AMPHIBIAWEB
Ambystoma dumerilii

Subgenus: Heterotriton
family: Ambystomatidae

View distribution map using BerkeleyMapper.


Conservation Status (definitions)
IUCN (Red List) Status Critically Endangered (CR)
See IUCN account.
CITES Appendix II
Other International Status None
National Status None
Regional Status None

   

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Description
The species (which has frequently been placed in Bathysiredon or Siredon) is a neotenic salamander resembling the Mexican axolotl (A. mexicanum). This animal is tan to brown and homogenous in coloration. Distinct features include a flat, wide head, caudal fins, and few rakers on the third gill arch’s anterior surface (the exact amount is disputed). The salamander can also be identified by perennibranchiate (lifelong), hyperfilamentous gills and diminutive, webbed toes with the fourth digit possessing three phalanges (Brandon, 1992, Smith, 1948). A sexually mature specimen measures, from snout to vent, over 122 mm; there is no body length difference between the sexes. Of preserved specimens, total size ranges from 128-282 mm (Brandon, 1970).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico

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The amphibian is known historically and currently to inhabit only Lake Patzcuaro in the Mexican state of Michoacan (Brandon, 1970). Rumors of salamander sightings in San Juan del Rio, Queretaro, are highly unlikely due to geographic isolation. Area of occurrence is less than 100km2, the occupancy area less than 10km2 (IUCN).

Life History, Abundance, Activity, and Special Behaviors
Metamorphosis in nature has not been observed although roughly a third of both wild-caught and first generation laboratory animals undergo the process according to research conducted at Carbondale, Illinois (Brandon, 1976). Hybrids between dumerilii and possible relatives such as mexicanum and tigrinum are also prone to metamorphose (Brandon, 1977). Spontaneous transformations generally occur during breeding seasons, suggesting a hormonal association. Adult animals do not experience periodic ecdysis (molting), but continuously shed the stratum corneum (exterior skin). The transformed skin does not include Leydig and mucous cells like normal adult amphibian skin. An incomplete metamorphosis over a period up to three years indicates that the change is unnatural for the species; no spontaneously transformed animal lived over five months and no induced transformed animal lived over 48 days from the beginning of morph (Brandon, 1976).

Based solely on the historical vs. present numbers reported by local fishermen, wild populations have diminished dramatically (IUCN).

Ova mature during the rainy seasons and spawning occurs with increasing atmospheric temperatures; breeding observed during winter (IUCN) and spring (Brandon, 1970).

Salamanders feed by suction and sport distinguishably few “tooth-like rakers” as described above (IUCN) - laboratory animals thrive on beef liver (Brandon, 1970).

Trends and Threats
It was feared in the 1930’s that the introduction of largemouth bass would decimate amphibian colonies, however, no salamander decline was recorded to have been directly attributed to the foreign fish (Brandon, 1970). Argulus ambystoma, a new species of parasitic crustaceans (fish lice) found on fish, a crayfish, and the dumerilii of Lake Patzcuaro, resides on the skin surface and retreats to the gills of hosts upon exposure to light; its threat to A. dumerilii is unknown (Poly, 2003).

Relation to Humans
Known locally as Achoque, the species is harvested by the indigenous Tarascan people for consumption and for its believed medicinal properties as a respiratory remedy (IUCN).

Possible reasons for amphibian decline

General habitat alteration and loss
Intentional mortality (over-harvesting, pet trade or collecting)

Comments

References

Brandon, R.A. 1970. Size range maturity, and reproduction of Ambystoma (bathysiredon) dumerilii (Dugès), a paedogenetic Mexican salamander endemic to Lake Pátzcuaro, Michoacán. Copeia 1970: 385-388.

Brandon, R.A. 1976. Spontaneous and induced metamorphosis of Ambystoma dumerilii (Dugès), a paedogenetic Mexican salamander, under laboratory conditions. Herpetologica 32: 429-438.

Brandon, R.A. 1977. Interspecific hybridization among Mexican and United States salamanders of the genus Ambystoma under laboratory conditions. Herpetologica 33: 133-152

Brandon, R.A. 1992. Ambystoma dumerilii. Catalogue of American Amphibians and Reptiles 532: 1-3.

Poly, W.J. 2003. Argulus ambystoma, a new species parasitic on the salamander Ambystoma duerilii from Mexico (Crustacea: Branchiura: Argulidae). Ohio Journal of Science 103: 52-61

Smith, H.M. Taylor, E. 1948. An Annotated Checklist and Key to the Amphibia of Mexico. Smithsonian Institution Bulletin 194: 1-118





Written by Sharon Liu (sharonliu AT berkeley.edu), UC Berkeley
First submitted 2007-06-27
Edited by David Wake; Tate Tunstall (2010-09-22)



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Citation: AmphibiaWeb: Information on amphibian biology and conservation. [web application]. 2014. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. (Accessed: Sep 2, 2014).

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