Description
Boana pulchella is a moderately sized frog with a snout-vent length range of 35 - 45 mm for males and 40 - 50 mm for females. The head is as wide as it is long, with large, prominent eyes and horizontal pupils. The eye diameter is equal to the orbitonarial distance and is twice the diameter of the tympanum. A distinct supratympanic fold is present (Langone 1994, Achaval and Olmos 2003). This species is within the emblematically named Boana pulchella species group, which is most notably characterized by hypertrophied forelimbs, a notable tarsal fold, and prepollical spines in adult males. The small inner metatarsal tubercules are slightly visible, and there is no external metatarsal (Langone 1994). The toes have poorly developed interdigital membranes, usually following the ⅗ to ¾ webbing formula (Duellman et al. 1997). The skin is smooth dorsally, but the ventrum is granulated. Juveniles that recently metamorphosized measure 16 mm (Langone 1994).

Phylogenetic analyses reveal that Boana pulchella is closely related to Boana cordobae, but the latter tend to be slightly larger (53 mm) and have a strong dorsal speckled pattern rather than the loose marbling associated with some B. pulchella types (Baraquet et al. 2018). Boana pulchella may also be confused for Dendropsophus sanborni and Scinax uruguaya. Dendropsophus sanborni can be distinguished by its smaller size (15 - 20 mm), its brown-yellow dorsal coloration, and well-developed interdigital membranes in the posterior limbs. Scinax uruguaya can be distinguished by its small size (22 - 28 mm), dorsal-cephalic yellow coloration, and dorsal granular skin (Achaval and Olmos 2003).

In life, much variation exists in coloration. Dorsal color ranges from bright solid green to light brown with darker spots, accompanied by a coffee-colored lateral band that extends from the posterior edge of the eye to the groin. This band is bordered on both sides by a narrower whitish band. In green individuals, this band is replaced by a color similar to the dorsum. The ventrum is whitish. The thighs are pink with large black splotches. The vocal sac is canary yellow (Langone 1994).

There is sexual dimorphism, with males having one vocal sac and prepollical spines, as well as a smaller snout-vent length. There is also variation in coloration, as previously described, with some individuals being brown and others green (Langone 1994).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil, Uruguay

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (3 records).

Boana pulchella is distributed among subtropical South America in the countries of Argentina, Southern Brazil, Paraguay, and Uruguay. They are typically found in open habitats, ranging from forests and prairies to flooded savannas (de Amaral et al. 2021).

Life History, Abundance, Activity, and Special Behaviors
A study on age determination for the species observed a maximum lifespan of five years, with an average sexual maturity at three years of age. Body size and age were found to be positively correlated (Baraquet et al. 2021).

This species adapts its diet and metabolism to seasonal changes to efficiently remain active across a large temperature gradient (de Amaral et al. 2021).

Boana pulchella breeds in permanent bodies of water but is also found in human-altered environments such as gardens and small lakes (Baraquet et al. 2021). Boana pulchella is unique in that it is reproductively active throughout the year and adjusts its metabolism seasonally to account for environmental changes (de Amaral et al. 2021).

Males produce two-tonal calls, with a shorter first note (Grenat et al. 2023). Some have described it as a “ticlic…ticlicl…tclic” and suggest vocalizations end in an “uhmn” sound (Langone 1994). The calls range in frequency from 2.1 - 2.6 kHz (Baraquet et al. 2021).

Eggs are laid in submerged gelatinous masses, and adhered to vegetation (Achaval and Olmos 2003). Eggs are lightly pigmented and 1.5 mm in diameter (Langone 1994).

When distressed or caught, B. pulchella may excrete a strong alliaceous scent as a reflexive defense mechanism (Langone 1994).

Boana pulchella has a generalist diet consisting of arachnids, insects, and crustaceans (de Amaral et al. 2021). The species is also host to various helminths (Nematoda, Cestoda, Digenea, and Acanthocephala) (Silveira et al. 2022).

Larva
Tadpoles have an oval-shaped body with a slight constriction behind the eyes. The body is the widest at the midsection. The snout is rounded in lateral and dorsal views. The nostrils are dorsolaterally positioned, closer to the eyes than the snout, and have a fleshy medial projection. The eyes are large, positioned and directed laterally, and visible ventrally. The oral disc is anteroventral and small relative to body width, about 43 % of the body width with the disc measured folded. There is a pronounced infraangular constriction on each side of the disk. The marginal papillae are simple, have rounded tips, and are longer than wide. A dorsal gap is present that is less than a third of the width of the oral disc. The marginal papillae are in a single row except for the angular regions, where they are double. Wider, shorter lateral marginal papillae are also present. The labial tooth row formula is 2(2)/3(1) with the first anterior row being bent towards the front and the third posterior row being about half the length of the second posterior row. The upper jaw sheath has as convex, central position and is widely arched. The lower jaw sheath is V-shaped. Both jaw sheaths are well developed and serrated. There is a single sinistral spiracle that is only visible laterally as well as a visible lateral line system. The vent tube is medial and extends to the free margin of the lower fin, where it has a dextral opening (Kolenc et al. 2008). The slightly convex dorsal fin is expanded, beginning at the end of the body, with a height only slightly larger than the body’s. The beginning of the nearly straight ventral fin is hidden by the vent. The last third of the tail tapers considerably to a sharp end. The tail musculature reaches the tail tip (Langone 1994, Kolenc et al. 2008).

In life, tadpoles are dark brown with gold accents. The fins are pigmented brown as well (Langone 1994). In preservative, the tadpole body is yellow-brown dorsally with dark brown markings on the head and inner margins of nostrils. Small dark spots are spread through the dorsal head and body. Laterally the coloration is dark brown, and the venter is translucent. The caudal musculature is yellow-tan colored with irregular dark regions that can create a dark/light transversal pattern, dorsally. The fins are opalescent with dark blotches (Kolenc et al. 2008).

There is variation in the oral disc and body with. The tooth row formula have been recoreded as 2(2)/3, 2(1,2)/3(1), 2(2)/3(2), or 2(2)/4(1) formula. Labial teeth can also be present on the lateral submarginal papillae, infraangular lateral flap, or on either side of the anterior labium. There may be constriction on the body at the supraangular regions of the oral disc (Kolenc et al. 2008).

The larval stage is long and can last eight months, as some tadpoles may postpone metamorphosis throughout the winter (Langone 1994).

Trends and Threats
The species is listed as “Least Concern” on the IUCN Red List (Baraquet et al. 2021).

Comments
The hylid genus Boana includes over 90 species found throughout Latin America, ranging from Nicaragua to central Argentina. These species used to be grouped into the Hyla genus, but in 2005, they were reorganized by Faivovich et al. (2021) into species groups within Boana. As of 2025, there are eight species groups within Boana, one of which is the B. pulchella group, the most species-rich. Though the groups were initially made based on phenotypic characters, recent molecular phylogenetic analyses (Faivovich et al. 2021) have affirmed the validity of the groups.

The sister group to the B. pulchella group is the B. claresignata group. The sister species to B. pulchella is B. cordobae; both are part of the B. prasina complex within the B. pulchella group. The next most closely related complex is the B. riojana complex (Faivovich et al. 2021).

References
Achaval, F., and Olmos, A. (2003). Hyla pulchella pulchella. In Anfibios y Reptiles del Uruguay (2da Edición corregida y aumentada, Ser. Fauna, pp. 41–41). Facultad de Ciencias.

Baraquet, M., Otero, M. A., Grenat, P. R., Babini, M. S., and Martino, A. L. (2018). Morphometric differentiation and geographic variation among populations of Boana cordobae (Anura: Hylidae): Effect to age. Revista de Biología Tropical, 66(4), 1401. [link]

Baraquet, M., Pollo, F. E., Otero, M. A., Grenat, P. R., Salas, N. E., and Martino, A. L. (2021). Body size, age and growth in males populations of Boana pulchella (Anura, Hylidae). Anais Da Academia Brasileira de Ciências, 93(suppl 4), 1-12. [link]

de Amaral, M., Von Dentz, M. C., Ohlweiler, R., Hoff, M. L., Heiermann, D., Colombo, P., and Kucharski, L. C. (2021). Seasonal variations in the intermediate metabolism in South American tree-frog Boana pulchella. Journal of Comparative Physiology B, 192(2), 297–311. [link]

Duellman, W. E., De La Riva, I., and Wild, E. R. (1997). Frogs of the Hyla armata and the Hyla pulchella groups in the Andes of South America, with definitions and analyses of phylogenetic relationships of Andean groups of Hyla. Scientific Papers, Natural History Museum, the University of Kansas, 3, 1-41. [link]

Faivovich, J., D.P. Pinheiro, P., Lyra, M. L., Pereyra, M. O., Baldo, D., Muñoz, A., Reichle, S., Brandão, R. A., Giaretta, A. A., C. Thomé, M. T., Chaparro, J. C., Baêta, D., Libardi Widholzer, R., Baldo, J., Lehr, E., Wheeler, W. C., C. A. Garcia, P., and Haddad, C. F. B. (2021). Phylogenetic relationships of the Boana pulchella group (Anura: Hylidae). Molecular Phylogenetics and Evolution, 155, 106981. [link]

Grenat, P., Ferrero, M., Baraquet, M., Pollo, F., Otero, M., Salinas, Z., Salas, N., and Martino, A. (2023). Changes in call properties of Boana pulchella (Anura, Hylidae) in response to different noise conditions. Current Zoology, 70(4), 548–556. [link]

Kolenc, F., Borteiro, C., Alcalde, L., Baldo, D., Cardozo, D., and Faivovich, J. (2008). Comparative larval morphology of eight species of Hypsiboas Wagler (Amphibia, Anura, Hylidae) from Argentina and Uruguay, with a review of the larvae of this genus. Zootaxa, 1927(1). [link]

Langone, J. A. (1994). Hylidae. In Ranas y Sapos del Uruguay (Reconocimiento y aspectos biológicos) (pp. 46–48). Intendencia Municipal, Div. Cultura, Servicio de Divulgación Científica. [link]

Mahoney, K. D. (2025). Latin definition for: pulchellus, pulchella, pulchellum. Latin Dictionary at https://latin-dictionary.net/definition/32261/pulchellus-pulchella-pulchellum. Accessed on 18 March 2025.

Silveira, E. C., Mascarenhas, C. S., Huckembeck, S., Müller, G., and Loebmann, D. (2022). Parasitic helminths in Boana pulchella (Duméril & Bibron, 1841) (Anura: Hylidae) and their relation with host diet, body size, and habitat. Cuadernos de Herpetología, 36(2), 155–167. [link]

Species Account Citation: AmphibiaWeb 2025 Boana pulchella: Montevideo tree frog <https://amphibiaweb.org/species/705> University of California, Berkeley, CA, USA. Accessed May 29, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 29 May 2025.

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