Smallmouth Salamander (Ambystoma texanum)
Alternate names: Small-Mouthed Salamander
Species of Greatest Conservation Need. A valid fishing license is required to possess this species as bait. Relatively common in the southern half of Iowa.
This is a medium Iowa salamander with specimens growing 4-6 inches long. Adults are gray-black to brownish gray in ground color with irregular fleckings of bluish gray or gray on the sides. These markings vary among individuals and among local populations. Some may have a lot of gray reticulation on the sides while others may not. They have a small, blunt head and a small mouth. There is an average of 15 costal grooves. There are four toes on the front and five on the back feet. Larvae have bushy gills and are brown with dark markings on the back. There is also an inconspicuous stripe along the sides. Adult smallmouth salamanders may resemble blue-spotted salamanders, which are very uncommon in Iowa.
There are no subspecies of the smallmouth salamander, Ambystoma texanum.
The smallmouth salamander is found in the southern three tiers of counties in western Iowa and may range as far north as Johnson County in the east (Bailey, 1943).
Smallmouth salamanders are found in wooded habitats with ephemeral ponds, or floodplain in Iowa. Woodlands provide food and shelter in the summer and overwintering sites for overwintering. Shallow pools provide larvae with warm water for faster development and food, and isolate them from fish and other predators requiring deeper water.
Smallmouth salamanders were first reported in 1943 (Bailey 1943) with the first specimen found in 1939. Smallmouth salamanders are secretive and are not often seen. They posses much greater burrowing capabilities compared to the blue-spotted salamander, but are more likely to be found above ground under moist cover in or near woodlands than the tiger salamander. They may be found around the breeding pools hiding under logs and other cover while the earth is moist from spring flooding. During the drier parts of the summer, they remain underground. They occasionally emerge during heavy rains or humid weather. I found adults active on the road at night with high humidity in Fremont County on June 2.
Smallmouths migrate to their breeding pools in March, with or without the aid of spring rains, at night. Males may deposit up to 128 spermatophores during a courtship bout with a single female picking up an average of 26 spermatophores (McWilliams and Bachman, 1988). A female will pick up spermatophores from several males. Females lay eggs sometimes singly or in masses of up to 15 per mass (Petranka 1998). The larvae grow quickly and transform from June through July. Adults overwinter terrestrially in October.
Adults consume insect larvae, earthworms, and other invertebrates. The larvae eat mostly isopods and ostracods.