I really like this artwork, hooray for dinosaur...type...things. lawl. I don't know anything about these creatures, but I do know that you've made them look cool
I like the colours you used in the picture above, the calming blue goes so well with the pinks. Also, the under-sea and watery effects are gorgeous.
However, I think I like the second picture better. I like it's composition; the way the top half is above water and the second half is below, that effect works really nicely. I like the green colours, and the rays of sunshine streaming in through the trees; lovely!
My only criticism would be that both the sea and swamp look a tad crowded with all those animals. But I suppose that was part of the assignment?
btw, did you really paint this digitally? Truly stunning painting skills you've got...anyway, excellent work!