Hypocercal Tails
Looks like three groups of marine diapsids, ichthyosaurs, mosasaurs, and thalattosuchians, all evolved “hypocercal” tail fins.
paleontology
Tate Geological Museum
A Museum You Should Visit
If you happen to be in Casper, Wyoming, you should visit Tate Geological Museum. It’s a small, but very well done geology and paleontology museum. There’s interesting things for most family members, even well-informed 4-year-olds could have fun and learn things.