Amphibians
Smallmouth Salamander
Ambystoma texanum · also called smallmouth salamanders
Emerging from an underground burrow on a rainy spring night, a smallmouth salamander migrates toward a temporary woodland pool to breed, part of a genus whose reproductive biology occasionally produces all-female hybrid lineages nearly as strange as the parthenogenetic whiptail lizards of the desert Southwest.
Overview
The smallmouth salamander, Ambystoma texanum, is a lungless amphibian native to forest and wetland-edge habitat across a broad range of the central and eastern United States. Its distinctively proportioned small mouth, involvement in unusual all-female hybrid salamander lineages, and dependence on temporary, fishless woodland pools for breeding make it one of the more reproductively fascinating members of the mole salamander group.
A salamander tangled up in cloning
Beyond its subtly small mouth, the smallmouth salamander is best known among biologists for its role in an unusual all-female hybrid reproductive system, a genetic arrangement that keeps the species tangled up with its close relatives in ways few other amphibians experience.
Status
Least Concern — widespread and common across suitable forest and wetland-edge habitat throughout the central and eastern United States.
Smallmouth Salamander: common questions
Why is it called the smallmouth salamander?
This species has a comparatively small mouth relative to the overall size of its head, a proportion distinctive enough compared with other mole salamanders to give the species its common name, even though the difference is subtle enough that it is most easily noticed when directly compared with a close relative.
What is unusual about the smallmouth salamander's reproduction?
This species is one of several mole salamander relatives involved in forming unusual all-female hybrid lineages, which take genetic material from males of related species without fully incorporating it into normal sexual reproduction, an arrangement that produces genetically distinctive, largely clonal populations found in very few other vertebrate groups.
Why does the smallmouth salamander breed in temporary pools?
This species breeds in shallow, temporary woodland pools, conditions that tend to stay fishless since the water does not persist long enough to support fish populations, giving eggs and developing larvae a better chance of survival than they would have in a permanent pond containing fish predators.
How much time does the smallmouth salamander spend above ground?
This species spends the great majority of the year hidden underground in burrows, emerging mainly during the breeding season to migrate toward the temporary woodland pools it depends on for reproduction, spending comparatively little time visible on the surface overall.