Description
Pristimantis pictus is a frog with an average snout-vent length of 33.84 mm for females and 32.95 mm for males. The head is longer than it is wide, and a little more of a third of the snout-vent length. The snout is long, slightly less than half of the head length, and slightly tapers in their dorsal view while protruding in the lateral view. From the dorsal view, the canthus rostralis is slightly concave and the loreal region is flat. The distance from eye to nose is about the same as the horizontal diameter of the eye. The eye has an elliptical pupil. The tympanic membrane is about 41% of the eye length, with a prominent rounded and translucent tympanic annulus. The supratympanic fold is prominent but does not make contact with the eyelid. Cranial crests are absent. The lateral region of the dorsum is shagreen with tubercles, but the dorsolateral fold varies from present to absent. The belly texture is smooth in the center but granular laterally. Males have a vocal sac. The hands are relatively small, only about 28.7% of the snout-vent length, with a semi-divided, heart-shaped external metacarpal tubercle and a large internal palmar tubercle. They have one supernumerary tubercle present at the base of all fingers that is almost the same size as the subarticular tubercles. The fingers have lateral fringes and a relative finger length of II < IV < I < III. There is one prominent, conical subarticular tubercle on fingers I and II, two prominent, conical subarticular tubercles on fingers III and IV. The discs on fingers III and V are wider than I and II. They have long legs, with the tibia being about 59.1% of the snout-vent length. The foot has a well-developed, oval inner metatarsal tubercle, a much smaller external metatarsal tubercle, and a long inner tarsal fold. There are no supernumerary tubercles on the planter. The relative length of the toes are I < II < V < IV and there is one subarticular tubercle on the toes I and II, two on the toes III and V, and three on toe IV. Finally, there is basal webbing and lateral fringes present on all toes (de Olivera et al. 2020).

DIAGNOSIS:

One can distinguish P. pictus from P. giorgii because yellow spots are present in P. pictus, but not P. giorgii. The vocalization of the P. pictus is composed of 4 to 5 notes, unlike the P. latro whose vocalization is composed of 7 notes. These characters, in addition to a laterally granular belly and webbing in toes in P. pictus differentiate it from P. valarsi, which has an absence of yellow spots, an eight note call, a smooth belly, and no toe webbing. Lastly, P. samaipatae has an immaculate white belly, whereas P. pictus has a white belly with randomly scattered black dots (de Olivera et al. 2020).

COLORATION:

In life, the dorsum of P. pictus is reddish in color with yellow dots adorning the flanks to form a separation between the off-white lateral venter. The front and back limbs show dark brown bars, and the posterior thigh surface is dotted with yellow spots on a brown background. These yellow spots reach the groin area that extends across the lateral half of its body. The belly is white and has tiny black dots scattered about randomly. A weak canthal stripe is present, a labial bar, and the iris is golden at the top and bottom and mostly red in the anterior and the posterior region. In preservative, the dorsum becomes brown and the bands on the snout fades. The yellow posterior spots on the thighs become white (de Olivera et al. 2020).

VARIATION:

On average, females are larger than males and there is some variation in skin texture and coloration. Generally, the intensity of the shagreen dorsal texture varies among individuals, and the belly texture is predominantly smooth in the center and granular laterally. However, some individuals have completely smooth bellies as opposed to textured, and some present distinct patterns. Lateral dorsal folds are common, but can be absent. Some individuals have “heavily stained” venters and the dorsum may have transverse and interorbital bars or other distinct patterns (de Olivera et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

Pristimantis pictus was found in Brazil in the municipalities of Cotriguacu, Novo Mundo, Tabapora, Paranaita, and Sinop in Mato Grosso state and Jacareacanga in Para State. They reside at the edges of preserved forests, near pastures (de Olivera et al. 2020).

Life History, Abundance, Activity, and Special Behaviors
Pristimantis pictus has a vocalization consisting of four to five notes that last 0.017 - 0.033 s and has 3 - 12 pulses. The total call length ranges from 0.216 - 0.302 s and has a fundamental frequency of 1405.63 - 1914.71 Hz, and a dominant frequency of 2487.42 - 3272.24 Hz (de Olivera et al. 2020).

Comments

PHYLOGENETIC RELATIONSHIPS:

ETYMOLOGY:

The species epithet, “pictus” is Latin and means “painted or stained”. This is in reference to the yellow spots they are adorned with across its body (de Olivera et al. 2020).

References

de Oliveira, E. A., da Silva, L. A., Silva, E. A. P., Guimarães, K. L. A., Penhacek, M., Martínez, J. G., Ribeiro Rodrigues, L. R., Santana, D. J., Hernández-Ruz, E. J. (2020). “Four new species of Pristimantis Jiménez de la Espada, 1870 (Anura: Craugastoridae) in the eastern Amazon.” PLoS ONE, 15(11), e0243182 [link]

Species Account Citation: AmphibiaWeb 2023 Pristimantis pictus <https://amphibiaweb.org/species/9151> University of California, Berkeley, CA, USA. Accessed Apr 24, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 24 Apr 2024.

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