Description
Bolitoglossa tapajonica is a relatively small salamander. In males, the standard length varies from 38.8 - 42.8 mm and 35.5 - 49.3 mm in females. The head is somewhat flattened in appearance, with a width of 5.3 - 6.1 mm in males and 4.7 - 6.8 mm in females. The head is approximately as wide as the neck. The snout is short, and measures 1.8 - 2.4 mm in males and 1.8 - 2.8 mm in females. The snout protrudes by 0.8 - 1.1 mm in males and 0.6 - 1.0 mm in females. Some specimens display a slight concave area near the end of the snout. Mental glands are present in males, and measure 2.7 - 3.1 mm wide. Nasal protuberances were present in both males and females. The eyes are prominent and protrude from the head. The orbital diameter measures 2.1 - 2.4 mm in males, and 1.6 - 2.2 mm in females. The limbs are slim and short. From largest to smallest, fingers are ordered 3 - 2 - 4 - 1. The length of the third finger measures 2.3 - 2.8 mm in males and 1.9 - 2.8 in females. Toes from largest to smallest follow the order 3 - 2 - 4 - 5 - 1, and the third toe measures 2.9 - 3.4 mm in males and 2.1 - 3.4 mm in females. The tail is also relatively short, measuring 28.4 - 35.4 mm long in males and 25.9 - 37.4 mm in females (Brcko et al. 2013).

DIAGNOSIS:

COLORATION:

In preservative, the dorsal color can range from gray to dark brown with varied patches of lighter shades of brown. Some specimens are spotted while others have light gray stripes. Spots are mainly present on the top of the head, and mid-dorsal region. A dark gray stripe is present on the dorsolateral side. The snout remains lighter than the body and is cream with specks above nasolabial protuberances. The limbs now appear a pale gray. Mental glands are present and appear light gray. The ventral surface can be light to dark brown, or lacking color entirely near the anterior of the ventral surface (Brcko et al. 2013).

VARIATION:

Coloration can vary in preservative (See above, Brcko et al. 2013).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil

View distribution map in BerkeleyMapper.

As of 2024, B. tapajonica has only been found in the western part of Pará, Brazil. The species occupies a small area south of the Amazon River and on both sides of the Tapajós River for which it is named. Specimens were collected between 78 and 155 m above sea level. A single specimen was collected on the West Bank of the Xingú River, an area well east of the Tapajos River, raising questions about the true range of this species (Brcko et al. 2013).

Life History, Abundance, Activity, and Special Behaviors
Specimens were usually found on the leaves of small vegetation but were also collected from the ground. Specimens were collected at night when B. tapajonica is most active (Brcko et al. 2013).

Larva
As a Plethodon, this species is expected to reproduce via direct development.

Trends and Threats
As of 2024, IUCN lists the B. tapajonica as a species of “Least Concern”. However, there are six hydroelectric projects currently proposed for the Tapajós River. If constructed, these dams would flood much of the surrounding land and cause it to be uninhabitable (IUCN 2021).

Possible reasons for amphibian decline

Dams changing river flow and/or covering habitat

Comments
Researchers conducted a stepwise discriminant function analysis on the morphology of Brazilian specimens of Bolitoglossa that resulted in the description of three new species: B. caldwellae, B. madeira, and B. tapajonica. In this analysis, they used 13 characteristics: standard length, head length, snout to gular fold, head width, snout length, orbital diameter, interorbital distance, axilla to snout, snout width at the narrowest point, snout projection beyond mandible, axilla to groin, length of third toe, and eyelid width. The first discriminant factor accounted for 81% of the variation, and the first and second discrimination factors together accounted for 100% of species variation. The length of the third toe was the first characteristic selected, and correctly identified 64% of specimens. After adding the rest of the characteristics, species were confidently identified 90% of the time, with an 88% jackknife (Brcko et al. 2013).

References
Brcko, I. C., Hoogmoed, M. S., and Neckel-Oliveira, S. (2013). Taxonomy and distribution of the salamander genus Bolitoglossa Duméril, Bibron & Duméril, 1854 (Amphibia, Caudata, Plethodontidae) in Brazilian Amazonia. Zootaxa, 3686(4), 401-431. [link]

IUCN SSC Amphibian Specialist Group & Instituto Boitatá de Etnobiologia e Conservação da Fauna. (2023). Bolitoglossa tapajonica. The IUCN Red List of Threatened Species 2023: e.T81659800A86254599. https://dx.doi.org/10.2305/IUCN.UK.2023-1.RLTS.T81659800A86254599.en. Accessed on 4 December 2024.

Species Account Citation: AmphibiaWeb 2024 Bolitoglossa tapajonica: Tapajos Mushroomtongue Salamander (English) <https://amphibiaweb.org/species/8029> University of California, Berkeley, CA, USA. Accessed May 5, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 5 May 2025.

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