Description
Pristimantis samaniegoi is a small frog with a snout-vent length range of 17.1 - 20.7 mm in adult females and 14.7 - 16.9 mm in adult males. The head is narrower than its body and is wider than it is long. The species has a short snout that is rounded in both dorsal view and in profile. The nostrils are not protuberant, and the lips are not flared. The canthus rostralis is slightly concave in dorsal view but rounded in profile. The loreal region is flat. The eye diameter is greater than the eye to nostril distance. The cranial crests are absent, and the upper eyelid has several small tubercles. The tympanic annulus and membrane are absent. There is one rounded postrictal tubercle present. The skin on the dorsum is tuberculate, and the skin on the throat, chest, belly, and ventral surfaces of the thighs are areolate. The relative finger length is I < II < IV < III. The finger discs are slightly expanded and rounded. The species’ hindlimbs are short. The discs on the toes are also slightly expanded and rounded and lack lateral fringes. The toes have ventral pads defined by circumferential grooves. The relative toe length is I < II < III < V < IV. Toe V is only slightly longer than Toe III, and webbing basal is present (Székely et al. 2020).

DIAGNOSIS:

In the Pristimantis orestes group, only three species, P. samaniegoi, P. matildae, and P. colodactylus, lack a tympanic annulus and tympanic membrane. However, P. samaniegoi can be distinguished from P. matildae and P. colodactylus by the former having following characteristics: thoracic and discoidal folds, supratympanic fold, several small tubercles on the upper eyelid, Toe V is slightly longer than Toe III, and males have a large vocal sac below the throat and vocal slits. From other species, P. samaniegoi does not have spots on the axilla, groin, limbs, and venter like P. quintanai, P. saturninoi, and P. simonbolivari. Additionally, P. samaniegoi can be distinguished from P. tiktik by the former's finely tuberculated dorsum and dark gray venter without reticulum. None of the other similar species have dark coloration with white spots as seen in the females of P. samaniegoi. The species’ call is most similar to P. tiktik’s, but P. samaniegoi’s call is doubled-noted, has a longer inter-call and inter-note interval, a lower call rate, and a lower dominant and 90% bandwidth frequency (Székely et al. 2020).

COLORATION:

In life, the species is dark brown with irregular yellowish-white spots on the dorsum, flanks, and dorsal surfaces of hind limbs and arms. The venter and throat are gray and have no spots. It has whitish-gray irises with a dark metallic brown streak and fine black reticulations. Males never have white spots like females. The supratympanic fold is black in both females and males. In preservative, the color of the dorsum, flanks, and dorsal surfaces of the hind limbs turned dark gray. The spots became light gray. The dorsal surfaces of the arms, venter, and throat also turned light gray (Székely et al. 2020).

VARIATION:

The species has evident sexual dimorphism in both size and coloration. Females are larger than the males. Additionally, females are dark brown with white, irregular spots and a dark gray venter while males have lighter colored dorsums, from light brown to reddish brown, with light green and gray flanks. Males also have pinkish-white to light gray venters(Székely et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Ecuador

View distribution map in BerkeleyMapper.

The species is found at the Cajanuma entrance to the Parque Nacional Podocarpus and around 13 km north in Abra de Zamora in southern Ecuador. The species is found in evergreen upper montane forest, subpáramo, and shrub páramo ecosystems at an altitude range between 2560 and 3300 m a.s.l. (Székely et al. 2020).

Life History, Abundance, Activity, and Special Behaviors
Pristimantis samaniegoi is a commonly found species. All individuals were found during the night, close to the ground at about 5 - 20 cm above the ground. Individuals were found at the base of grassy vegetation, shrub leaves, and moss beds under shrubs. The species is hard to find because individuals are hidden at the base of shrubs or inside moss beds and grassy vegetation (Székely et al. 2020).

The male’s advertisement call is commonly heard year-round but more frequent on rainy nights. Females were found in direct proximity to calling males (Székely et al. 2020).

Pristimantis samaniegoi’s advertisement call consists of repeated clicking for long periods of time. The call is similar to P. tiktik and P. vidua. The calls have two short, single-pulsed notes. The duration of the call series is unknown because they can call continuously, However, individual call durations lasted 0.017 - 0.040 s with an inter-call interval of 0.234 - 0.362 s resulting in a call rate of 185.9 calls/min. The short notes last 0.002 - 0.006 s while the long notes last 0.003 - 0.010 s and have an inter-note duration of 0.006 - 0.028s. The dominant frequency is 2842.4 - 3359.2 Hz and has 3 - 4 harmonics (Székely et al. 2020).

Trends and Threats
Pristimantis samaniegoi should be categorized as “Near Threatened” based on IUCN Red List Criteria. The species is abundant and does not currently face major threats due to its location in the Parque Nacional Podocarpus, a nationally protected area (Székely et al. 2020).

Comments

PHYLOGENETIC RELATIONSHIPS:

Pristimantis samaniegoi is in the Pristimantis orestes species group based on Maximum Likelihood and Bayesian analyses of two mitochondrial genes (12S and 16S) and one nuclear gene (RAG-1) from 123 individuals of 56 species from Ecuador and Peru. Those analyses also indicate that P. samaniegoi is most closely related to the clade composed of P. quintanai and an undescribed species. However, this relationship is not strongly supported (Székely et al. 2020).

ETYMOLOGY:

The species is named after Dr. Gustavo Samaniego Rodríguez, who was important to the conservation efforts of biodiversity in southern Ecuador. He donated part of his land to create the administrative and interpretation center of the Parque Nacional Podocarpus, an important biodiversity site in Ecuador (Székely et al. 2020).

References

Székely P., Eguiguren J. S., Ordóñez-Delgado L., Armijos-Ojeda D., Székely D. (2020). “Fifty years after: A taxonomic revision of the amphibian species from the Ecuadorian biodiversity hotspot Abra de Zamora, with description of two new Pristimantis species.” PLOS ONE, 15(9), e0238306. [link]

Species Account Citation: AmphibiaWeb 2022 Pristimantis samaniegoi: Samaniego’s Rain Frog <https://amphibiaweb.org/species/9256> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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