(Notophthalmus viridens louisianensis)
Pictured above: This individual was brought to me by a trapper in nearby Trempeleau County (WI) and I believe this is the terrestrial adult phase of this species. Its color is dark dorsally, however, its' tail appears to be wide, as if still used for swimming (right). It is possible that this individual was in the process of transforming from an aquatic to a terrestrial phase when captured.
Description: The Central Newt is a relatively small amphibian, reaching adult lengths of 2.5 to 4 inches. What is most interesting about these amphibians is that there are three phases, which represent three different life stages: the aquatic adult stage, the terrestrial adult stage, and the terrestrial juvenile stage (or red eft). Aquatic adults are relatively smooth skinned, and beige or olive in color. Occasionally, they will have lighter spots present dorsally. They are normally light beige ventrally. The terrestrial adult is generally more rough-skinned and very dark in coloration. Ventrally, they can be whitish with black flecks. The terrestrial juvenile, or red eft, stage (as the name implies) is primarily orange-red with tiny black flecks. Central Newts are members of the family Salamandridae.
Habitat/Ecology: Central Newts are said to be fond of semi-permanent ponds in heavily vegetated forests. They have also been encountered in roadside ditches and river backwaters. As terrestrial adults or juveniles, newts will hide and/or overwinter under ample vegetative debris (i.e., leaf litter, bark).
In their terrestrial phase, they consume primarily small invertebrates, such as insect, slugs, and worms. In their aquatic phase, they will eat zooplankton, oligochaetes, fish eggs, and even amphibian eggs and larvae. It is interesting to note that newts, as well as mudpuppies, breed underwater in the fall (mid-September through October). However, they do not lay their eggs until the following spring. Eggs are laid singly or in clusters attached to aquatic vegetation. These are primarily aquatic amphibians (despite their terrestrial phases), and are rarely seen for that reason.
Newts are active throughout the year. When larvae hatch, they either metamorphose into terrestrial juveniles (red efts) or become aquatic adults. The red eft stage can last several years. Eventually the juvenile red-efts will become aquatic adults, which are sexually mature. The terrestrial adult phase occurs if pond drying is imminent. Aquatic adults can transform to this terrestrial phase and live on land until their pond regains its' water.
Remarks:Christoffel et al. shows the Central Newt as existing throughout the state of Wisconsin. I have had individuals brought to me by trappers from nearby Trempeleau County (WI) who have accidentally caught them in their crayfish nets, however, I have not encountered them near LaCrosse. I believe this to be bad luck on my part and I'm sure they exist somewhere in the area.