New insights into sexually dimorphic skin glands of anurans: The structure and ultrastructure of the mental and lateral glands in Hypsiboas punctatus (Amphibia: Anura: Hylidae)

Abstract

Many anuran species are characterized by sexually dimorphic skin glands. These glands often are concentrated on specific areas, such as the mental region, flanks, or the nuptial pads. We studied the histology and histochemistry of mental and lateral glands in Hypsiboas punctatus, and compared them to skin from other body regions. We describe four types of dermal glands, two types of mucous and two types of serous glands. The mucous glands are formed by a single layered epithelium. The mucocytes surrounding a central lumen are filled with polyhedral granules. Ordinary mucous glands are small sized glands with cubical epithelium, mucoid content, and small granules. Specialized mucous glands are characterized by a larger size, a columnar epithelium, a proteinaceous content and larger granules. Both types of serous glands are syncytial and share some structural features including size, shape, and morphology of secretory granules. However, ordinary and specialized serous glands differ in their histochemical properties, size and appearance of secretory granules, and glandular outlets. The specialized type of mucous glands in H. punctatus resembles most SDSGs described in anurans, whereas the presence of specialized serous glands that are sexually dimorphic is less common. Both specialized glands occur only in mental and lateral regions of males, whereas ordinary mucous and ordinary serous glands occur in males and females.

Diversity and evolution of sexually dimorphic mental and lateral glands in Cophomantini treefrogs (Anura: Hylidae: Hylinae)

“…() and Brunetti et al . (). For descriptions at microscopic levels, we have followed Romero de Perez & Ruiz Carranza () and Brunetti et al .…”

“…In particular, recent studies in Cophomantini show that mental glands are more frequent than previously reported (Faivovich et al ., , , ; Faivovich & De la Riva, ; Faivovich, McDiarmid & Myers, ), whereas Brunetti et al . () have also demonstrated the presence of lateral glands co‐occurring with mental glands in Hypsiboas punctatus , a species of the H. punctatus group.…”

“…By contrast, published accounts of SDSGs in anurans have been limited to comments detailing their occurrence, with few histological descriptions (Brizzi et al ., ). Even though there is an increasing interest in the structure and ultrastructure of these glands (Vences et al ., ; Gonçalves & Brito‐Gitirana, ; Siegel et al ., ; Brunetti et al ., ), knowledge of their diversity, taxonomic distribution, and evolution remains poor.…”

Comparative analysis of the integument of different tree frog species from Ololygon and Scinax genera (Anura: Hylidae)

“…Nevertheless, various subtypes of serous glands with high morphological variability have been reported (Goniakowska-Witalinska and Kubiczek 1998, Delfino et al 1999, Warburg et al 2000, Nosi et al 2002, Brunetti et al 2012, Moreno-Gómez et al 2014.…”

Extended Vocal Repertoire inHypsiboas punctatus(Anura: Hylidae)

“…Knowledge of the reproductive biology of H. punctatus is limited to some references to its advertisement call (Barrio, 1965;Duellman, 1978;Hoogmoed, 1979;Lescure and Marty, 2001) and call comparison with the morphologically similar species Hypsiboas atlanticus (Napoli and Cruz, 2005). The presence of two types of sexually dimorphic skin glands (SDSGs) in mental and lateral body regions suggests some sort of chemical communication during courtship and/or male interactions (Hoogmoed, 1979;Brunetti et al, 2012). In this article we describe the vocal repertoire in males of H. punctatus, as well as the context in which the different call types are emitted.…”