Thorius arboreus
Arboreal Thorius
family: Plethodontidae
subfamily: Hemidactyliinae

© 2010 Sean Michael Rovito (1 of 4)
Conservation Status (definitions)
IUCN (Red List) Status Endangered (EN)
Other International Status None
National Status None
Regional Status None


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This is a very small species of Thorius. Average length in four adult males was 17.0 mm (range 16.1-18.4mm). In seven females the mean length was 17.2 mm (range 15.2-20.0). The salamander have a very slender body and a relatively wide head with a bluntly pointed snout. The mean ratio of SL to head width is 6.7 in both males and females (range 6.1-7.3). The nostril is round or slightly oval; the mean ratio of major to minor axis is 1.3 (range 1.0-1.7). The eyes are moderately large and protrudant. There is a suborbital groove intersecting the lip on both sides. Individuals of the species have very few teeth. Some have one premaxilliary tooth. Mean number of vomerine teeth is 6 (range 5-7) in males and 4.5 (range 4-5) in females. Limbs are long; limb intervals were 4 in one male and average of 3.4 in females (range 2-4.5). Hands and feet are narrow. The tail is relatively long and tapers from midpoint to tip.

The species has a reddish dorsal stripe. Some individuals may have an ornate pattern, others a normal stripe. Legs and venter may be lighter in color. Also, there may be whitish spots on the tip of the snout and below the eye (Hanken and Wake 1994).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico


View distribution map using BerkeleyMapper.
Country range is Mexico. The range is known from type locality and other nearby cloud forest localities along Hwy 175 on the Atlantic draingage of the Sierra de Juarez. The lowest recorded elevation is 2170 m.The species is sympatric with T. aureus at upper elevations (Hanken and Wake 1994).The species may be common in warm areas under the bark of rotting logs (Feder 1982).


Feder, M.E. (1982). ''Thermal ecology of the Neotropical lungless salamanders (Amphibia: Plethodontidae); Environmental temperatures and behavioral responses.'' Ecology, 63(6), 1665-1674.

Hanken, J., Wake, D. B. (1994). ''Five new species of minute salamanders, genus Thorius (Caudata: Plethodontidae), from Northern Oaxaca, Mexico.'' Copeia, 1994(3), 573-590.

Written by Cailin O'Connor (coconnor AT, bio 269 seminar at Harvard University taught by James Hanken and David Wake
First submitted 2002-11-25
Edited by Meredith Mahoney (2003-02-05)

Species Account Citation: AmphibiaWeb 2003 Thorius arboreus: Arboreal Thorius <> University of California, Berkeley, CA, USA. Accessed Mar 17, 2018.

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Citation: AmphibiaWeb. 2018. <> University of California, Berkeley, CA, USA. Accessed 17 Mar 2018.

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