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
Development brings many changes about in the Italian crested newt. One of these is the alteration from oxyconformer to oxyregulator. Obviously, this difference will change how the newt deals with changes in its respiratory conditions. Another developmental change is the loss of external gills from juvenile stage to adulthood. This affects "T. carnifex" as the difference between being able to outreach the DBL (juvenile) and the inability to do this (adult). This inability introduces a diathesis to hypoxia in stagnant water. This is because there is a lack of convection in the water, and the oxygen is being subtracted more quickly than it can diffuse (due to oxygen’s slow diffusion constant through water).