|
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
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)
Citation: AmphibiaWeb: Information on
amphibian biology and conservation. [web application]. 2013. Berkeley, California:
AmphibiaWeb.
Available: http://amphibiaweb.org/.
(Accessed: May 18, 2013).
AmphibiaWeb's policy on data use.
|
Raffaëlli Account