Description
Chiropterotriton nubilus is a slender-bodied, moderate-sized plethodontid salamander described from two females and one male. The two female specimens have a longer snout-vent length than the male with snout-vent lengths of 27.7 and 33.2 mm in females and 29.4 mm for the male. The head is relatively narrow yet moderately long. The snout is narrow and truncated. The nostrils are moderately sized and oval in shape. The eyes are slightly protuberant and the jaw muscles appear as a bulging mass behind the eyes, and are visible beyond the jaw margin. Males have only a few maxillary teeth versus females that have many. Both male and female have few vomerine teeth that are arranged in a well-defined line on the outer margin of the choanae. The limbs are short and slender, and when adpressed towards each other are separated by 2.0 costal folds in both males and females. The digits are slender with distinct terminal pads and moderate webbing just above the penultimate phalanx with phalangeal formula of the hand being 1 - 2 - 3 - 2 and foot being 1 - 2 - 3 - 3 - 2. The relative digits lengths increase in the following order: hand I - IV - II - III, foot I - V - II - IV - III. The tail is relatively long and a sublingual fold is present (Garcia-Castillo et al. 2018).

DIAGNOSIS:

Other species in the genus Chiropterotriton that have similar characteristics include C. arboreus, C. aureus, C. chico, C. chiropterus, C. dimidiatus, C lavae, C. magnipes, C. masaueri, C. miquihuanus, C. multidentatus, C. orculus, and C. priscus. Chiropterotriton nubilus is shorter than C. arboreus, C. magnipes, C. mosaueri, C. multidentatus, and C. priscus. Meanwhile, C. nubilus has a longer body size than C. chondrostega, C. cracens, C. dimidiatus, and C. terrestris. Additionally, C. nubilus has smaller feet than C. arboreus, C. cieloensis, C. chico, C. infernalis, and C. priscus. However, C. nubilus has relatively shorter limbs than C. arboreus, C. cieloensis, C. infernalis, and C. multidentatus, but relatively longer limbs than C. dimidiatus, C. miquihuanus, and C. priscus. In comparison to C. aureus, female C. nubilus are longer and have longer limbs and feet than female C. aureus. Female C. nubilus also have longer and broader heads than female C. aureus. Female C. nubilus have more rounded digits and slightly more webbing than female C. aureus. Meanwhile, male C. nubilus have longer tails than male C. aureus. In comparison to C. chiropterus, C. nubilus has smaller feet with rounded digits, and the fourth finger of hand and fifth toe of foot are longer than C. chiropterus. Additionally, C. nubilus has more webbing that extends to just above the penultimate phalanx while C. chiropterus has webbing under the penultimate phalanx. Chiropterotriton nubilus are shorter and males have shorter limbs and heads than C. chiropterus. Chiropterotriton nubilus also have narrower heads with less pronounced jaw muscles, and less protuberant eyes than C. chiropterus. In general, C. nubilus is morphologically similar to C. lavae in body size and proportions. However, C. nubilus males are shorter than C. lavae males, and both sexes have a longer tail than C. lavae. Additionally, C. nubilus has a narrower head, shorter limbs, smaller feet, less webbing between their toes, and more maxillary teeth than C. lavae. In comparison to C. orculus, C. nubilus are shorter, have a longer tail, have relatively longer limbs in females, have a shorter/narrower head, have more maxillary teeth, and have smaller feet. In comparison to C. dimidiatus, C. nubilus are shorter, have a longer tail, have a longer/broader head, have relatively longer limbs, have more maxillary teeth, have more vomerine teeth, and have longer feet (Garcia-Castillo et al. 2018).

COLORATION:

In life, the dorsal colors are salmon on a sepia-colored background. The ventral color, including the underside of the head as well as the lateral side of the head are cream white. The dorsal flanks are also cream white but with smoky white stipples. The upper side of the limbs are maroon, while the toe tips are magenta. The underside of the limbs are cream white with bluish-grey marks (Garcia-Castillo et al. 2018).

In alcohol, the overall dorsal color is dark yellow buff on a dusky brown surface. The ventral color is smoke gray, while the dorsal flanks are olive gray. The upper side of the head is drab with a dusky brown lateral line. The predominant color of the underside of the head is smoke gray with smoky white marks. The color of the underside of the tail is grayish horn. The dorsal side of the limbs are olive brown, while the ventral side of the limbs are smoke gray (Garcia-Castillo et al., 2018).

VARIATION:

Only one male and two females were used for the species description, so sexual dimorphism is difficult to assess. The mean snout-vent length is slightly longer in the females than the male (30.5 in females and 29.4 for the male), males have a longer relative tail, females have relatively longer limbs and a longer, broader head. Females also has longer feet. Outside of sex, there are also some color variation within C. nubilus. The upper side of the head may be a pale horn color with dark brownish olive coloring on the surface with the later part of the head being ream white and pale buff on the underside. The dorsum may have two stripes that are pale horn colored on a sepia surface, the lateral dorsum being a light lavender and underside a pinkish white with small purple dots. The upper side of the tail may also be a pinkish white with medium purple dots and pale horn colored speckles. Forelimbs can be cream colored while the hind limbs are more fawn colored with toe tips having a magenta tint (Garcia-Castillo et al. 2018).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico

View distribution map in BerkeleyMapper.

The distribution of C. nubilus is located along the eastern slopes of Cofre de Perote in central Veracruz, Mexico. Their elevation is between 1,520 and 2,023 meters above sea-level. The habitat consists of cloud forest that experiences either low or only moderate disturbance. All specimens were found in arboreal bromeliads located between 1.5 - 5.0 m from ground level (Garcia-Castillo et al. 2018).

Life History, Abundance, Activity, and Special Behaviors
All specimens were found in arboreal bromeliads. The bromeliads were located between 1.5 - 5.0 m from ground level and measured 40 - 60 cm in diameter. Since most of the specimens located were juveniles, researchers have not ruled out the possibility that some adults may be found in terrestrial environments under logs or other cover objects (Garcia-Castillo et al. 2018).

Chiropterotriton nubilus was found to co-occur alongside several other plethodontid species, including Aquiloeurycea cafetalera, Parvimolge townsendi, Pseudoeurycea lynchi, and Thorius pennatulus (Garcia-Castillo et al. 2018).

Trends and Threats
Chiropterotriton nubilus has a “Critically Endangered” IUCN Red List threat status because of habitat destruction to wood extraction and expansion of human settlements (IUCN 2020). Additionally, tropical montane cloud forests are among the most threatened ecosystems globally due to deforestation, habitat conversion, and climate change (Toledo-Aceves 2011). The species has also tested positive for Batrachochytrium dendrobatidis (Bd) and is likely susceptible to Batrachochytrium salamandrivorans (Bsal) (IUCN 2020).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Habitat fragmentation
Climate change, increased UVB or increased sensitivity to it, etc.

Comments

PHYLOGENETIC RELATIONSHIPS:

Bayesian Inference of 16s and COI mtDNA showed that C. nubilus is sister to C. chiropterus. Together they are sister to C. aureus (Garcia-Castillo et al. 2018).

ETYMOLOGY:

The species epithet, “nubilus” comes from the Latin word for “cloud”, which refers to the cloud forest that the salamander is found in (Garcia-Castillo et al. 2018).

OTHER INTERESTING INFORMATION:

Veracruz is well known for its high salamander diversity. With the inclusion of C. nubilus, this number has risen to 39 species. The cloud forests of Cofre de Perote alone contains 20 species of the Bolitoglossines super genus, representing 16% of all Mexican salamanders in this tribe. However, that number may increase as phylogenetic relationships become better understood. Researchers suggest that the isolated nature of the cloud forests of Cofre de Perote may have allowed the evolution of so many species of salamanders (Garcia-Castillo et al. 2018).

References

García-Castillo MG, Soto-Pozos ÁF, Aguilar-López JL, Pineda E, Parra-Olea G. (2018). “Two new species of Chiropterotriton (Caudata: Plethodontidae) from central Veracruz, Mexico.” Amphibian and Reptile Conservation 12(2) [Special Section]: 37–54 (e167). [link]

IUCN SSC Amphibian Specialist Group. 2020. “Chiropterotriton nubilus”. The IUCN Red List of Threatened Species 2020: e.T150088962A150088967. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T150088962A150088967.en. Accessed on 22 February 2022.

Toledo-Aceves, T., Meave, J.A., González-Espinosa, M., Ramírez-Marcial, N. (2011). “Tropical montane cloud forests: current threats and opportunities for their conservation and sustainable management in Mexico.” Journal of Environmental Management, 92(3): 974–981. [link]

Species Account Citation: AmphibiaWeb 2022 Chiropterotriton nubilus: Cloud Forest Salamander from Cofre de Perote; Salamandra del Bosque Niebla del Cofre de Perote <https://amphibiaweb.org/species/8951> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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