- Tyranitar has spikes; T. rex does not
- Tyranitar has good posture; T. rex does not
- Tyranitar has proportionate arms; T. rex does not
- T. rex has a long jaw; Tyranitar does not
- T. rex has long legs that lift its body a good distance off the ground; Tyranitar does not
- T. rex has many, many teeth; Tyranitar does not
CONCLUSION: Besides the fact that they're big bipedal reptiles, T. rex and Tyranitar don't really resemble one another. So we still don't have a T. rex Pokemon.