Systematics
About two thirds of all species of the family Salamandridae, comprising the following genera, are commonly called "newts":
- Calotriton Spanish brook newts
- Cynops firebelly newts
- Echinotriton spiny newts
- Ichthyosaura Alpine newts
- Lissotriton small bodied newts
- Neurergus spotted newts
- Notophthalmus Eastern newts
- Ommatotriton banded newts
- Pachytriton paddle-tail newts
- Paramesotriton warty newts
- Pleurodeles ribbed newts
- Taricha Pacific newts
- Triturus crested newts
- Tylototriton crocodile newts
The term "newt" has traditionally been seen as an exclusively functional term for salamanders living in water, and not a systematic unit. The relationship between the genera has been uncertain, although it has been suggested that they constitute a natural systematic unit and newer molecular analyses tend to support this position. Newts only appear in one subfamily of salamanders, the Pleurodelinae (of the family Salamandridae), however, Salamandrina and Euproctus, which are sometimes listed as Pleurodelinae, are not newts. Whether these are basal to the subfamily (and thus the sister group of the newt group) or derived, making the newts an evolutionary grade (an "incomplete" systematic unit, where not all branches of the family tree belong to the group) is currently not known.
Read more about this topic: Newt