Structural diversity of nuptial pads in Phyllomedusinae (Amphibia: Anura: Hylidae)

Abstract

We studied the morphological variation of the nuptial pads using light microscopy and scanning electron microscopy (SEM) in 26 species of phyllomedusines (Anura: Hylidae), representing the five currently recognized genera. All phyllomedusines have single nuptial pads with dark colored epidermal projections (EPs). Spine-shaped EPs occur in Cruziohyla calcarifer, Phrynomedusa appendiculata and in one species of Phasmahyla. The other species have roundish EPs. The density of the EPs on the pad is variable. Species in the Phyllomedusa hypochondrialis Group have EPs with a density that varies between 764 ± 58/mm(2) and 923 ± 160/mm(2). In all other studied species (including the Phyllomedusa burmeisteri and Phyllomedusa perinesos groups, Phyllomedusa camba, Phyllomedusa boliviana, Phyllomedusa sauvagii, Phyllomedusa bicolor, and Phyllomedusa tomopterna) the density of EPs varies between 108 ± 20/mm(2) and 552 ± 97/mm(2). Pores were observed with SEM in C. calcarifer, Agalychnis lemur, Agalychnis moreletii, but its presence is confirmed through histological sections on several other species. Its visibility using SEM seems to be related with the level of separation between adjacent EPs. The pores in the four studied species of Agalychnis are shown with SEM and histological sections to have a characteristic epidermal rim, that is absent in the otherphyllomedusines. Unlike most previous reports on breeding glands, those of phyllomedusines are alcian blue positive, indicating the presence of acidic mucosubstances on its secretions.

Systematics of Ecnomiohyla tuberculosa with the description of a new species and comments on the taxonomy of Trachycephalus typhonius (Anura, Hylidae)

“…material 2. Character definitions follow Duellman (1970) and Luna et al (2012) for nuptial excrescences. Notation for hand and foot webbing is based on Myers and Duellman (1982).…”

No sexual dimorphism in limb muscles of a frog not engaging in amplexus

“…However, amplexus does not occur in F. taihangnicus and sexual dimorphism in limb muscle size was absent. Additionally, in many anuran species which exhibit amplexus, males develop a variety of elaborate structures such as nuptial pads and glands in the ventral skin which help the amplexing male to tightly grip the female (Duellman & Trueb, 1994;Luna et al, 2012). However, these traits are absent in species without amplexus (Wells, 1977), including F. taihangnicus studied here .…”

Froghood: Postmetamorphic development of the rock river frog Thoropa miliaris (Spix, 1824) (Anura, Cycloramphidae)

“…Laboratory studies have demonstrated that hormonal stimulation is involved in the development of these structures (Iwasawa & Kobayashi, 1974;Kao, Alexander, Yang, & Yu, 1994;Zimmer & Dent, 1981). Another line of investigation aimed to describe the excrescences morphologically (e.g., Kurabuchi, 1993;Kyriakopoulou-Sklavounou et al, 2012;Luna et al, 2012). However, none of these studies correlated development and age.…”

“…Males of Thoropa, as those of several other species of anurans, develop a nuptial excrescences on parts of the fingers (Bokermann, 1965). These excrescences are keratinized structures derived from the epidermis and vary in morphology among species (e.g., Cuevas & Formas, 2001;Kyriakopoulou-Sklavounou, Papaevangelou, & Kladisios, 2012;Luna, Taboada, Baêta, & Faivovich, 2012). Nuptial excrescences may be used by some males during territorial disputes and aggressive behaviour (Cocroft & Heyer, 1988;Shine, 1979) and are supposed to enhance males ability to hold on to the females' body during amplexus (e.g., Thomas, Tsang, & Licht, 1993).…”