Identification: Adult Eastern Newts display a countershaded camouflage with an olive-green, dark-green, or yellowish-brown dorsum (back) and a yellowish ventral (belly) coloration (Beane et al. 2010). Their skin is peppered with small black specks, and many individuals possess larger red markings in the form of spots or broken stripes with black margins. The largest of these red spots usually form a distinct row on each side of the torso (Jensen et al. 2008; Niemiller and Reynolds 2011). The presence and abundance of these red markings vary greatly among subspecies. A conspicuous tail fin, which is laterally compressed, is present in aquatic larvae and adults, and this tail fin accounts for 50% of their total length (Gibbs et al. 2007; Niemiller and Reynolds 2011).
Aquatic larvae are 7-9 mm in total length when hatched, have a yellowish-green coloration, and prominent external gills. Larvae also typically have a distinct stripe that extends from their snout, through each eye, and to the gills (Jensen et al. 2008; Niemiller and Reynolds 2011). Terrestrial juveniles, referred to as efts, have coarse skin and an aposematic (warning) coloration that ranges from reddish-brown to bright red-orange (Petranka 1998; Beane et al. 2010; Niemiller and Reynolds 2011). Efts typically measure 35-85 mm in total length and lack the distinct tail fin present in adults (Niemiller and Reynolds 2011). Red skin spots, like those of adults, are also commonly present in the eft stage of some subspecies (Petranka 1998; Niemiller and Reynolds 2011).
Four subspecies of the Eastern Newt (Notophthalmus viridescens) are recognized in the United States: Red Spotted Newt (Notophthalmus viridescens viridescens), Central Newt (Notophthalmus viridescens louisianensis), Broken Striped Newt (Notophthalmus viridescens dorsalis), and Peninsular Newt (Notophthalmus viridescens piaropicola) (Petranka 1998; Jensen et al. 2008; Niemiller and Reynolds 2011; Powell et al. 2016).
| || Red Spotted Newt || Central Newt || Broken Striped Newt || Peninsular Newt |
| Distinct Coloration || Distinct red spots encircled by prominent black margins in all life stages (Petranka 1998; Powell et al. 2016). The number of red spots usually averages from 2 to 7 per individual (Gibbs et al. 2007). || Often lacks red dorsal spots. If these spots are present, they are reduced and not fully outlined by black margins (Petranka 1998; Powell et al. 2016; Niemiller and Reynolds 2011) || Lacks red spots, but has prominent red stripes bordered in black margins extending from the head to the hind legs. Stripes typically broken at least once or twice and rarely extend onto the tail (Petranka 1998; Powell et al. 2016). || Dark olive-green, brown, or almost black coloration. Lacks the red spots, and venter heavy marked with black spots. (Petranka 1998, Powell et al. 2016). |
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Notophthalmus viridescens are found here.
Table last updated 11/30/2018
† Populations may not be currently present.
Ecology: Eastern Newts have a complex life cycle with four distinct life stages: eggs, larvae, efts, and aquatic adults (Petranka 1998; Gibbs et al. 2007; Jensen et al. 2008; Niemiller and Reynolds 2011). Breeding occurs primarily during the autumn and spring months in ponds, lakes, swamps, and ephemeral pools with dense vegetation and low flow (Petranka 1998; Trauth et al. 2004; Niemiller and Reynolds 2011). While males likely breed annually, females may skip years between reproductive events (Niemiller and Reynolds 2011). In late spring, each female lays around 200-350 eggs on submerged vegetation in the littoral zone (Gibbs et al. 2007; Niemiller and Reynolds 2011). The eggs hatch within 3-5 weeks after being laid, and the larvae are typically 7-9 mm at the time of hatching (Gibbs et al. 2007; Jensen et al. 2008; Niemiller and Reynolds 2011).
Larvae are fully aquatic, have bushy external gills, and have well developed tail fins (Petranka 1998). At this stage they mainly consume small invertebrates such as microcrustaceans, and insect larvae (Gibbs et al. 2007). After 2-5 months, larvae metamorphose into their brightly colored juvenile (eft) stage, and they become exclusively terrestrial. During this metamorphose, larvae lose their gills and develop a thick orange skin with poison glands containing a potent neurotoxin called tetrodotoxin (Gibbs et al. 2007; Niemiller and Reynolds 2011). Their thick skin helps prevent desiccation, and the neurotoxin renders them unpalatable to many predators (Petranka 1998; Gibbs et al. 2007; Niemiller and Reynolds 2011). Efts will inhabit damp forested habitats for up to 2 to 7 years before morphing into their fully aquatic adult form. During this time, efts generally remain hidden under moist leaf litter and debris, but they can occasionally be seen moving around during rainy days and nights (Niemiller and Reynolds 2011).
After their terrestrial stage, efts migrate back to the water to metamorphose into adults. Most will then remain aquatic for the rest of their lives (Gibbs et al. 2007). During this final metamorphose, adults regain their olive-yellow countershading and their prominent tail fin (Petranka 1998; Beane et al. 2010). Adult Eastern Newts feed on a variety of invertebrates and small vertebrates. Their diet consists mainly of arthropods, worms, leeches, and both the eggs and larvae of amphibians (Gibbs et al. 2007, Niemiller and Reynolds 2011). In total, Eastern Newts can live up to 15 years or more (Niemiller and Reynolds 2011).
References: (click for full references)
Beane, J. C., A. L. Braswell, J. C. Mitchell, W. M. Palmer, and J. R. Harrison III. 2010. Amphibians and Reptiles of the Carolinas and Virginia. 2nd edition. University of North Carolina Press, Chapel Hill, NC.
Gibbs, J. P., A. R. Breisch, P. K. Ducey, G. Johnson, the late J. Behler, and R. Bothner. 2007. The Amphibians and Reptiles of New York State (Identification, Natural History, and Conservation). Oxford University Press, New York, NY.
Jensen, J. B., C. D. Camp, W. Gibbons, and M. J. Elliott. 2008. Amphibians and Reptiles of Georgia. 1st edition. The University of Georgia Press, Athens, GA.
Niemiller, M.L., and R.G. Reynolds (Editors). 2011. The amphibians of Tennessee. The University of Tennessee Press, Knoxville, TN.
Petranka, J.W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press.
Powell, R., R. Conant, and J.T. Collins. 2016. Peterson field guide to reptiles and amphibians of eastern and central North America. 4 edition. Houghton Mifflin Harcourt Publishing Company, New York, NY.
Smith, K.G. 2006. Keystone Predators (Eastern Newts, Notophthalmus viridescens) Reduce the Impacts of an Aquatic Native species. Oecologia 148(2):342-349.
Trauth, S.E., H.W. Robinson, and M.V. Plummer. 2004. The amphibians and reptiles of Arkansas. The University of Arkansas Press, Fayetteville, AR.
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.