gonzagai (no common name) is a recently described phyllomedusid in northeastern Brazil. Given its recent description, many aspects of its biology are completely unknown. Here we describe the reproductive behavior of P. gonzagai through the characterization of oviposition sites, the process of egg deposition, and the behavior of individuals in amplexus, and we evaluate the occurrence of assortative mating. We collected data in February-May of 2017 in the municipality of Groairas, Ceara state, northeastern Brazil, in an area of Caatinga sensu stricto. Oviposition occurred predominantly in leaves of Euphorbiaceae (53.8%, n = 14) and Poaceae (23.08%, n = 6). The height of the selected plants averaged 102.3 cm, the leaves selected for oviposition averaged 69.1 cm from the water surface, and the depth of water below the eggs averaged 16.6 cm. Oviposition duration averaged 48.5 min (n = 12), and clutch size averaged 102.6 eggs (n = 12), with a mean proportion of 96.2% of eggs fertilized. Males in amplexus interacted acoustically with neighbors. We also recorded cases of multiple males in amplexus and reactions of amplected males to the intrusions by rivals. Body mass and length of males in amplexus (n = 7) did not differ significantly from those of non-amplected males (n = 11). We found, however, a positive relationship between the mass of males and the mass of females paired in amplexus (n = 12), which suggests assortative mating. Our results expand the knowledge on the life history of frogs in the genus Pithecopus and the family Phyllomedusidae.