In a paper in the Journal of Zoological Systematics and Evolutionary Research we explore the evolution of body form in crested newts. In general crested newts started out with large bodies with a short trunk and a wide head. Over time smaller bodies with a longer trunk and narrower had were added to the crested newt repertoire. Ecology likely played an important role in the radiation of body shapes in crested newts.

Reference: Vukov, T.D., Sotiropoulos, K., Wielstra, B., Džukić, G., Kalezić, M.L. (2011). The evolution of the adult body form of the crested newt (Triturus cristatus superspecies, Caudata, Salamandridae). Journal of Zoological Systematics and Evolutionary Research 49(4): 324-334.