Description
Ambystoma altamirani is a species of salamander that grows to a modest 9.3 cm in snout-vent length, the males of which attain larger sizes than the females. The flattened head of this species is wider than the neck and body, possesses a well defined neck fold, and holds small, dorsolaterally positioned eyes. Their snout is slightly squared off and narrow with the nostrils being directed towards the sides. Their lips are plump to the point where they limit the mouth’s range of movement (Dúges 1895). The adults retain larval features as they metamorphosize (partial paedomorphosis because of cold mountain stream habitat) such as their aforementioned lips, small maxillae and delayed tooth features (Reilly and Brandon 1994). The body is short and has 12 costal grooves, with a comparatively long tail that begins rounded but becomes compressed towards the tip. The males have longer tails than females (Raffaëlli 2022).

DIAGNOSIS:

Ambystoma altamirani are longer, more slender, and have longer tail and limb proportions than A. rivulare, as well as having a different head shape (Taylor 1940). Additionally, A. altamirani have a generally lighter coloration than A. rivulare (Raffaëlli 2022). Ambystoma altamirani are smaller than A. leorae (with the latter reaching snout-vent sizes up to 10.3 cm). Despite these slight differences, A. altamirani is best identified by range as they do not co-occur with the previously mentioned species.

COLORATION:

In life, A. altamirani are black, brownish or gray with black markings dorsally, with the underside being yellowish or slate colored (Dúges 1895). Their markings are a combination of dark spots and yellowish blotches present dorsally with the underside consisting of light spots.

VARIATION:

The most common color variations are olive-green with black markings, uniform black, black with yellow markings and olive-green with black and yellow markings (Villarreal Hernández et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (96 records).

Ambystoma altamirani are native to the mountains of the State of Mexico, Distrito Federal, and Morelos, Mexico in the Mexican Plateau of the Trans-Mexican Volcanic Belt (Woolrich-Piña et al. 2017). They are found at 2,450 - 3,487 m above sea level near permanent streams in forests composed of trees like Pinus hartwegii and Abies religiosa (Lemos-Espinal et al. 2016). They have also been found in streams in landscaped park areas with managed grass (Campbell and Simmons 1962).

Life History, Abundance, Activity, and Special Behaviors
Ambystoma. altamirani increase in abundance when certain microhabitat preferences are met, such as when streams are wider with more water volume, muddy and dark colored substrates are present and an abundance of emergent aquatic vegetation. They prefer cold and well oxygenated water with temperatures from 5 - 15.2 °C., with a variety of fast flowing and slow moving pools present. The adults can also be found under rocks and logs near the water (Franco et al. 2022). Despite their complex habitat preferences, they seem to be relatively hardy; for example, an individual was found active and healthy at the muddy bottom of a frozen stream during freezing conditions (Sánchez-Sánchez et al. 2022).

Breeding for A. altamirani takes place throughout the year, with 15 - 23 egg masses being laid on aquatic plants or on the undersides of rocks and are connected through a strand of jelly. These eggs are often laid in June (Campbell and Simmons 1962). After hatching, the larvae metamorphosize in roughly 6 months at around 48 - 70 mm in snout-vent length throughout the year (Lemos-Espinal et al. 2016). However, this species is known to sometimes be paedomorphic (Everson et al. 2021).

The adults are usually aquatic, but stay near their stream habitat even out of the water (Dúges 1895). Their affinity for staying in the water is likely the cause for the paedomorphosis of their teeth and cranial morphology to help retain the larval ability to suction feed. However, this means they have trouble feeding on land (Reilly and Brandon 1994). When in water, they are usually active near the surface and are most commonly observed/active in June/July. Ambystoma altimirani usually stick to the streams they are in, not migrating very often, usually only if the surface conditions are suitable (e.g. forest and proper moisture so as to not be exposed to predators). However, this doesn’t affect their genetics very much as only 1 - 10 individuals are likely needed to migrate between populations to keep up genetic variability and prevent inbreeding (Heredia-Bobadilla et al. 2017). Franco et al. (2022) found that the species is affected more by aquatic factors than terrestrial factors, such as a stream's proximity to livestock or tree cover.

The different color variations of A. altamirani are associated with some other environmental factor other than the color of the substrate as both light and dark individuals prefer dark substrates (Villarreal Hernández et al. 2020). However, the larvae of this species prefer darker substrates than the adults, suggesting there could be an ontogenetic shift in substrate color use.

Ambystoma altamirani are predated by species such as Thamnophis scaliger (Villarreal Hernández et al. 2019). They are also known to have been infested with leeches (Placobdella cf. mexicana) that can significantly reduce their body mass, possibly leading to death if they are infested with enough individuals. Adult bivalves of the family Sphaeriidae have also been found to infest this species (Hernández-Luría et al. 2023).

Larva
The larvae of this species range in size from 35 - 63 mm in snout-vent length. They metamorphosize in roughly 6 months at around 48 - 70 mm in snout-vent length (Campbell and Simmons 1962, Lemos-Espinal et al. 2016).

Their coloration consists of a blackish background with yellow and black spots and blotches, though the coloration changes as larvae grow, with smaller individuals having coloration more restricted into ‘bands’ while older individuals' coloration overall being ‘looser (Campbell and Simmons 1962). Larvae are variable in coloration, with full yellow, green and gray variants being found. Many different colorations can be seen in one population (Villarreal Hernández et al. 2020). The ventral coloration changes from yellow to pink as they age as well (Campbell and Simmons 1962).

The larvae feed primarily on ostracods and gastropods, the former being more common in streams lacking human disturbance (Lemos-Espinal et al. 2015). Considering this narrow diet range and limited food availability, undisturbed streams that promote their prey items are important for larval abundance.

Trends and Threats
Ambystoma altamirani is greatly affected by many modern conservation issues due to their distribution being right next to the largest city in North America, Mexico City. The expansion of this city leads to factors like habitat destruction/alteration through pollution, logging, urbanization, etc. Introduced fish like Oncorhynchus mykiss also affect this species, as Ambystoma altamirani have been found to be absent from all streams that contain Oncorhynchus mykiss, likely due to how the fish eat larval salamanders and compete with adults and larvae for food (Estrella-Zamora et al. 2018). Even populations in streams previously inhabited by A. altamirani were found to likely be extirpated by the introduction of trout (Guerrero de la Paz et al. 2020). Individuals from this species have also been found to be infected with Batrachochytrium dendrobatidis. All of these factors threaten the small and isolated distribution and habitat of A. altamirani, which could also jeopardize gene flow due to a lack of genetic connectivity and bottlenecks combined with their specific microhabitat affinities (Heredia-Bobadilla et al. 2017).

Relation to Humans
Humans have been known to eat species of Ambystoma including A. altamirani (Heredia-Bobadilla et al. 2017).

Comments

PHYLOGENETIC RELATIONSHIPS:

Ambystoma altamirani was previously contained within the genus Rhyacosireon with A. rivulare and A. leorae (Woolrich-Piña et al. 2017). However, Reilly and Brandon (1994) dismissed Rhyacosiredon as a valid genus because the original diagnosing characters weren’t valid or were shared with other species of Ambystoma. Additionally, species previously included in ‘Rhyacosiredon’ have been known to be able to produce viable hybrids with species like A. dumerilii, A. andersoni and A. ordinarium. According to a contested Bayesian and maximum likelihood analysis of 92 concatenated nuclear loci done by Everson et al. (2021), populations of A. altamirani, A. leorae and A. rivulare are likely admixed and not reproductively isolated enough to be considered different species, and should all be group under the oldest name: A. altamirani, with the sister of A. altamirani being A. leorae. This species also contains A. zempoalaensis, a briefly recognized lake dwelling population of A. altamirani (Reilly and Brandon 1994).

OTHER INTERESTING INFORMATION:

References
Campbell, H. W., and Simmons, R. S. (1962). Notes on the eggs and larvae of Rhyacosiredon altamirani (Dugès). Herpetologica, 18(2), 131-133. [link]

Dugès, A. A. D. 1895. Description d’un Axolotl des Montagnes de las Cruces (Amblystoma altamirani, A. Dugès). México: Institut Médico-Nacional, Imprimèrie du Ministère de Fomento. [link]

Everson, K. M., Gray, L. N., Jones, A. G., Lawrence, N. M., Foley, M. E., Sovacool, K. L., Kratovil, J. D., Hotaling, S., Hime, P. M., Storfer, A., Parra-Olea, G., Percino-Daniel, R., Aguilar-Miguel, X., O’Neill, E. M., Zambrano, L., Shaffer, H. B., and Weisrock, D. W. (2021). Geography is more important than life history in the recent diversification of the Tiger Salamander Complex. Proceedings of the National Academy of Sciences, 118(17), e2014719118. [link]

Franco, W. G., Smith, G. R., and Lemos-Espinal, J. A. (2022). The effects of livestock, proximity to trees, and aquatic characteristics on the abundance of Ambystoma Altamirani within a stream. Journal of Herpetology, 56(1), 56-59 . [link]

Guerrero de la Paz, J. G., Mercado-Silva, N., Alcalá, R. E., and Zambrano, L. (2020). Signals of decline of flagship species Ambystoma Altamirani dugès, 1895 (Caudata, Ambystomatidae) in a Mexican natural protected area. Herpetozoa, 33, 177–183. [link]

Heredia-Bobadilla, R.-L., Monroy-Vilchis, O., Zarco-González, M. M., Martínez-Gómez, D., Mendoza-Martínez, G. D., and Sunny, A. (2017). Genetic variability and structure of an isolated population of Ambystoma Altamirani, a mole salamander that lives in the mountains of one of the largest urban areas in the world. Journal of Genetics, 96(6), 873–883. [link]

Hernández-Luría, J., Méndez-Méndez, O., Sánchez-Sánchez, R., Smith, G. R., and Lemos-Espinal, J. A. (2023). Observations of two invertebrate parasites on Ambystoma altamirani (Caudata: Ambystomatidae) from the Sierra de Las Cruces, Mexico. Phyllomedusa, 22(1), 37–42. [link]

Hernández, V. V., Smith, G. R., Ayala, R. M., and Lemos-Espinal, J. A. (2020). The relationship between body and substrate color for Ambystoma altamirani (Caudata: Ambystomatidae) from the Arroyo Los Axolotes, Mexico. Phyllomedusa, 19(2), 243–251. [link]

Hernández, V. V., Lemos-Espinal, J. A., Smith, G. R., and Montoya-Ayala, R. (2020). Natural history observations of Ambystoma altamirani and Dryophytes plicatus at Sierra de las Cruces, State of México, Mexico. The Southwestern Naturalist, 64(2), pp. 135-137. [link]

Lemos-Espinal, J. A., Smith, G. R., Hernández Ruiz, Á., and Montoya Ayala, R. (2016). Stream use and population characteristics of the endangered salamander, Ambystoma altamirani, from the Arroyo los Axolotes, State of México, Mexico. The Southwestern Naturalist, 61(1), pp. 28-32. [link]

Lemos-Espinal, J. A., Smith, G. R., and Woolrich-Piña, G. A. (2015). Diet of larval Ambystoma altamiranoi from Llano de los Axolotes, Mexico. Current Herpetology, 34(1), 75–79. [link]

Raffaëlli, J. (2022). Salamanders & Newts of the world. Penclen Edition.

Reilly, S. M., and R. A. Brandon. 1994. Partial paedomorphosis in the Mexican stream ambystomatids and the taxonomic status of the genus Rhyacosiredon Dunn. Copeia 1994, 656–662. [link]

Sánchez-Sánchez, R., Méndez-Méndez, O., Smith, G. R., Montoya- Ayala, R., Woolrich-Piña, G., and Lemos-Espinal, J. A. (2022). Field observations of Ambystoma altamirani at near-freezing conditions in the Sierra de Las Cruces, Mexico. Phyllomedusa, 21(1), 67–69. [link]

Taylor, E. H. (1940). A New Rhyacosiredon (Caudata) from Western Mexico. Herpetologica, 1(7), 171-176. [link]

Woolrich-Piña, G., Smith, G. R., Lemos-Espinal, J. A., Zamora, A. B., and Montoya Ayala, R. (2017). Observed localities for three endangered, endemic Mexican ambystomatids (Ambystoma altamirani, A. leorae, and A. rivulare) from central Mexico. The Herpetological Bulletin, 139, 12-15. [link]

Zamora, A. B., Smith, G. R., Lemos-Espinal, J. A., Woolrich-Piña, G. A., and Ayala, R. M. (2018). Effects of nonnative rainbow trout on two species of endemic Mexican amphibians. Freshwater Science, 37(2), 389–396. [link]

Species Account Citation: AmphibiaWeb 2024 Ambystoma altamirani: Mountain Stream Siredon <https://amphibiaweb.org/species/3826> University of California, Berkeley, CA, USA. Accessed Nov 13, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 13 Nov 2024.

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