Description
This small frog, like other diminutive amphibians, has morphological reductions and losses in digits and other osteological elements (see Giaretta and Sawaya 1998 for figures).

In life, this small frog is brownish yellow or palebrown on the dorsum. The dorsal surface of the thigh may show a pale pink pattern. 40% of preserved specimens display narrow stripes that form a dark X on the dorsum. Some individuals have large symmetrically paired dark spots on the dorsum and/or sacrum region. Some have the dorsum of the limbs crossed with a gray stripe. A narrow vertebral stripe may be present, and in some specimens, lateral coloration is darker than dorsum. Ventral surfaces are pale gray with many brown spots. Belly has many intersperced glandular areas on a uniformly dark with white spotted background. Its close relative, B. didactylus, differs by having its glands concentrated onto one belly area and thus creating a black spot. The head is wider than it is long, and in dorsal view the snout is rounded. Nostrils closer to tip of snout than to the eyes. Tympanum indistinct but visible. Anterior border of nostrils and inferior border of eys are grooved. First and fourth fingers vestigial, third larger than second. First toe is absent and the second is larger than fith and smaller than third. Skin is smooth or slightly granular on upper eyelid and nostril. Osterodermal plate on the body is absent (found in the sister genus Brachycephalus). The presence of a functional 5th toe in this species is unique within not only this genus, but also in other diminutive frogs of the genus Brachycephalus and Euparkarella (Lynch 1971).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

Known from 3 localities in the municipality of Ubatuba, Brazil: Picinguaba, Fazenda Capricornio, and Corcogado.

Life History, Abundance, Activity, and Special Behaviors
Males have an external vocal sac that extends from the gular region to midbelly. Females were frequently encountered with a bulk on one side of the body due to the presence of a single maturing oocyte.

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities

Comments
Originally described as Psyllophryne hermogenesi as one of two species belonging to the genus, Kaplan (2002) questioned the genus based on morphological analysis of characters and their origin, resulting in synonomizing with .

IUCN Red List's assessment of this species is Least Concern; however, Bornschein et al (2019) analysed the Brachycephalus species using the IUCN Red List criteria with newer information and concluded this species as Vulnerable, based on its limited known range and ongoing habitat loss.

References

Bornschein, M. R., Pie, M. R., Teixeira, L. (2019). "Conservation status of Brachycephalus toadlets (Anura: Brachycephalidae) from the Brazilian Atlantic rainforest.” Diversity, 11(150), 1-29. doi: 10.3390/d11090150 [link]

Giaretta, A. A., and Sawaya, R. J. (1998). ''Second species of Psyllophryne (Anura: Brachycephalidae).'' Copeia, 1998(4), 985-987.

Kaplan, M (2002). "Histology of the anteroventral part of the breast-shoulder apparatus of Brachycephalus ephippium (Brachycephalidae) with comments on the validity of the genus Psyllophryne (Bracycephalidae)." Amphibia-Reptilia, 23, 225–227.

Lynch, J. D. (1971). ''Evolutionary relationship, osteology, and zoogeography of leptodactyloid frogs.'' Occasional Papers of the Museum of Natural History, University of Kansas, 53, 1-238.

Species Account Citation: AmphibiaWeb 2022 Brachycephalus hermogenesi <https://amphibiaweb.org/species/5514> University of California, Berkeley, CA, USA. Accessed Nov 22, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Nov 2024.

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