Yes, PLATYPUS is a Scrabble word!

Letter values in Scrabble US: P 3, L 1, A 1, T 1, Y 4, P 3, U 1, S 1.

Is it a valid word?

PLATYPUS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

small densely furred aquatic monotreme of Australia and Tasmania having a broad bill and tail and webbed feet; only species in the family Ornithorhynchidae

Also: duckbilled platypus, duck-billed platypus, ornithorhynchus anatinus.