Description

Diagnosis: Bolitoglossa robusta is a large, robust salamander species, one of the 2-3 largest neotropical salamanders, with adult standard length frequently exceeding 100 mm and maximum total length of 260 mm (Hanken et al. 2005; Savage 2002). It is distinct from other species of Bolitoglossa in having a light-colored ring around the base of the tail (Hanken et al. 2005).

Description: The mean SL of adult males is 83.4 mm (range 44.6-113.9 mm); adult females 105.1 mm (range 64.9-133.5 mm). Mean SL/TL is 1.09 (range 0.9-1.5). The snout is rounded to subtruncate. Nostrils are small. asolabial protuberances are poorly developed or absent in females, and moderately developed in males. The mental gland of adult males is conspicuous, gray in color and wider than long. Eyes are fairly large, and protrude slightly beyond the jaw margins in dorsal view. Premaxillary teeth average 6.1 in number (range 4-8) in males and 8.5(5-12) in females; maxillary teeth 65.5(31-100) in males and 84.6(60-102) in females; vomerine teeth 28.9(18-40) in males and 33.9(25-41) in females. Males have slightly enlarged premaxillary teeth that protrude anteriorly through the upper lip. Some specimens have vomerine teeth in patches formed by extra tooth rows in the distal part of the preorbital process. The limb interval is 3.0 in males and 3.3 in females. Limbs are short. Hands and feet are webbed except for 1 to 1.5 distal-most phalanges of longest digits, and are moderately sized with broad, truncated digit tips. Subterminal pads are present on all digits. Fingers in decreasing order of length are 3>(2>4)>1, while toes are 3>4>2>5>1 (Hanken et al. 2005).

In life, the salamander is black overall with a pale pigmented ring around the base of the tail. The tail ring is cream-colored, golden, rose, or red-orange and may be faint or more prominent. Elbows, knees and tail tip are brown. The venter is mottled with gray. The throat is black but may have white speckling. The mental gland is slightly pigmented. Postiliac gland is visible but pale. Dorsal surfaces of the femur and forelimb may have coppery pigment. Some individuals have white dorsal spotting, particularly individuals from Panamá; some individuals from Costa Rica may have a suffusion of white speckles on the lateral and dorsal sides Tail may have irregular bold whitish spots, particularly laterally and ventrally. Iris is dark gray to black. Juveniles have bright yellow to orange feet (Hanken et al. 2005; Savage 2002).

In preservative, it is dark gray-black with a cream-yellow or gray-white ring around the base of the tail. Tiny white flecks near eyelids and jaws, and on gular region, and ventral surfaces of limbs and tail, and some indistinct flecks on the dorsolateral surfaces. Pair of inguinal spots may be present. Tail may have lighter patches on the sides (Hanken et al. 2005).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Costa Rica, Panama

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

This species is is the most widely distributed species of large black Bolitoglossa, and occurs from northern Costa Rica (Volcán Cacao, Guanacaste Province) to western Panamá (near Fortuna Dam, Chiriquí Province). It inhabits tropical premontane and lower montane rainforest. It occurs from 650 to 2100 m asl, but most individuals are found between 1000 and 1600 m asl. B. robusta is commonly found under fallen logs, in leaf litter, or under moss. (Hanken et al. 2005).

Life History, Abundance, Activity, and Special Behaviors
It has been seen walking on the ground at night and on bamboo 40 cm above ground. Bolitoglossa robusta may occur in sympatry with B. obscura in the northern parts of the Cordillera de Talamanca-Barú and B. anthracina in the southern parts of the Cordillera de Talamanca-Barú (Hanken et al. 2005). It breeds by direct development (Solís et al. 2008).

Trends and Threats
Habitat loss is a threat, due to increased agriculture and wood extraction, but this species also occurs in a number of protected areas. In Costa Rica, it is found in the Montverde Biological Reserve, Volcán Irazu National Park, Volcán Poas National Park, Braulio Caurillo National Park, and Guanacaste National Park, as well as in La Amistad National Park. In Panama it occurs in Fortuna National Park and La Amistad National Park (Solís et al. 2008).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing

Comments

First described by Cope (1894), and redescribed by Hanken et al. (2005). The specific name derives from the Latin word robustus, meaning strong and hard like an oak and referring to the large and stout body (Hanken et al. 2005).

A Spanish-language species account can be found at the website of Instituto Nacional de Biodiversidad (INBio).

References

Cope, E. D. (1894). ''Third addition to a knowledge of the batrachia and reptilia of Costa Rica.'' Proceedings of the Academy of Natural Sciences of Philadelphia, 46, 194-206.

Hanken, J. Wake, D. B., and Savage, J. M. (2005). ''A solution to the large black salamander problem (genus Bolitoglossa) in Costa Rica and Panamá.'' Copeia, 2005(2), 227-245.

Savage, J. M. (2002). The Amphibians and Reptiles of Costa Rica:a herpetofauna between two continents, between two seas. University of Chicago Press, Chicago, Illinois, USA and London.

Solís, F., Ibáñez, R., Savage, J., Wake, D., Chaves, G., and Bolaños, F. 2008. Bolitoglossa robusta. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. www.iucnredlist.org. Downloaded on 11 March 2011.

Stuart, S., Hoffmann, M., Chanson, J., Cox, N., Berridge, R., Ramani, P., Young, B. (eds) (2008). Threatened Amphibians of the World. Lynx Edicions, IUCN, and Conservation International, Barcelona, Spain; Gland, Switzerland; and Arlington, Virginia, USA.

Species Account Citation: AmphibiaWeb 2011 Bolitoglossa robusta: Ringtail Salamander <https://amphibiaweb.org/species/4007> University of California, Berkeley, CA, USA. Accessed Jan 14, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 14 Jan 2025.

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