Eastern Tiger Salamander (Ambystoma tigrinum tigrinum)
The Tiger Salamander, Ambystoma tigrinum covers a wide range of areas extending nearly coast to coast in North America. There are several subspecies within this complex, but some researcehers are of the opinion that the group should be divided into two different species. Previously, even the California Tiger Salamander was considered a subspecies of Ambystoma tigrinum (A. t. californiense), but is now regarded as a separate species, Ambystoma californiense. Of the 6 subspecies of Ambystoma tigrinum discussed here it is the Eastern Tiger Salamander that may some day be regarded as a separate species, in which case it would be given the name Ambystoma tigrinum, while the remaining would be grouped under the name Ambystoma mavortium while retaining the original subspecies name. For example, the Barred Tiger Salamander would then be called Ambystoma mavortium mavortium). The Tiger Salamanders are large, robust salamanders reaching average total lengths up to 8.5 inches, though some individuals over 12 inches long have been found. Outside of the breeding season they are seldom seen, as they spend most of their time underground, often in mammal burrows.
The Eastern Tiger Salamander (Ambystoma tigrinum tigrinum). They are characterized by a dark background with light yellow-gold markings extending down their sides.It is found in the eastern half of North America. In the south it is also a winter breeder, in the north an early spring breeder, migrating to ponds after heavy rains.
Neoteny. Some populations of Tiger Salamanders, particularly in western North America and especially at high altitudes tend to be neotenic. This means that although the salamanders become sexually mature and can reproduce they do not metamorphose, remaining as larvae and breathing with gills. These are sometimes called Axolotls. However, this name is best reserved for Ambystoma mexicanum, a mole salamander species from Mexico that never metamorphoses under natural conditions. Neotenic Tiger Salamanders can become larger than individuals that metamorphose, reaching total lengths of 15 inches.
Tiger Salamander Larvae - external gills distinguish salamander larvae from frog tadpoles (which have internal gills). The legs of the younger (and smaller) larva above left have not yet emerged. In contrast to anurans, the front legs emerge first, then the back. The larva above was found in May, the one below in August.
SOURCE: U.S. Department of the Interior || U.S. Geological Survey
Northern Prairie Wildlife Research Center, 8711 37th St. SE, Jamestown, ND 58401 USA
URL:
http://www.npwrc.usgs.gov/narcam/
