and attempt to trace the evolution of reproductive traits within the L. pentadactylus species group. We quantified the proportion of eggs/embryos from fresh nests. We test whether L. labyrinthicus and L. syphax tadpoles can prey on eggs from heterospecific foam nests. Egg clutches were found outside the water at the edges of rocky/seasonal streams, usually within excavated basins. Males beat the foam with their legs moving from side to side. Clutches do not have trophic eggs, since most of their eggs develop into tadpoles. Tadpoles cling on rocks in current/shallow waters. Only L. labyrinthicus tadpoles could prey on eggs from heterospecific foam nests. If the L. pentadactylus group is monophyletic, excavated basins and foam-beating in lateral motions may be possible synapomorphies of this group. However, large adults, carnivorous tadpoles and trophic eggs appear to be associated synapomorphies of a less inclusive group.