Description
The medium-sized frog, Pristimantis rupicola, has a snout-vent range of between 18.1 – 28.2 mm, with the snout being described as either rounded or abbreviated when viewed in profile. The head lacks cresting and is approximately as wide as it is long, and the upper eyelid features sparse small granules. The tympanic membrane is visibly distinct and mostly symmetrical. The skin on the throat has a smooth appearance while the surface of the dorsum appears granular and the belly is areolate. The extremities are lengthy and attenuated. On the forelimbs, there is a line of ulnar tubercles as well as clefted and flat palmar tubercles. The fingers have large tips, have subarticular tubercles, do not have lateral fringes, and have a relative length of III > IV > II ≈ I. The dorsal region of the hind limbs has a smooth appearance. The heels lack tubercles, and the toes lack webbing. The relative lengths of toes are toe IV > V > III > II > I (Taucce et al. 2020).

DIAGNOSIS:

Pristimantis rupicola can be distinguished from other similar species based on a few key morphological traits. The frog can be differentiated from species in the P. conspicillatus group, which includes its most closely related species, P. gaigei, because P. rupicola has a dorsal surface that is similar in appearance to granite rock and it has a varying amplitude advertisement call. Pristimantis rupicola can also be differentiated from P. gaigei in that the former has a rounded snout, a granular dorsal surface, and a smooth ventral surface. Additionally, male P. rupicola frogs can be further differentiated from P. gaigei due to their possession of vocal slits (Taucce et al. 2020).

COLORATION:

In life, the skin of the dorsum most often appears in a range from light brown to yellowish-brown, interrupted by blackish-brown marks, which resemble that of a granite rock surface. Additionally, P. rupicola is found with skin in varying shades of rust. With respect to the ventral surfaces, it often appears as a pinkish-white shade that features dark spots. The spotting pattern is often concentrated on the extremities. Pristimantis rupicola does not have dorsal stripes, and the eyes of most observed specimens appear bluish or yellowish (Taucce et al. 2020).

VARIATION:

Most adult female specimens of P. rupicola had a greater size than the males, and males possess vocal slits and nuptial pads. In terms of variation between observed specimens, some snouts appeared more prominently truncated in dorsal view, and Finger I is either slightly smaller, equal to, or slightly larger than Finger II. Additionally, some specimens exhibited a pattern of dark brown spots in the shape of a W on the dorsum (Taucce et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

Pristimantis rupicola is known from the highlands of the Chapada Diamantina National Park within the state of Bahia in Northeastern Brazil. In the highlands, the frog is often found on rocky surfaces or shrub vegetation in gallery forests at an elevation between 870 to 1,800 meters (Taucce et al. 2020).

Life History, Abundance, Activity, and Special Behaviors
As hinted in the name, P. rupicola spends much of its lifetime navigating rock crevices. The frog also frequents gallery forests or shrub vegetation at waterfalls. These locations are where most of the males’ nocturnal calls take place, which can even be made in choruses (Taucce et al. 2020).

The advertisement calls of P. rupicola are relatively short (0.011 – 0.086 s) and composed of single notes that are either pulsed or not. When notes are pulsed there can be 2 - 23 pulses that last 0.002 - 0.015 s each at a rate of 166.7 - 500.0 pulse/s. Intercall intervals ranged from 1.74 - 5.30 s. The calls show amplitude modulation with energy decreasing throughout the length of the call and a dominant frequency from 2.41 to 3.49 kHz. Two additional, but less emphasized frequency peaks are also present with the second peak ranging from 4.0 to 6.9 kHz and the third peak ranging from 8.09 to 10.47 kHz (Taucce et al. 2020).

Trends and Threats
Pristimantis rupicola spends most of its lifetime dwelling on rocks and can be most often found in the specific region of Campo Rupestre within the Chapada Diamantina. Due to the specificity of its habitat, it often experiences threats due to uncontrolled land use and occupation, fire, cattle breeding, and tourism that is not properly regulated (Taucce et al. 2020). However, as of 2022, P. rupicola has not yet been assessed by the IUCN Red List.

Comments

PHYLOGENETIC RELATIONSHIPS:

The genus, Pristimantis, is known to be highly diverse and therefore likely to contain cryptic species. To determine genetic relationships, a phylogenetic tree was created based on Bayesian Inference and Maximum Likelihood analysis of the 16S ribosomal RNA gene. In that tree, P. gaigei and P. rupicola formed a clade, suggesting that they are sister taxa and are most closely related to each other (Taucce et al. 2020).

ETYMOLOGY

The species epithet is derived from the word “rupes”, which is Latin for “rocks” in combination with the suffix “-cola”, meaning “dweller”. Therefore, put together, the species epithet, “rupicola” signifies the frog as a “rock dweller” (Taucce et al. 2020).

OTHER INTERESTING INFORMATION:

A suggested vernacular name for P. rupicola is “Rock-Dwelling Robber Frog” (Taucce et al. 2020).

References

Taucce, P. P. G., Nascimento J. S., Trevisan C. C., Leite, F. S. F., Santana, D. J., Haddad, C. F. B., Napoli, M. F. (2020). "A new rupicolous species of the Pristimantis conspicillatus group (Anura: Brachycephaloidea: Craugastoridae) from Central Bahia, Brazil." Journal of Herpetology, 54(2), 245-257. [link]

Species Account Citation: AmphibiaWeb 2022 Pristimantis rupicola: Rock-Dwelling Robber Frog <https://amphibiaweb.org/species/9190> University of California, Berkeley, CA, USA. Accessed Dec 2, 2022.

Citation: AmphibiaWeb. 2022. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 2 Dec 2022.

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