Comprehensive DescriptionRead full entry
Ambystoma andersoni is a pedomorphic species of Tiger Salamanders with adult male and females snout-vent length range from 100 to140 mm, 14 to 25 gill rakers on the anterior face of the third gill arch, and a short tail that is 56-78% of snout-vent length. The two sexes do not show sexual dimorphism in body proportions or in number of teeth. This species presents 14 costal grooves, 15 trunk vertebrae, 103 premaxillary/maxillary teeth, 35-38 vomerine teeth, and 19-16 palatine teeth. Toes are flattened and extensively webbed, extending nearly half the length of digits and two-thirds on hind feet. The posterior margin of hind foot conspicuously keeled and there are three rather than four phalanges in the fourth hind toe (Krebs and Brandon 1984).
Similar species include A. dumerilii, which also has short, highly webbed toes and 14 - 25 gill rackers, but A. andersoni is reddish-brown with spotting while A. dumerilii is uniformly brown with no markings. The two species also differ in A. dumerilii having hyperfilamentous gills, a smaller eye, smaller eggs, and larger body size at sexual maturity (Krebs and Brandon 1984).
In life, the body is reddish-brown marked with black dots that are sometimes interconnected, The dorsal coloring is reddish-brown even in preservative (Krebs and Brandon 1984).
The species authorities are Krebs and Brandon (1984).