Well this just proves that even 100 million years ago, falling for a straight girl will always lead to pain.
I dunno. Tyra-chan might just be confused. She's young, new to these kinds of feelings, clearly hasn't learned to tell the difference between her "desire to devour" and her, um, "desire to devour" . . . and she's certainly not afraid to transgress against societal norms for the sake of love. I mean, a herbivore!
I say Spino-chan has a chance and it could work out just fine.