AMPHIBIAWEB
Ambystoma taylori
Taylor’s salamander
Subgenus: Heterotriton
family: Ambystomatidae

© 2014 Dr. Joachim Nerz (1 of 10)
Conservation Status (definitions)
IUCN (Red List) Status Critically Endangered (CR)
CITES No CITES Listing
Other International Status None
National Status Category Pr (Special protection)
Regional Status None

 

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Description
Ambystoma taylori is a facultative paedomorph, but complete metamorphosis has only been observed in laboratory specimens, which also showed highly reduced fitness. The salamanders become reproductively mature when they reach a snout to vent length of about 70 mm. Paedomorphic adults usually grow to an average of 76 mm from snout to vent, with a range of about 60 – 113 mm (Brandon et al. 1982).

The head of adult A. taylori is large, wide, and almost triangular in shape. It is slightly longer than wide. Paedomorphic adults retain three pairs of fimbriae-lined external gills with 19 – 26 gill rakers. The species has 14 - 16 trunk vertebrae and 13 or more costal grooves. The tail is approximately three-fourths the snout-vent length. There is a visible dorsal body fin with a wide fleshy base that extends from the base of the head to the tail. It is widest at the base of the head and narrows as it extends onto the tail. All limbs are fully developed, yet appear slightly reduced as in most neotenic species. When adpressed along the sides, the limbs overlap by 3 – 4 intercostal folds. Mature adults have short digits that are more cone-shaped. The toes are broad at the base and flattened. Additionally, they have dark keratinized, nail-like tips and lack flat edges. There are prominent tubercles on the inner and outer metacarpals and on the metatarsals. Immature and young adult individuals have toes that are triangular and flattened with fringed sides (Brandon et al. 1982).

Metamorphosed adults' tail and body fins were reabsorbed, gills were reabsorbed and stubs completely lost, eyelids formed, and toes became more elongated and narrow. The typical osteology changes also occurred. However, the carpals and tarsals did not ossify (Brandon et al. 1982).

When larvae hatch, they are typically 10 – 17 mm in length and have 13 - 24 gill rakers on the anterior side of the third gill arch (Gehlbach 1967).

Ambystoma taylori has 19 - 26 gill rakers on the third gill arch, unlike A. tigrinum, its morphologically closest relative, which has 27 - 37 gill rakers. The dorsal fin has a wide, raised, soft base, which is thicker and longer than in other Ambystoma species and runs down the length of the body. This base is widest behind the head due to deposits of adipose tissue. The vomerine teeth of A. taylori align in one row and run anterior to posterior, as opposed to the patches of vomerine teeth in A. tigrinum, which lay in the front of the mouth. The focal species can also be differentiated by having 14 - 16 trunk vertebrae and 13 or more costal grooves. When adpressed, there is an overlap of limbs that is three to five intercostal folds in length. Ambystoma taylori is described as having a brighter yellow coloring than A. tigrinum. In metamorphosed adult A. taylori, the carpals and tarsals never fully ossified, unlike completely metamorphosed A. tigrinum specimen. Other species of Ambystoma can be differentiate based on geographic range (Brandon et al. 1982).

In life, both branchiate adults and metamorphosed adults have dorsums that are various hues of yellow: golden, canary yellow, pale yellow, or subdue yellowish tan. They have numerous 1 – 3 mm round, maroon spots dominating their dorsal side including their tail and trunk, as well as the sides of their head. In metamorphosed adults, the spots merge to form a more mottled pattern. The dorsal surfaces of the legs have spots that merge into a more mottled pattern. Their ventral surface is also pale yellow but covered in spots that are darker in color and appear closer to mottling, especially near the throat and pectoral region. There is a spotless patch of skin posterior to the gular fold (Brandon et al. 1982).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico

 

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Ambystoma taylori is endemic to Laguna Alchichica in Puebla, Mexico. This lake has a high salinity, 8.2 - 8.3%, and lies in an otherwise arid environment (Brandon et al. 1982). The lake sits at an elevation of 2,320 meters above sea level (Caballero et al. 2003). Taylor salamanders have been found at various level of depth in the water as deep as 12 m. Ambystoma taylori is the only known amphibian species in this lake, while several squamate species have been found in the surrounding area (Camarillo 1998).

Life History, Abundance, Activity, and Special Behaviors
During an underwater scuba survey of Laguna Alchichica, it was observed that A. taylori were more abundant at greater depths. When not feeding at the shore, salamanders could be identified easily 4 - 12 m below the surface. At 12 m below, according to field observations, there were significantly more individuals. They also observed that individuals at greater depths appeared to be larger, although the observation was never tested. There is a hypothesized difference in nocturnal activity between the sexes in that of all indexed A. taylori specimen collected from the wild, the ratio of females to males was 2.4:1. This could indicate that females are more active feeders at night, and therefore more likely to be found on the shore during night collections (Brandon et al. 1982).

When disturbed, they swim 3 – 4 m away and bury themselves in sediment or press themselves tightly against rock crevices (Brandon et al. 1982).

Little is known about the life history of A. taylori, however assumptions can be made based on accounts and descriptions of closely related species including, but not limited to, A. tigrinum, A. mexicanum, A. dumerilii, A. ordinarium, and A. velasci (Shaffer 1984, Shaffer and McKnight 1996).

Courtship behaviors have been observed in many Ambystomatid species and are often very similar between closely related species. In A. tigrinum, the males will rub their nose on the female’s sides and bellies, often balancing her on his nose and pushing her in different directions. Eventually he will swim ahead of her and spread his limbs out and upwards, and lift his tail to deposit a spermatophore on the ground. The female then places her nose next to his cloaca and follows him forward until her cloaca is directly over the spermatophore and then she retracts it into her vent to fertilize her eggs (Kumpf 1934).

In A. tigrinum nebulosum, females choose small pebbles, twigs and aquatic plants that are close to the ground as their oviposition sites. Eggs are laid individually, but can sometimes be close enough in proximity to be considered a cluster. After choosing a pebble or twig upon which to lay the eggs, the female will grasp the object with her hind limbs and rub her cloaca on the object while keeping her tail upright and swinging it back and forth for a few moments, then remain motionless until the egg is properly placed (Hamilton 1948). In A. tigrinum, eggs are typically 2 - 5 mm in diameter and contain three envelopes (Gehlbach 1967). Parental care is not observed in A. tigrinum (Nussbaum 1985).

Direct observation of ova in the A. taylori holotype revealed hundreds of oocytes that were 0.3 – 0.5 mm in diameter and pale in color.

Feeding mechanisms were examined and compared between A. dumerilii, A. mexicanum, and A. ordinarium. All three species elevate their heads at similar heights and angles to capture prey and rely on suction feeding through the hyoid to capture aquatic prey. The extent of hyoid depression is positively correlated with the size of the head in the adults, which means that prey type and size depends on the size of the head (Shaffer and Lauder 1985). Prey includes aquatic invertebrates and eggs of other salamanders.

Trends and Threats
Ambystoma taylori is vulnerable to contamination or alteration of Laguna Alchichica (Camarillo 1998). Pollution, exotic species, and deforestation are all threats to mole salamander species in general in Mexico. The Trans-Mexican Volcanic Belt, which includes A. taylori’s range, is an especially disturbed area due to high urbanization (Heredia-Bobadilla et al. 2016).

Redirection of water for human consumption and agriculture reduce the amount of water in the lake and cause the salinity to increase. Even though this salamander has a high tolerance for salinity, their eggs are especially sensitive to salinity concentrations because they have a lower tolerance than the adults (IUCN 2015).

Though it has not been found in A. taylori, Batrachochytrium dendrobatidis fungus has been detected in several other Ambystoma species in Mexico and could pose a risk (Frías-Alvarez et al. 2008).

Relation to Humans
Some of these salamanders were harvested by a small fishery in the 1990s (Camarillo 1998). As stated above, water use from Lake Alchichica has increased its salinity and caused the habitat quality to decline.

Possible reasons for amphibian decline

General habitat alteration and loss
Urbanization
Prolonged drought
Drainage of habitat
Local pesticides, fertilizers, and pollutants
Climate change, increased UVB or increased sensitivity to it, etc.

Comments
The species authority is: Brandon, R.A., Maruska, E.J. and Rumph, W.T. (1982). “A new species of neotenic Ambystoma (Amphibia, Caudata) endemic to Laguna Alchichica, Puebla, Mexico.” Bulletin Southern California Academy of Sciences 80, 3: 112-125.

Starch gel electrophoresis was used to determine the relationship between the Mexican Ambystomatid salamanders and determined that A. taylori is closely related to A. tigrinum, A. mexicanum, A. dumerilii, and A. ordinarium (Shaffer 1984). Further research on mtDNA determined that A. taylori is also very closely related to A. velasci populations in the eastern Mexican Plateau (Shaffer and McKnight 1996). They are part of a larger complex of tiger salamanders (Ambystoma) in North America that have little genetic variation, suggesting recent derivation of the species. There are 18 known Ambystoma species in Mexico, 16 of which are endemic (Heredia-Bobadilla et al. 2016).

This species got its name from herpetologist Edward H. Taylor who originally collected a sample of A. taylori in 1943.

Edward H. Taylor collected the first specimen of A. taylori, but misidentified it as the larval form of a new species, A. subsalsum, which he described. In the 1970’s researchers began to suspect that the metamorphed holotype of A. subsalsum was actually a specimen of A. tigrinum. Then in May 1980, it was confirmed that larval and adult A. tigrinum were in the area from which the holotype was collected and that the holotype of A. subsalsum was a specimen of A. tigrinum. The researchers then investigated the larval specimens that were identified as A. subsalsum and discovered it was a unique species that they named A. taylori (Brandon et al. 1982).

In every case of complete maturation, the laboratory specimen died from starvation. Ambystoma taylori performs better in a paedomorphic state and seems to require a saline habitat. During metamorphosis, the individuals decreased or completely stopped eating, leading to their deaths (Brandon et al. 1982).

References

Brandon, R.A., Maruska, E.J., Rumph, W.T. (1982). ''A new species of neotenic Ambystoma (Amphibia, Caudata) endemic to Laguna Alchichica, Puebla, Mexico.'' Bulletin Southern California Academy of Sciences, 80(3), 112-125.

Caballero, M., Vilaclara, G., Rodríguez, A., Juárez, D. (2003). ''Short-term climatic change in lake sediments from lake Alchichica, Oriental, Mexico.'' Geofísica Internacional , 42(3), 529-538.

Camarillo, J.L. (1998). ''Observaciones preliminares sobre los anfibios y reptiles de los lagos cráter de Puebla-Veracruz.'' Anales del Instituto de Biologia Universidad Nacional Autonoma de México Serie Zoología, 69(1), 125-127.

Frías-Alvarez, P., Vredenburg, V. T., Familiar-López, M., Longcore, J. E., González-Bernal, E., Santos-Barrera, G., Zambrano, L., and Parra-Olea, G. (2008). ''Chytridiomycosis survey in wild and captive Mexican amphibians.'' EcoHealth, 5, 18-26.

Gehlbach, F.R. (1967). ''Ambystoma tigrinum (Green) Tiger Salamander.'' ,

Hamilton, R. (1948). ''The egg-laying process in the tiger salamander.'' Copeia, 1948(3), 212-213.

Heredia-Bobadilla, R.L., Monroy-Vilchis, O, Zarco-Gonzalez M.M., Martinez-Gomez, D., Mendoza-Martinez, G.D., Sunny, A. (2016). ''Genetic structure and diversity in an isolated population of an endemic mole salamander (Ambystoma rivulare Taylor, 1940) of central Mexico.'' Genetica, 144(6), 689-698.

IUCN SSC Amphibian Specialist Group. (2015). Ambystoma taylori. The IUCN Red List of Threatened Species 2015: e.T59070A53974679. http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T59070A53974679.en. Downloaded on 19 November 2015.

Kumpf, K.F. (1934). ''The courtship of Ambystoma tigrinum.'' Copeia, 1934(1), 7-10.

Nussbaum, R. A. (1985). . Museum of Zoology, University of Michigan, Ann Arbor.

Shaffer, H. B., and McKnight, M. L. (1996). ''The polytypic species revisited: genetic differentiation and molecular phylogenetics of the Tiger Salamander Ambystoma tigrinum (Amphibia: Caudata) complex.'' Evolution, 50, 417-433.

Shaffer, H.B. (1984). ''Evolution in a paedomorphic lineage. I. An electrophoretic analysis of the Mexican Ambystomatid salamanders.'' Evolution, 38(6), 1194-1206.

Shaffer, H.B., Lauder, G.V. (1985). ''Patterns of variation in aquatic ambystomatid salamanders: kinematics of the feeding mechanism.'' Evolution, 39(1), 83-92.



Written by Rae Purington, Hanika Cook, and Annabelle Louderback (rpurington AT ucdavis.edu, hrcook AT ucdavis.edu, ahlouderback AT ucdavis.edu), University of California Davis
First submitted 2018-01-18
Edited by Ann T. Chang (2018-02-06)

Species Account Citation: AmphibiaWeb 2018 Ambystoma taylori: Taylor’s salamander <http://amphibiaweb.org/species/3848> University of California, Berkeley, CA, USA. Accessed Dec 12, 2018.



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Citation: AmphibiaWeb. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 12 Dec 2018.

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