Description
Bolitoglossa tenebrosa has a snout-to-vent length of 51.12 – 58.88 mm in males and 56.83 – 81.37 mm in females. The head is longer than wide. The eyes are large, approximately 1/4 to 1/3 the width of the head and separated by slightly more than an eye distant. The distance between the nares is slightly less than one eye distance and the snout projects beyond the mandible. Lip projections are not very prominent or developed. It has fairly short limbs; adpressed limbs are separated by two costal folds. Its tail is around the same length as its body. It has reduced webbing, and two phalanges on digit III lack webbing on both its hands and feet. The relative finger lengths are as follows: I < II ≈ IV < III. The relative toe lengths are as follows: I < II < V < IV < III (Vásquez-Almazán and Rovito 2014).

In life, this species is solid black on its head, tail, and dorsal surface of its body. From a ventral view, it is light grey. In a preservative, the dorsal view of the body, head, tail, and limbs are dark grey. However, the upper surface of the feet is light grey-brown. From a ventral view, the body appears light grey with the intersection of the forelimbs looking light brown. There is a light brown color at the throat with a light streak of light grey going across behind the gular fold. The bottom of the tail is also light grey while the bottom of the limbs and phalanges are light grey-brown (Vásquez-Almazán and Rovito 2014).

The external features, specifically dark coloration, of species within Bolitoglossa (subgenus Magnadigita) have made individual identification and separation difficult. Like other species of Bolitoglossa, B. tenebrosa does not have a sublingual fold. The reduced toe and finger webbing as well as genetic information assigned it to the subgenus, Magnadigita. Moreover, its lack of fully webbed feet differentiates it from members of the subgenera Bolitoglossa, Nanotriton, Pachymandra, and Mayamandra. This species differs from Eladinea and Oaxakia due to genetic differences as well as the presence of a first caudal vertebra with branched transverse processes. Unlike all species within its subgenus except for B. meliana, this species has no spots or color. Its larger size also distinguishes it from B. omniumsanctorum, B. lincolni,and B. franklini. While both B. tenebrosa and B. meliana are the same uniform black color, B. tenebrosa males and females both have longer tails and broader heads, and also have more maxillary and vomerine teeth. Its longer tail length also differentiates it from B. tzultacaj (Vásquez-Almazán and Rovito 2014). In life, this species is solid black on its head, tail, and dorsal surface of its body. From a ventral view, it is light grey. In a preservative, the dorsal view of the body, head, tail, and limbs are dark grey. However, the upper surface of the feet is light grey-brown. From a ventral view, the body appears light grey with the intersection of the forelimbs looking light brown. There is a light brown color at the throat with a light streak of light grey going across behind the gular fold. The bottom of the tail is also light grey while the bottom of the limbs and phalanges are light grey-brown (Vásquez-Almazán and Rovito 2014).

Other than measurements, there is no information available on variation within the species (Vásquez-Almazán and Rovito 2014).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Guatemala

View distribution map in BerkeleyMapper.

This species has only been found in Guatemala. All observed specimens of B. tenebrosa have been found in elevations ranging from 1,585 – 2,727 m. They occupy broadleaf cloud forest habitat from the highlands of the eastern side of Depto. Baja Verapaz to the southern portion and top of the Sierra de las Minas in the Depto. El Progreso and Zacapa (Vásquez-Almazán and Rovito 2014).

Life History, Abundance, Activity, and Special Behaviors
Most individuals have been observed near rotten logs and under bark. However, despite only finding one specimen in vegetation approximately 2 m off the ground, this species has the potential to be arboreal due to its prehensile tail (Vásquez-Almazán and Rovito 2014).

Trends and Threats
Fires and illegal activities threaten B. tenebrosa habitat despite the Sierra de las Minas being a protected reserve. Human activity and felling of nearby forests has also caused disturbances within habitat at the Biotopo del Quetzal (Vásquez-Almazán and Rovito 2014).

Possible reasons for amphibian decline

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

Comments
The species authority is:
Vásquez-Almazán, C. R., S. M., Rovito. 2014. A New Species of Black Bolitoglossa (Caudata: Plethodontidae) from Guatemala. Journal of Herpetology 48:518–524.

Despite its similar morphology, molecular data do not support that B. tenebrosa is a sister taxon to B. meliana. Instead, molecular data suggest that this species is a distinct species in subgenus Magnadigita (Vásquez-Almazán and Rovito 2014).

The epithet tenebrosa comes from a Latin root meaning “dark” which refers to both the black coloration as well as the problem of this species being misidentified for many years as B. meliana (Vásquez-Almazán and Rovito 2014).

References

Vasquez-Almazan, C. R., Rovito, S. M. (2014). ''A New Species of Black Bolitoglossa (Caudata: Plethodontidae) from Guatemala.'' Journal of Herpetology, 48, 518-524. [link]

Species Account Citation: AmphibiaWeb 2015 Bolitoglossa tenebrosa: Guatemalan Black Salamander; Salamandra Negra Guatemalteca <https://amphibiaweb.org/species/8295> 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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