The Blue-spotted Salamander attains a length as an adult between 4 and 5.5 inches. It is found in moist wooded areas under debris such as rotting logs, vegetation and loose soil. The spotting is generally light blue or white on a dark blue to black background, and the belly is also dark. The Jefferson Salamander is the only salamander that could be confused with the Blue-spotted by virtue of it also having blue spots, but the Jefferson Salamander's spots are generally small flecks. The Jefferson Salamander also has a paler background color and light colored belly versus the dark blue/black background color of the Blue-spotted. These two species hybridize in the parts of their ranges that overlap making identification in these areas difficult.
compare distribution maps at:
http://www.npwrc.usgs.gov/narcam/idguide/ambylat.htm
Hybrids tend to reach larger sizes than the Blue-spotted Salamander and have a paler background closer to the Jefferson Salamander. Within hydrid zones check the vent - this is surrounded by black in the Blue-spotted and gray in the Jefferson.
SOURCE: U.S. Department of the Interior || U.S. Geological Survey
Northern Prairie Wildlife Research Center, 8711 37th St. SE, Jamestown, ND 58401 USA
URL:
http://www.npwrc.usgs.gov/narcam/