Of what fell beast did this olive drab carcass come?
It looks like you have SandGreen parts from probably two different sets...

The dinosaur head (x158), 2 tail sections (40396 and 40379), 2 sloped pieces (3039), and black Technic brick (3700) are likely the remains of a Baby Ankylosaurus/Young Ankylosaurus:



The wedge plate (2419) and curved brick (6091) are likely parts from a Red Planet Cruiser (also in the Alien Discovery set):