I just read a short note, Earliest Triassic ichthyosaur fossils push back oceanic reptile origins, from Current Biology 33:159-179, March 2023, Benjamin Kear, Victoria Engelschion, Oyvind Hammer, Aubrey Roberts, Jorn Hurum.
You should make the trip to Thermopolis, WY to visit the Wyoming Dinosaur Center This museum has the most mounted skeletons of Mesozoic vertebrates I’ve seen in a single institution, plus many more interesting fossils or casts.
Wyoming Dinosaur Center has some great Paleozoic material. There’s a placoderm and ostracoderm exhibit, covering important taxa that you don’t see exhibited often. The Center has two Dunkleosteus armored skulls, both different than the cast on display at the Denver Museum of Nature and Science.
Thalattosuchians are an under-rated clade of mesozoic animals. Part of Pseudosuchia, the crocodile-like archosaurs, they were completely adapted to a marine lifestyle.
That’s the shoulder and pelvic girdle of the plesiosaur (elasmosaur maybe) skeleton cast that the Fort Collins Museum of Discovery has on display.
Looks like three groups of marine diapsids, ichthyosaurs, mosasaurs, and thalattosuchians, all evolved “hypocercal” tail fins.
