Description
Bolitoglossa pacaya is a small to mid-sized salamander with the adult form ranging from 36 – 49 mm in standard length. Males reach a maximum standard length of 45.8 mm and females reach a maximum standard length of 48.6 mm. Generally, the tail length is 0.66 - 0.83 percent of the standard length. Individuals are smaller in size than other members of the genus. The head is longer than wide. The internarial distance is slightly shorter than the distance between eye and nostril. The length of the eye is slightly smaller than both the internarial distance and the distance between the eye and the nostril. The interocular distance is more than twice the eye length and slightly less than twice the internarial distance. The species has costal grooves. When the limbs are adpressed along the body, the number of costal grooves between them is 0.5 - 2.5. This species has webbed feet, but only the first toe has full webbing. The digits of the species are wide and dull-edged. The hands are narrower than the feet. This species displays a folded vent with papillae on the anterior side (Campbell et al. 2010).

DIAGNOSIS:

Bolitoglossa pacaya differs from most other members of the genus by its small size. Specifically, the species differs from B. mexicana and B. dolfeini in the former having a smaller overall size and the absence of fully webbed feet. Its partially webbed feet can also distinguish it from B. cuchumatana, B. flavimembris, B. hartwegi, B. helrichi, and B. stuarti. Longer limbs and larger extremities in B. pacaya also help distinguish it from B. cuchumatana. Bolitoglossa pacaya have a shorter tail length and more costal grooves in females than B. morio. In addition, B. morio is larger in size, has longer extremities, and has fewer premaxillary and maxillary teeth. A smaller number of premaxillary, maxillary, and vomerine teeth is also seen in B. kaqchikelorum than in B. pacaya. Bolitoglossa huehuetenanguensis is bigger in size, has a longer tail, a greater number of vomerine teeth, and larger hands and feet than B. pacaya. Larger body sizes and the pattern seen on the underbelly of B. pacaya differentiate it from B. engelhardti . Unlike B. pacaya, B. lincolni individuals are found in the Sierra de los Cuchumatanes, and they feature a thick reddish band on their dorsal side. Bolitoglossa pacaya individuals also have more webbing than B. lincolni. Bolitoglossa meliana are more solid black in color and have more webbing on hands and the feet than B. pacaya (Campbell et al. 2010).

COLORATION:

In life, color patterns on the dorsal side greatly varies between three color variations, usually displayed as a band of black, dark brown, or orange-brown. The dorsolateral parts are usually yellowish-tan. The coloration on the sides of the body is usually dark gray or black with an abundant amount of light blue or light gray marks. The underbelly is dark gray or black with more pale gray or blue marks, that sometimes appear to be lumped. The dorsal side of the head is usually black or dark gray stretching from the muzzle to the parietal region. The extremities are lighter than what is observed on the dorsal side and usually feature blotched markings. The vent that is lightly colored on the posterior side but unpigmented on the anterior side. The tip of the tail is usually yellow or black. In preservative, the dorsum of the holotype is medium brown with a blackish brown lateral stripe. The ventrum is pale with a dark midline and gradually shifts to the coloration on the flanks. The ventrum also has many pale brown flecks (Campbell et al. 2010).

VARIATION:

Besides variation in coloration (see above), females are typically larger than males. The number of vomerine teeth range between 14 - 28 (Campbell et al. 2010).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Guatemala

View distribution map in BerkeleyMapper.

Bolitoglossa pacaya can be found in the western part of the Jalapan area in Guatemala. They occur on the Volcán de Pacaya, inhabiting the highlands that extend below the 1,500 m contour from the northeast side of the volcano to the western edge of Lago Amatitlán. The highlands consist of humid hardwood or pine-oak forests at an elevational range of 1,700 to 2,300m. They have often been found living in bromeliads growing on hardwood trees, however, individuals have also been found under rotting logs and in deep crevices along dirt banks (Campbell et al. 2010).

Life History, Abundance, Activity, and Special Behaviors
Bolitoglossa pacaya have often been found living in bromeliads growing on hardwood trees, however, individuals have also been found under rotting logs and in deep crevices along dirt banks (Campbell et al. 2010).

Although specific information on B. pacaya is limited, species in the genus Bolitglossa are direct developers with development occurs within the eggs, commonly found on the ground, under rocks, or in decaying logs (Wake and Hanken 1996, Vial 1968). There is no metamorphosis (Wake and Hanken 1996). Bolitoglossa males are sexually mature between 4 - 9 years of age while sexually mature females range between 9 - 14 years of age (Vial 1968).

Bolitoglossa pacaya and B morio, closely related species, can be found in micro-sympatry, using the same bromeliads with similar characteristics in Volcan Pacaya. It is an unusual finding because two closely related species occupying the same habitat should, in theory, result in one excluding the other. This leaves the question of what aspect of their natural history differs to allow them to coexist (Ruano-Fajardo et al. 2014).

Trends and Threats
Bolitoglossa pacaya is currently facing a decrease in population. Although abundant in its known range, the population of B. pacaya is highly fragmented due to patchy environments. This species faces many different threats including residential and commercial development, agriculture and aquaculture, transportation and service corridors, biological resource use, geological events, invasive/problematic species, and disease. Volcán de Pacaya contains many protected areas, however, they are loosely regulated as the species population continues to decline (IUCN 2020)

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Predators (natural or introduced)
Introduced competitors
Disease

Comments

PHYLOGENETIC RELATIONSHIPS:

ETYMOLOGY:

The species epithet comes from where they are found, Volcan de Pacaya. In turn, “pacaya” is a term used to describe different species of palms. These palms are very common in subtropical and humid tropical forests (Campbell et al. 2010).

References

Campbell, J. A., Smith, E. N., Streicher, J., Acevedo, M. E., Brodie, E. D. Jr. (2010). "New salamanders (Caudata: Plethodontidae) from Guatemala, with miscellaneous notes on known species." Miscellaneous Publications Museum of Zoology University of Michigan, 200, 1-66. [link]

IUCN SSC Amphibian Specialist Group. 2020. "Bolitoglossa pacaya". The IUCN Red List of Threatened Species 2020: e.T194321A2312288. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T194321A2312288.en. Downloaded on 18 February 2021.

Jaramillo, A. F., De La Riva, I., Guayasamin, J. M., Chaparro, J. C., Gagliardi-Urrutia, G., Gutiérrez, R. C., Brcko, I., Vilà, C., Castroviejo-Fisher, S. (2020). "Vastly underestimated species richness of Amazonian salamanders (Plethodontidae: Bolitoglossa) and implications about plethodontid diversification." Molecular phylogenetics and evolution, 149, 106841. [link]

Ruano-Fajardo, G., Rovito, S. M., Ladle, R. J. (2014). ''Bromeliad selection by two salamander species in a harsh environment.'' PLos ONE

Vial, J. L. (1968). ''The ecology of the tropical salamander, Bolitoglossa subpalmata, in Costa Rica.'' Revista de Biologia Tropical, 15, 13-115.

Wake, D. B., Hanken, J. (1996). "Direct development in the lungless salamanders: what are the consequences for developmental biology, evolution, and phylogenesis?" International Journal of Developmental Biology, 40, 859-869. [link]

Species Account Citation: AmphibiaWeb 2021 Bolitoglossa pacaya <https://amphibiaweb.org/species/7560> University of California, Berkeley, CA, USA. Accessed Nov 26, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 26 Nov 2024.

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