Description
This is a small tree frog with maximum SVL of 23.8 mm in males and 28.1 mm in females. The body is fairly robust and elongated with a head that is as wide as the body and wider than it is long. The snout is relatively short and truncate in dorsal view and from the profile. The eye and the nose are separated by a distance equal to the diameter of the eye. The top of the head is flat and the internarial region is depressed, the canthus is angular and the loreal region is concave. The lips are rounded. The distance between the eye and the tympanum is equal to the diameter of the tympanum. The tympanic annulus is distinct, and there is a slight supratympanic fold. The forelimbs are somewhat slender, and lack ulnar tubercles and fold. The fingers are relatively long with small, round terminal discs, and are roughly one-fourth webbed. The relative length of fingers is as follows: 1 < 2 = 4 < 3. The hind limbs are moderately slender and the toes are relatively short, with discs smaller than those on the fingers. Relative toe lengths are 1 < 2 < 3 = 5 < 4. The dorsal skin is finely granulated and the skin on the chest, belly and proximal posteroventral surfaces is more roughly granular. The posteriorly directed anal opening is located at the top of the thighs and the anal sheath is short. Tadpoles of this species have ovoid bodies in the dorsal view that are deeper than wide. The throat is convex, and the snout is bluntly rounded in the dorsal view and acutely rounded in the lateral view. The eyes are large, the spiracle is sinistral and the cloacal tube is short, conical and dextral. The caudal musculature is well developed, and tapers to a fine tip that reaches further than the posterior margin of fins. The dorsal fin originates on the body and the ventral fin is weakly crenulated. The mouth is terminal and small, and both the beak and the V-shaped lower beak are fairly heavy and finely notched (Duellman and Trueb 1989).

Dendropsophus pauiniensis adults can be differentiated from all other members of this genus, except D. timbeba by the presence of dark brown dorsal patterning. They can be differentiated from D. timbeba by its absence of blue flecks on the venter. It can be distinguished from the sympatric species D. leali by the presence of a suborbital bar and black thighs and flanks (Duellman and Trueb 1989).

In life, this frog appears pale yellow-ish tan at night. During the day, the dorsum is cinnamon brown with darker brown markings and the anterior and posterior surfaces of the thigh are black. The groin and the ventral surfaces of limbs are black with pale blue mottling, and the suborbital bar and rostral stripe are cream. The iris is pale tan with a reddish tint in the middle. Females have largely black venters and flanks, while males have brown flanks and cream venters. Males have dull yellow vocal sacs. In preservative, the dorsal surface is reddish brown with black webbing, dark brown interorbital bars, three chevrons on the body, a pair of post-sacral longitudinal marks, two transverse bars on the forearms, and five transverse bars on the shanks. Specimens have a cream rostral stripe. Both the anterior and posterior surfaces of the thighs and upper arms are black as is the ventral surface. The throat, chest and belly show cream speckling, and the groin, thighs and shanks show cream mottling (Duellman and Trueb 1989).

The coloration of Dendropsophus pauiniensis can vary a lot between individuals. The ventral surface in males is cream with back flecks, while the flanks are brown. In females, both flanks and venter are black. 76% of males examined by Duellman and Trueb had distinct chevrons on the dorsal surface, which were only found in 45% of females. 9% of males and 20% of females had indistinct dorsal patterning, and 25% of females entirely lacked dorsal patterning. The number of chevrons on those individuals who had them varied from four to seven, and some individuals had small, intermittent dorsal markings as well. The number of transverse bars on the forearm varied from one to three, though the majority of individuals had two bars. The number of bars on the shanks also varied from four to seven. While the anterior and posterior surfaces of the thighs were uniformly black on most individuals, some specimens had an orange spot on the anterior and/or posterior surface of the thighs (Duellman and Trueb 1989).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

Dendropsophus koechlini has been found in many parts of Amazonian Peru, including Departamento Loreto, the Iquitos region and Departamento Madre de Dios. It has also been observed in the flooded forests of southern Colombia and many parts of Bolivia. It is found at elevations between 200 and 280 m (Duellman and Trueb 1989, Duellman and Rodriguez 1994, Lynch 2005, Azevedo-Ramos and Angulo 2004, and Moravec et al. 2011).

Life History, Abundance, Activity, and Special Behaviors
Adults of both sexes form breeding congregations at temporary ponds in the forest after heavy rainfall. Males have been heard calling from palm fronds, branches and leaves up to 4 m above the water. The advertisement call can be identified as a high-pitched ‘creeeek’ followed by ‘eek-eek-eek.’ The primary note lasts for 0.22 to 0.40 seconds, and the secondary note is roughly 0.02 seconds long. The dominant frequency is at about 6600 hz. Amplectant pairs have been found on leaves and stems up to 1 m above the water.

Egg clutches of 300-350 eggs are deposited as a film on the surface of the water and eggs hatch within 48 hours. Tadpoles were found amid leaf litter at the bottom of temporary ponds about 50 cm deep. Tadpoles have been found in association with tadpoles of other species, such as Leptodactylus wagneri, Hamptophryne boliviana and Dendropsophus leali (Duellman and Trueb 1989).

Larva
In life, the tadpole has a brown dorsum with dark brown flanks and the ventral surface is black with white transverse stripes. The dark brown tail has creamy orange vertical bars and the iris is reddish bronze. In preservative, the dorsal surface is tan with brown flecks, and a dark brown stripe running from the snout to the eye. The ventral surface is brown with cream mottling, except for the posterior portion of the belly, which is unpigmented but has three transverse brown bars. The caudal musculature and fins are dark brown (Duellman and Trueb 1989).

Trends and Threats
This species is abundant with stable populations. It is present in well-conserved areas, such as Tambopata National Reserve, and has no major threats (Azevedo-Ramos and Angulo 2004).

Comments
The species is named for Jose E. Koechlin von Stein, owner of the Albergue Cuzco Amazonico (Duellman and Trueb 1989).

This species is synonymous with Hyla koechlini (Faivovich et al. 2005) and Dendropsophus koechlini (Melo-Sampaio 2023) in which he confirms it is a junior synonym of D. pauiniensis.

References

Aparicio, J., Guerrero-Reinhard, M., and Calderon, G. (2011). ''Anuran species richness in the Departamento Pando, Bolivia.'' Tropical vertebrates in a changing world. Schuchmann, K.L., eds., Museum Alexander König, Bonn, Germany, 47-57.

Azevedo-Ramos, C., Angulo, A. (2004). Dendropsophus koechlini. 2012 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 09 April 2013.

Duellman, W.E., and Trueb, L. (1989). ''Two New Treefrogs of the Hyla parviceps Group from the Amazon Basin in Southern Peru.'' Herpetologica, 45(1), 1-10.

Faivovich, J., Haddad, C. F. B., Garcia, P. C. A., Frost, D. R., Campbell, J. A., Wheeler, W. C. (2005). ''Systematic review of the frog family Hylidae, with special reference to Hylinae: phylogenetic analysis and taxonomic revision.'' Bulletin of the American Museum of Natural History, (294), 1-240. [link]

Lynch, J. D. (2005). ''Discovery of the richest frog fauna in the world—an exploration of the forests to the north of Leticia.'' Revista de la Academia Colombiana de Ciencias, 29, 581-588.

Melo-Sampaio PR (2023). "On the taxonomic status of Dendropsophus koechlini (Duellman & Trueb, 1989)." Journal of Vertebrate Biology, 72(23022), 1-11. [link]

Rodríguez, L. O., and Duellman, W. E. (1994). Guide to the Frogs of the Iquitos region, Amazonian Perú. The University of Kansas, Lawrence, Kansas.

Species Account Citation: AmphibiaWeb 2023 Dendropsophus pauiniensis <https://amphibiaweb.org/species/899> University of California, Berkeley, CA, USA. Accessed Jan 22, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Jan 2025.

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