Could a medium sized animal live in an extinct deep sea vent

For science class we had to make up an undiscovered organism for the biome we chose. My group had the Benthic Zone. The teacher said we could make up whatever we wanted for our organism so we made a dinosaur with wings that shoots water out of it's butt to go faster. Yeah... well, we had to make up a place for it to live so we said it could live in the deep sea vents that are extinct to hide it's young while the adults go hunt for food. I don't know if this is possible because deep sea vents are pretty small and only small life lives in them. So yeah would it be plausible? This is a really dumb question. And would it be normal for an animal down there to feed it's young because it's more likely for the animals down there to eat there young.

Dinosaurs are reptiles. There was no aquatic dinosaur that we know of, but there were a wide variety of aquatic reptiles, including the living sea turtles. Many extinct aquatic reptiles (such as pliosaurs, mosasaurs and plesiosaurs) lived in the sea, but they need to breathe air. Therefore they cannot hide in the deep sea bottom, since they eventually need to come up for air. A deep sea vent may keep them warm, but these vents are not permanent. They may appear and then they may vanish after a while. To live in these, one must be able to move from one vent to another and must also have a way to anticipate where the next one may turn up, because it would be difficult to just wander around hoping to find the next one. Another difficulty for marine reptiles is egg laying. Some, like the ichthyosaurs, have live birth. No dinosaur has been shown to have evolved live birth. Therefore it is another strike against dinosaurs becoming not only marine, but living near the bottom.

For these reasons, it is implausible that one can find a deep sea living dinosaur either during the Mesozoic or now.