[BipolarBob]

I saw a documentary that showed them below a thermocline in the ocean.

https://www.imdb.com/title/tt4779682/

[Red Badger]

It would not surprise me that one or more were still alive.

I found a meg tooth once about 45 years ago at Camp LeJeune, NC, the size of the palm of your hand. Forget whatever happened to it over the years.

But it didn’t look millions of years old.......................

[Blueflag]

Most everything below the photic zone is below one or more thermoclines. 😉