Spotted paddle-tail newt
"Pachytriton" species are stout-bodied, smooth-skinned aquatic newts. Their heads are large and flattened, and they have conspicuous labial folds and short, stubby legs and toes. They breathe through both lungs and skin. 
"P. brevipes" ranges from 5.5 to 7.5 in as an adult. It has prominent labial folds, long digits, and smooth skin, which differs from the tuberculate skin typical of newts.
Italian crested newt
Prolactin is one of the major hormones released with the changing temperatures, and as such, plays an important role in the transport of sodium and water ions. An increase of this hormone results in the decreased permeability of the skin as well as a reduction of active sodium uptake, which seems to play a less important role than previously thought. This becomes apparent when newts are in their aquatic environment. During winter months, prolactin is released into the circulatory system, which drives "T. carnifex" into the aquatic environment (Lodi 1981). Not only does this hormone prompt a change of habitat for the newt, it reduces the active transport of sodium ions. This happens because there is more water readily available to the newt for uptake as compared to its terrestrial dwelling during the summer months.