Description
Bolitoglossa riletti has a snout-to-vent length of 60.9 millimeters. This length was only obtained from the juvenile female holotype, and insufficient information has been found about the range in snout-to-vent length within the species. Males have a total length of 36.9 – 52.1 millimeters, and females have a total length of 31.4 mm – 54.4 mm. It has a shortened snout, and the region between the nostril and the edge of its eye is rounded. Males lack a mental gland underneath the chin. There is a noticeable fold on its throat. There are 13 costal grooves present. The tail only shows a slight basal constriction, and is almost as long as the body. Hands and feet are moderately webbed, with the webbing reaching the most distal phalanx only at digit I. The tips of its digits are shortened. No information is available on the relative lengths of its fingers and toes (Holman 1964, Papenfuss et al. 1983).

Bolitoglossa riletti has intermediately webbed hands and feet, whereas B. hermosa is fully webbed and B. macrinii has no webbing at all. Compared to B. macrinii in particular, B. riletti lacks maxillary teeth, but has undifferentiated vomerine and paravomerine teeth. It is only half as large as B. macrinii, with only a slight basal constriction on the tail, and has different coloration. Bolitoglossa riletti closely resembles B. rufescens with the only difference being in their foot structure. Compared to B. nigroflavescens, B. riletti has shorter legs that do not touch when adpressed, and has two costal folds between adpressed limbs. Bolitoglossa riletti has longer legs than B. brevipes, and B. brevipes shows five and a half costal folds between adpressed limbs (Papenfuss et al. 1983, Holman 1964).

In life, its underside is bright yellow, and extends transversely across the pectoral region and down both sides of the specimens so the color is transverse to the body, anterior to the thighs, along with on the ventral area of the thighs. Adult coloration shows small cream-colored spots on dark skin, although the spots are scattered flecks in some individuals. In alcohol, the body and head are light brownish above, and show faint dorsolateral stripes. In the holotype, a middorsal stripe originates at the level of the hind legs, and continues to the back of the head where it bifurcates, and the bifurcation ends on the posteromedial borders of the eyelids. However, the middorsal stripe is only present in juveniles. The sides of both the head and body are dark brown, along with the legs. The chin has light yellow flecks, and the venter light gray (Holman 1964, Papenfuss et al. 1983).

Some specimens show a dorsum mottled with yellow, and chin flecks in some individuals are reduced or lacking. The bifurcated mid-dorsal stripe ends right at the eyelids in juveniles, and ends behind the eyes in other individuals. Only sexually mature individuals show maxillary teeth (Holman 1964, Papenfuss et al. 1983).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico

View distribution map in BerkeleyMapper.

Bolitoglossa riletti has been noted along the Pacific slopes of the Sierra Madre del Sur, approximately 5.6 km south of Putla de Guerrero in the westernmost part of Oaxaca, Mexico, and has been found in Corral de Piedra, Santa Ana del Progresso (Parra-Olea et al. 2002; Canseco-Marquez and Gutierrez-Mayin 2005). The species has been found between 700 - 1030 meters in elevation (Papenfuss et al. 1983). The habitat for this region is classified as secondary tropical semi-deciduous forest (Canseco-Marquez and Gutierrez-Mayin 2005). Additionally, the habitat crosses over human-inhabited spaces, which are being used for the growth of banana trees and coffee plants (Parra-Olea et al. 2008). All specimens have been found on banana leaf axils or other broad-leafed plants (Papenfuss et al. 1983).

Life History, Abundance, Activity, and Special Behaviors
Few extensive studies have been conducted on this species, but their foot morphology indicates an arboreal lifestyle, and collected specimens were largely found on broad-leafed plants, such as the banana plant (Papenfuss et al. 1983). Bolitoglossa riletti is considered uncommon due to its limited range (Parra-Olea et al. 2008).

There is little study that has been done regarding the reproductive behavior of B. riletti. However, direct development is common in Bolitoglossinae (Vitt and Caldwell 2009). Individuals collected during the dry season showed reduced reproductive organs, suggesting that breeding occurs during the rainy season (Holman 1964).

Trends and Threats
More information is needed to draw definitive conclusions about the population numbers; however, it is believed that the population is currently decreasing due to (prior and current) habitat modification by logging, as well as changes in agricultural practices (Parra-Olea et al. 2008).

Relation to Humans
Little is known about the relationship between humans and Bolitoglossa riletti, however its habitat has been replaced with red-banana plantations by humans, which are now being replaced and fragmented by yellow-banana plantations (also by humans) (Parra-Olea et al. 2008).

Possible reasons for amphibian decline

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

Comments
The species authority is:
Holman, J. A. (1964). "New and Interesting Amphibians and Reptiles from Guerrero and Oaxaca, Mexico." Herpetologica 20.1: 48-64.

Based on molecular evidence, Bolitoglossa riletti is part of the Oaxakia clade within Bolitoglossa. It is a sister species to B. hermosa, and both are sister species to B. zapoteca. Bolitoglossa macrinii and B. oaxacensis are outgroups within the same Oaxakia clade. (Parra-Olea et al. 2003)

The species epithet “riletti” is named for Dr. R. Omar Riletti, an influential person behind the trip made by Ronald Altig, William Holmes Hill, and J. Alan Holman, who first described the species (Holman 1964).

Bolitoglossa in general are unique in their defense mechanisms, utilizing a tail-lashing movement that exposes predators to poison gland secretions along the tail (Vitt and Caldwell 2009).

Bolitoglossa are also physiologically unique in terms of their feeding technique. The tongue of Bolitoglossa is designed so that once the brain sends a signal to deploy it, the brain doesn’t have to send another to retract the tongue. The retractor muscles of the tongue are loose enough that they can contract at the same time as the extensor muscles and they won’t interfere with the trajectory of the tongue until it has reached its maximum length (Vitt and Caldwell 2009).

References

Canseco-Marquez, L., Gutierrez-Mayen, G. (2005). ''New Species of Pseudoeurycea (Caudata: Plethodontidae) from the Mountains of the Mixteca Region of Oaxaca, Mexico.'' Journal of Herpetology. 35, 2: 181-185.

Holman, J. A. (1964). ''New and Interesting Amphibians and Reptiles from Guerrero and Oaxaca, Mexico.'' Herpetologica 20.1: 48-54.

Ochoa-Ochoa, L., Urbina-Cardona, J. N., Vázquez, L.-B., Flores-Villela, O., and Bezaury-Creel, J. (2009). ''The effects of governmental protected areas and social initiatives for land protection on the conservation of Mexican amphibians.'' PLoS One, 4(9), e6878.

Papenfuss, T. J., Wake, D. B., Adler, K. 1983. Salamanders of the Genus Bolitoglossa from the Sierra Madre Del Sur of Southern Mexico. Journal of Herpetology 17.4: 295-307.

Parra-Olea, G., García-París, M., Wake, D. B. (2004). ''Molecular diversification of salamanders of the tropical American genus Bolitoglossa (Caudata: Plethodontidae) and its evolutionary and biogeographical implications.'' Biological Journal of the Linnean Society, 81, 325-346.

Parra-Olea, G., Papenfuss, T. J., Wake, D. B. 2008. Bolitoglossa riletti. The IUCN Red List of Threatened Species. Version 2014.3. www.iucnredlist.org.

Vitt, L. J., Caldwell, J. P. 2009. Herpetology 3rd ed. Elsevier Inc.

Species Account Citation: AmphibiaWeb 2015 Bolitoglossa riletti: Rilett's climbing salamander <https://amphibiaweb.org/species/4006> University of California, Berkeley, CA, USA. Accessed Nov 22, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Nov 2024.

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