SEXUAL DIMORPHISM IN LYSAPSUS BOLIVIANUS (ANURA: HYLIDAE) IN AN AMAZONIAN FLOODPLAIN

Sexual dimorphism (SD) in morphology may be attributed to a variety of ecological pressures, including sexual selection, differential growth rate, age at maturity, longevity, and niche partitioning. This morphological variation between the sexes can help us better understand the evolution of life histories and fill gaps about species/populations from less-explored regions. We investigated sexual dimorphism in morphometric characters of Lysapsus bolivianus from a floodplain environment in Eastern Amazon based on 273 specimens collected between 2013 to 2019. Females of L. bolivianus attain larger body sizes (Snout-to-Vent Length), but males have proportionally higher heads than females. Previous studies indicate that SSD in L. bolivianus can be linked to differential growth rate and age to maturity between sexes, whereas differences in head morphometry can be explained by differences in prey volume ingested by males and females. Nevertheless, the species inhabits a highly seasonal environment and bear a high pressure of predation. In this sense, males and females may cope with different selective pressures due to size differences.