Description
Brachycephalus fuscolineatus is a robust-bodied miniature frog with an adult snout to vent length range of 9.7 - 12.4 mm. The head is slightly wider than long. The snout is short, about the same length as the diameter of the eye. The nostrils do not protrude and are directed anterolaterally. The canthus rostralis is indistinct and the loreal region is slightly concave. The lips are almost sigmoid. The eyes slightly protrude from the head when looking at the species from dorsal or lateral perspectives. The tympanum is not distinct. The arms are slim and the hands do not have metacarpal tubercles. The digits are reduced, with the first and fourth fingers being vestigial and the relative finger lengths being IV < I < II < II. Fingers I and II are somewhat rounded while finger III is pointed. The fingers lack subarticular tubercles. The hind limbs are short and robust and the feet lack an inner metatarsal tubercle but have a large, oval, outer metatarsal tubercle. On the feet, the first and fifth toes appear rudimentary and the relative toe lengths are II < III < IV. Webbing, subarticular tubercles, and toe pads are absent. The skin of this frog is granular with only the chin and forelimbs being smooth. There are large granular warts on the dorsum, legs, and both sides of the belly. There are small glandular warts near the vertebral column, on the head, and on the arms. There are no dermal co-ossifications (Ribeiro et al. 2015).

Brachycephalus fuscolineatus is a member of the B. pernix species group. For a diagnosis please see Ribeiro et al. 2015.

In life, the species is predominantly yellow to orange and has a dark band with indistinct edges that runs vertically along the spine of the frog from snout to the cloacal opening. This dark coloration varies in width and coverage between individuals, and may run into the limbs or irregularly spot throughout the trunk and head. The dark band may appear as black, brown, gray, or dark green in some individuals. The eyes are fully black. In preservative, the stripe does not change color but the dorsal and lateral surfaces become light gray while the ventral surface becomes pale cream (Ribeiro et al. 2015).

VARIATION:

Between individuals, the dark dorsal stripe varies in width and in the shape (Ribeiro et al. 2015).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

Brachycephalus fuscolineatus’ range is restricted to a small high elevation range (525 – 790 m) in the Brazilian Atlantic Forest; specifically in Morro do Baú and Morro Braço da Onça, State of Santa Catarina, Brazil. This species is a microendemic, having a range of 23.63 ha. Individuals have been found hidden in the leaf letter of primary montane forest at both sites of occupancy. They are found at least 15 m from forest edges (Ribeiro et al. 2015, Bornschein et al. 2019 - Check).

Life History, Abundance, Activity, and Special Behaviors
Brachycephalus fuscolineatus can be found, hidden in leaf litter where some can be found calling from (Ribeiro et al. 2015).

Little is known about B. fuscolineatus, however, the general behavior of Brachycephalus species are that they are terrestrial, diurnal, restricted to mountain tops, and found in leaf litter on dense forest floors (Pombal 1994).

Trends and Threats
As of 2022, the IUCN Red List has not yet assessed this species; however, Bornschein et al. (2019 - Diversity) evaluated Brachycephalus species using the IUCN Red List criteria with newer locality information and concluded this species should be listed as Critically Endangered (criteria B1ab(i,iii)+2ab(ii,iii)).

The main threats to B. fuscolineatus populations is loss of their already restricted habitat and the use of herbicides. The eastern mountains of Santa Catarina, where this species is found, is under great ecological pressure for the installment of cell phone towers and power plants. Construction of these infrastructures and roads to the sites will also contribute to edge effects such as a decrease in the humidity of the forest, which the frogs depend on to survive. Another major threat to this species is the inevitable expansion of palm and eucalyptus plantations that are taking over much of Brazil’s rainforest. These plantations not only destroy habitat, but also introduce large amounts of herbicides into the habitat of B. fuscolineatus and has unknown consequences on their health. Tourism, and the waste from tourism, may also have a negative impact on the species (Bornschein et al. 2019 - Check, Diversity). Because of the limited range and threats to the species Bornschein et al. (2019 - Diversity) recommend a “Critically Endangered” IUCN Red List threat status.

Possible reasons for amphibian decline

General habitat alteration and loss
Subtle changes to necessary specialized habitat
Local pesticides, fertilizers, and pollutants

Comments

PHYLOGENETIC RELATIONSHIPS:

Bayesian Inference of 16S mtDNA found that B. fuscolineatus forms a polytomy with B. albolineatus and B. mirissiums. The next most closely related species is B. boticario (Pie et al. 2018).

ETYMOLOGY

The species epithet, “fuscolineatus” is from the Latin, “fuscus”, which means “dark-skinned” and “lineatus”, which means “to make straight like a line.” The name refers to the dark stripe that is present across the back of the species (Ribeiro et al. 2015).

References

Bornschein M.R., Teixeira L., Ribeiro L.F. (2019). “New record of Brachycephalus fuscolineatus Pie, Bornschein, Firkowski, Belmonte-Lopes & Ribeiro, 2015 (Anura: Brachycephalidae) from Santa Catarina state, Brazil.” Check List 15(3), 379–385. [link]

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]

Pie, M., Ribeiro, L., Confetti, A., Nadaline, M., and Bornschein, M. (2018). ''A new species of Brachycephalus (Anura: Brachycephalidae) from southern Brazil.'' PeerJ, 6, e5683.

Pombal, J. P. Jr., Sazima, I., and Haddad, C. F. B. (1994). "Breeding behavior of the pumpkin toadlet, Brachycephalus ephippium (Brachycephalidae)." Journal of Herpetology, 28, 516-519. [link]

Ribeiro, L. F., Bornschein, M. R., Belmonte-Lopes, R., Firkowski, C. R., Morato, S. A., Pie, M. R. (2015). “Seven new microendemic species of Brachycephalus (Anura: Brachycephalidae) from southern Brazil.” PeerJ 3, e1011. [link]

Species Account Citation: AmphibiaWeb 2022 Brachycephalus fuscolineatus <https://amphibiaweb.org/species/8340> University of California, Berkeley, CA, USA. Accessed Nov 12, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 12 Nov 2024.

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