Günther, A. C. L. G. (1869) "1868". First account of species of tailless batrachians added to the collection of the British Museum. Proceedings of the Zoological Society of London 1868: 478–490.

	hear Fonozoo call

Description

Dendropsophus triangulum has a snout vent length range of 28.6 - 34.4 mm in males and 37.5 - 41.9 mm in females. There’s an axillary membrane that goes down the arm and reaches halfway to the elbow. They have basal webbing on their fingers and webbing on their toes. They have a single palmar tubercle (Caminer et al. 2017).

Dendropsophus triangulum is most similar to D. arndti and D. leucophyllatus, however it can be distinguished by the former’s brown hourglass-shaped or triangular sacral mark. Its white or yellow rounded sacral mark can also be differentiated from the rounded mark with irregular edges in D. arndti and the leaf-shaped mark in D. leucophyllatus. Dendropsophus triangulum can also be differentiated from D. reticulatus by its advertisement call and from most other similar Dendropsophus frogs by its larger size. Its wide dorsolateral bands also differentiate it from many other Dendropsophus species (Caminer et al. 2017).

In life, the dorsal coloration is white or bright yellow with a brown hourglass-shaped or triangular sacral mark. The dorsal surfaces of the limbs are brown and these surfaces have white or bright yellow long, ovoid bands or rounded spots. The webbing and ventral surfaces have a pale orange to yellowish orange coloration. These areas as well as the anterior and posterior surfaces of the thighs are yellowish orange at night and become pale orange in the day. The iris is a dull bronze to orange bronze (Caminer et al. 2017).

There is sexual size dimorphism in this species, with the females being larger, as well as individual color variation. The coloration of the ventral surfaces, webbing, and anterior and posterior surfaces of the thighs vary from a yellowish orange to a pale orange depending on if it’s day or night. The dorsal coloration varies from a brown to a dark brown. The sacral mark can either be in an hourglass shape or a triangular shape, appearing as if it is half of the hourglass. The number of white or bright yellow rounded spots on the limbs varies from one to two on the forearms and one to three on the shanks. Some individuals have a reticulated color pattern (Caminer et al. 2017).

There may be seven color morphs identified for this species (Duellman 1974). Since the color morphs were identified, another species with an overlapping range, D. reticulatus, was described with the same color morphs. So whether these color morphs still refer to D. triangulum is unclear. Those morphs are:

1. No dorsal markings
2. One dark spot in the occipital region
3. One dark spot in the occipital region and one dark spot in the middle of the dorsum
4. A long ovoid dark spot from the occipital region to the middle of the dorsum
5. Three dark spots on the dorsum in a line starting from the occipital region. The distance between the first two spots is closer than in other color morphs.
6. Middorsal spots from the occiput to the rump
7. Spots scattered over the entire dorsum

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Bolivia, Brazil, Colombia, Ecuador, Peru

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (1 records).

Dendropsophus triangulum is found in the Amazon basin of Ecuador, Peru, and Brazil. It can be found in elevations of 34 - 387 meters above sea level. In Ecuador, it is most often found in Amazonian Lowland Evergreen Forest, Floodplain Lowland Forest, and Lowland Forest of Palms. In these different types of forests, it can be found in pools, lakes, and swamps. In Peru and Brazil, the vegetation types that it’s found in include Napo Moist Forest, Southwest Amazon Moist Forest, and Uatuma-Trombeta Moist Forests (Caminer et al. 2017).

Life History, Abundance, Activity, and Special Behaviors

This species has two types of calls: an advertisement call and an aggressive call. The advertisement call has one pulsed, trill note with an average duration of 0.15 s and 13 - 21 pulses/note followed by one to three secondary notes that have an average duration of 0.034 s and 3 - 5 pulses per note. This call has an average duration of 0.26 s with an average dominant frequency of 2456.43 Hz, 0.13 s mean rise time, and a mean frequency bandwidth of 494 Hz (Caminer et al. 2017).

The aggressive call has 4 - 5 pulsed notes with an average interval of 0.027 s between notes. The call has an average duration of 0.24 s, an average dominant frequency of 2411.74 Hz, a mean rise time of 0.14 s, and a mean frequency bandwidth of 427.4 Hz (Caminer et al. 2017).

Trends and Threats

Dendropsophus triangulum is a “Least Concern” species because their range has large overlaps with protected areas and only a small percent of its total range has been degraded by human activities (Caminer et al. 2017).

Comments

Based on a 2017 Maximum Likelihood and Bayesian analysis of mtDNA and nucDNA, D. triangulum was found to be sister to three unconfirmed candidate species in the genus. The relationship between these species was unclear due to lack of data (Caminer et al. 2017). In a 2021 total evidence analysis of the Dendropsophus genus using previously published data as well as new samples of 12S and 16S mtDNA and nucDNA concluded that D. triangulum is sister to D. reticulatus, however the researchers didn’t include D. leucophyllatus, D. arndti, and D. vraemi in their study (Orrico et al. 2021). The discrepancies between these two analyses leave the phylogenetic relationships of D. triangulum unclear.

References

Caminer, M. A., Milá, B., Jansen, M., Fouquet, A., Venegas, P. J., Chávez, G., Lougheed, S. C. and Ron, S. R. (2017). Systematics of the Dendropsophus leucophyllatus species complex (Anura: Hylidae): Cryptic diversity and the description of two new species. PLoS (Public Library of Science) One 12(3), e0171785 [link]

Duellman, W. E. (1974). A reassessment of the taxonomic status of some neotropical hylid frogs. Occasional Papers of the Museum of Natural History, University of Kansas 27: 1–27. [link]

Orrico, V. G. D., Grant, T., Faivovich, J., Rivera-Correa, M., Rada, M. A., Lyra, M. L., Cassini, C. S., Valdujo, P. H., Schargel, W. E., Machado, D. J., Wheeler, W. C., Barrio-Amorós, C., Loebmann, D., Moravec, J., Zina, J., Solé, M., Sturaro, M. J., Peloso, P. L. V., Suarez, P., and Haddad, C. F. B. (2020). The phylogeny of Dendropsophini (Anura: Hylidae: Hylinae). Cladistics, 37(1): 73 - 105. [link]

Species Account Citation: AmphibiaWeb 2023 Dendropsophus triangulum <https://amphibiaweb.org/species/979> University of California, Berkeley, CA, USA. Accessed Apr 19, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 19 Apr 2024.

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