Salamandrids occur in Europe and Asia, with a small representation in eastern and central North America. Their known fossil history extends into the Eocene. The family contains seven genera represented by more than 50 living species. Courtship and life histories are variable and complex. In North America most Notophthalmus have three stages during ontogeny, an aquatic larval form, a sexually immature terrestrial form, and a sexually mature aquatic stage. Other genera have just the aquatic larvae and terrestrial adult, but some Salamandra and Mertensiella skip the aquatic larvae and are live bearing. Many of these animals have very toxic skin secretions.

Mizuki and Parris (2006, Ecological Society of America, Abstract) found that the Eastern Newt, Notophthalmus viridescens, has a life cycle that shows polyphenism, where the larvae can metamorphose to terrestrial juveniles, aquatic lunged adults, or become paedomorphic adults depending on aquatic conditions. The four subspecies currently recognized are based upon the differences in morphology and polyphenism traits expressed in the different population. This suggests possible adaptive divergence in polyphenism within this species Previous work has demonstrated that the divergence in polyphenic expression among subspecies is likely shaped by different pond hydroperiod regimes, suggesting a potential role of life cycle polyphenism in the ecological divergence. They collected DNA samples throughout the species' range and analyzed mitochondrial cytochrome b sequences. Preliminary results support monophyly of N. v. viridescens and N. v. dorsalis, but do not support for monophyly for the other two subspecies, suggesting that ecological and geographical isolation, and possibly polyphenism may have contributed to diveregence in Notophthalmus.

Broken Striped Newt, Notophthalmus viridescens dorsalis (Harlan, 1829). Captive specimen from North Carolina. Inhabits the Coastal Plain of North and South Carolina. Habitats used include forest and forest edge ponds, swamps, and marshes. Adults are aquatic.

Eft stage of the Central Newt, Notophthalmus viridescens louisianensis (Wolterstorff, 1914). Captive specimens from western Tennessee. Eft stages are terrestrial and adults return to the water.