Filtering by green Pokemon eliminates 712 Pokemon, then eliminating Pokemon without claws eliminates 80 Pokemon, leaving: Rayquaza, Tyranitar, Chesnaught, Quilladin, Flygon, Axew, Fraxure, Kecleon, Sceptile, and Electrike. Now, looking at the sprite history, the green appeared in Gen 4, meaning that Fraxure, Axew, Quilladin, Chesnaught aren't the Pokemon. The Pokemon has no wings, meaning it can be Sceptile, Kecleon or Tyranitar. The tail is flat, meaning Sceptile, Tyranitar, and Kecleon are out. But one Pokemon fits everything: Rhydon. It has a very small green tint, has claws, has horn, has flat tail, and was in Gen 4.
Edit: Rhydon's shiny is much more green that original Rhydon
