Sense Sonnet - Pumper

Ichthyosaur

"Fish lizard" - the ichthyosaur
Lived in the water long ago,
Two hundred million years or more.
It was the dolphin we now know.
Came from lunged reptiles on the land,
And over time became like fish.
But had ten fingers on each hand,
Keeping the trait to be grabbish.
And they did have the largest eyes
Of all vertebrates then around,
Could be long as a house in size.
Lots of fossils of them are found.

Researchers check the remains out.
What was this fish lizard about?