Small amphibian whose species include the Palmate, Great Crested and Smooth (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
newt
(Other definitions for newt that I've seen before include "Semiaquatic amphibian" , "Went (anag.)" , "Medical worker" , "Amphibious creature" , "Went to find amphibian" .)