Sexually Dimorphic Skin Glands in the Invasive Species Lithobates catesbeianus (Anura:Ranidae)

MANCINELLI SAM; CÓCERES A; POZZI AG; JUNGBLUT LD

AMPHIBIA-REPTILIA

BRILL ACADEMIC PUBLISHERS

Lugar: Leiden; Año: 2021

0173-5373

Males of most amphibian species possess specialized cutaneous glands, known as sexually dimorphic skin glands (SDSGs). SDSGs are usually clustered in specific body regions and are externally visible, but in some cases, external differences between males and females can be slight or absent, and the occurrence of SDSGs can only be disclosed by histological studies. Chemical signals produced by SDSGs markedly affect amphibian behavior and reproduction, and therefore their occurrence, features and location in the body could provide information on potential mechanisms of intraspecific communication in a particular species. In the present study, we perform light microscope (both histological and histochemical), and scanning electron microscope studies of skin samples from male and female specimens of the invasive frog Lithobates catesbeianus (the American bullfrog), covering several body regions that could hold SDSGs. Most skin areas analyzed showed only ordinary serous and mucous glands despite remarkable sexual dimorphism that could be externally observed. Instead, the male nuptial pads contained exclusively hypertrophied, specialized mucous glands, closely resembling breeding glands described in other anurans. Our histochemical study revealed that these specialized mucous glands contain heterogeneous populations of secretory cells, possibly involved in pheromone production.