Notophthalmus viridescens (Eastern Newt)

Notophthalmus viridescens (Eastern Newt)

Field Experience & Observation: On our very first field trip to the Caw Caw Interpretive Center in Ravenel, SC we found several Notophthalmus viridescens or the Eastern Newt. Newts are their own salamander family and are distinguished from other salamanders for their indistinct costal grooves and non-slimy rougher skin. These Eastern Newts had been caught in the minnow traps that were placed in a very wet and muddy area. These newts were a deep rep with the tell-tale large red outlined black spots on their backs (we did not count to find all 21 spots) and speckles of dark spots on their bellies. This red coloring is what distinguished them from being adults since adults are yellowish to dark greenish brown. All were in the eft stage, even though the minnow traps were found in the water. These efts were pretty hefty at about 3 inches long, but despite our efforts it was too hard to figure out their sexes (males have high tail fins, black tubercles on their thighs/rear feet, and a swollen cloaca when breeding). With both the friendly newts and no-see-ums, Caw Caw was a beautiful place to visit. I really liked getting to find these newts because I have never seen them before in their native habitat. 

Life History Stages & Behavior: I think that newts have the coolest life history of all the amphibians that we have studied this year in lab. Overall newts are aquatic critters, except for their terrestrial “eft” or juvenile stage. Aquatic eggs will become aquatic larvae that then transform into terrestrial efts. Some species however will skip this eft stage and exhibit neotony. Efts do not like direct sunlight, but they are not afraid to venture around during the day light. I think that the efts are not afraid because their bright coloring warns predators that they will secrete toxins from their skin glands. When efts are changing into from larvae they can be a yellowish color and when changing into adults their coloring can become very dark to almost a black color. The most amazing aspect of these morphological changes are the presence of gills, loss of gills for terrestrially, and the regaining of gills for adulthood.

Habitat & Range: Newts like ponds, small lakes, marshes, swamps, ditches, quiet areas of streams, and other places with continuous unpolluted water. Most of these bodies of water will have few fish (i.e. fewer predators) and lots of aquatic vegetation to hide in. Adults are seen to swim, crawl along the bottom, and just rest in a motionless state. Terrestrial efts will live in the moist woodland areas that around their adult counterparts.

Within the U.S. there are four regional varieties of the Eastern Newt – N. viridescens viridescens (Red Spotted), N. viridescens dorsalis (Broken-Striped), N. viridescens lousianesis (Central), N. viridescens piaropicola (Peninsula). All of these regional varieties exhibit a difference in coloring and patterns along with some other life habits like neotony.

So which one did we find at Caw Caw? Based on the range map it should have been the Central Newt that is normally found without red spots (or their spots will be partly outlined in black) in swamplands, woodland swamps, ditches and river bottoms. The Central Newt often skips the eft stage because of harsher (hotter, drier) environmental conditions. However, the Red Spotted and Central varieties are very similar and they can intergrade. I think that the ones that we found at Caw Caw are Central variety because this is a great habitat they were exhibiting the eft stage.

Sources:

Reptiles & Amphibians Eastern/Central Guidebook
http://www.caudata.org/cc/species/Notophthalmus/N_viridescens.shtml