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Description: Ambystoma bishopi is a moderately sized salamander species. The snout-vent length (SVL) of A. bishopi males ranges from 40.52-47.08 mm.Adult females have an SVL range of 41.09- 51.17 mm. 14 to 16 costal grooves are present. Tail width and height are sexually dimorphic characters, both of which are smaller in males (Pauly et al. 2007). The skin is smooth dorsally and ventrally, but is wrinkled on the flanks between the axilla and groin. The head is elongate. The snout is tapered. The nostrils are small and located towards the tip of the snout. Eyes are of medium size. A groove goes from the corner of the eye to behind the jaw base (Goin 1950).This species has vomerine teeth. However the arrangement and number are debated. Goin (1950) states the teeth are uniformly arranged into two rows while another study claims variable rows of teeth arrangement (Martof and Gerhardt 1965). The forelimbs are stout. The tail is flattened posteriorly and is shorter than the head and body lengths (Goin 1950).
Diagnosis: A. bishopi can be distinguished from A. cingulatum by its shorter limbs and smaller head (USFWS 2009). Generally, this species has fewer costal grooves than A. cingulatum and a shorter tail. The ventral pattern of A. bishopi consists of indistinct white spots on a dark background, creating a "salt and pepper" look, compared to A. cingulatum, which has distinct white spots on the ventral side (Goin 1950; USFWS 2009). The dorsal side pattern of A. bishopi is more net-like in appearance than the frosted patterning of A. cingulatum (USFWS 2009; Goin 1950).
Tadpole morphology: Larvae are less vividly marked and metamorphose earlier and at a smaller size than A. cingulatum (Goin 1950; Telford 1954). A. bishopi has several stripes either yellow brown or black along the body. Gills are bright red in life (Telford 1954).
A. bishopi and A. cingulatum larvae are difficult to distinguish (Martof and Gerhardt 1965). A. cingulatum larvae have broad, striped heads, with a black stripe extending from the nose to the gills and a second stripe along the upper jaw (Palis 1996). A light lateral stripe is retained in first year fully metamorphosed individuals, but is lost in older individuals (Palis 1997).
Coloration: The dorsal surface of A. bishopi is reticulated, with thin grey lines that form a net-like or banded pattern against a black to brown background (USFWS 2009). These lines surround areas of dark coloration (Martof and Gerhardt 1965). Small white flecks on a dark background cover the ventral surface, creating a "salt and pepper" pattern (Goin 1950). Preserved specimens of A. bishopi, can become dark, making their dorsal pattern unrecognizable (Martof and Gerhardt 1965).
Species Authority and Phylogenetic Relationships: A. bishopi was first described by Goin (1950) as Ambystoma cingulatum bishopi. Later this subspecies categorization was refuted by Martof and Gerhardt (1965) and was combined with A. c. cingulatum to form one species, A. cingulatumi. In 2007, A. bishopi was separated from A.cingulatum by Pauly et al. (2007) based on differences in mitochondrial DNA, morphology and allozymes. Because the two species were considered subspecies until 2007 and much of the life history information is assumed to be true for both species (USFWS 2009).