Boreas Pigmy Salamander
© 2015 Sean Michael Rovito (1 of 9)
Thorius boreas can be distinguished from other species of Thorius by it having dark dorsal and ventral coloration, a larger size, relatively large nostrils, and lack of maxillary teeth. Two other species of Thorius have sympatric ranges with T. boreas. Thorius boreas can be distinguished from T. aureus by darker coloration, larger nostrils, and lack of maxillary teeth. From T. macdougalli it can be distinguished by T. boreas's larger size, robust body, and relatively smaller nostrils (Hanken and Wake 1994).
Thorius boreas can be further be distinguished from T. narisovalis by T. boreas being larger and having a more elongated nostril. Lastly, it can be distinguished from T. pulmonaris by elevation and by T. boreas being larger and having a smaller nostrils (Hanken and Wake 1994).
In life, T. boreas is very dark, especially dorsally and laterally. The ventrum is slightly lighter in color. There is an inconspicuous broad dorsal stripe with wavy boarders on the dorsum. The stripe may have lighter colored chevrons or partial chevrons corresponding to the costal grooves. The venter has fine white speckling along the ventrolateral margins of the body, but is uniform on the gular area, main trunk, and tail. The mental gland is light colored and the iris is charcoal (Hanken and Wake 1994).
In alcohol, the overall coloration of T. boreas is dark gray, particularly on the lateral sides, with a lighter, charcoal colored venter. An inconspicuous ebony dorsal stripe extends from eyes to base of tail and gradually disappears. The limbs are dark near the body but lighten in color toward the digits. Small gular guanophores are present. The mental gland appears white and the nasolabial protuberances are unpigmented (Hanken and Wake 1994).
There is very little variation in coloration (Hanken and Wake 1994).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
Thorius boreas belongs to the subfamily, Bolitoglossinae. Thorius species likely evolve via adaptive radiation. Based on analysis of mtDNA and RAG1 sequences data, T. boreas is sister to T. aureus (99% posterior probability) and together they are sister to the clade including T. narisovalis and T. minutissimus (Rovito et al. 2013).
The species epithet, boreas, is Greek for “the north wind” and refers to the fact that the species’ elevation range is cool montane peaks above 2850 m (Hanken and Wake 1994).
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.
Parra-Olea, G., Wake, D.B., Hanken, J., García-París, M. (2008). Thorius boreas. The IUCN Red List of Threatened Species. Version 2014.3. www.iucnredlist.org. Downloaded in May 2015
Rovito, S. M., Parra-Olea, G., Hanken, J., Bonett, R. M., Wake, D. B. (2013). ''Adaptive radiation in miniature: the minute salamanders of the Mexican highlands (Amphibia: Plethodontidae: Thorius).'' Biological Journal of the Linnean Society, 109, 622-643.
Written by Erica J. Ely (eely AT nevada.unr.edu), University of Nevada, Reno
First submitted 2015-12-22
Edited by Ann T. Chang (2015-12-22)
Species Account Citation: AmphibiaWeb 2015 Thorius boreas: Boreas Pigmy Salamander <http://amphibiaweb.org/species/4204> University of California, Berkeley, CA, USA. Accessed Feb 16, 2019.
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