Ambystoma annulatum has a slender girth, well-rounded body and, among salamanders, a generally small head and long tail. Adults grow to a range of 140-180 mm snout-vent length, with a record length of 255 mm. A. annulatum usually has 15 costal grooves (Behler 1996). Dorsally, adults range from dark grey to blackish brown. This is contrasted by white to yellowish and broken bands covering the entire body, from snout to tail. Ventrally, the color varies from light grey to yellowish, peppered with light-colored spots. There is typically a short, light colored bar between the eyes that may continue below the eyes to point diagonally posterior. Recently metamorphosed juveniles have a drab green to dark grey dorsal surface, and a row of dorsolateral yellowish spots extending from the front limbs to the tip of the tail. Laterally, a broad band runs from the gills two-thirds of the way down the tail, which lacks pigmentation. Bellies are greyish-yellow. Juveniles develop the blotches or rings that characterize this species (annulatum = annulated, ringed (Beltz 2002) )approximately two months after metamorphosis (Petranka 1998). The sexes are monomorphic and it is unknown whether there is any geographic or seasonal variation (Bishop 1962; Johnson 1977; Petranka 1998). A. annulatum has a depressed snout that is evenly and bluntly rounded. Its teeth, found on the vomer bone, are arrayed in two short series located entirely behind the nares. Each series consists of about 7-11 small, blunt teeth (Bishop 1962). Each hind foot has five toes (Bishop 1962).