Well, that just beats all. We community college instructors often revel in the fact that we know a little bit about a lot of things instead of a lot about some specific things, but sometimes it helps to actually know a lot. Back when we found the mystery sample of the Chinle Formation, we wondered if it was a coral, and how a coral could have gotten into the Chinle, which is a terrestrial formation.
As I described in the previous post, I thought I had discovered the answer to the mystery when I saw a metoposaurus in the visitor center at Petrified Forest National Park (shown in the photo above), given the unique pits in the skull plates. The metoposaurs were large carniverous amphibians. I couldn't exactly make my sample line up with any particular part of the skull, but it was an adequate answer for me, the non-expert. In the best tradition of bad science, I didn't continue to explore other hypotheses once I had an answer that satisfied me. That's the kind of attitude that drives me nuts when my students are trying to identify rock and mineral specimens ("it's clear so it must be quartz, even if it cleaves").
Of course, running a blog demonstrates your ignorance to anyone who wants to pay attention, so I say thank you to an actual paleontologist, Jerry Harris, who suggested my sample could also be a phytosaur scute. So I am properly chastised for not covering my bases (y'all notice I could have said I knew it was a phytosaur all along....). I am at the same time happy to find that I might have a piece of phytosaur. They were one of the fierce predators of the Triassic: somewhat crocodile shaped, up to 30 feet long, and overall pretty cool.
Picture from Wikipedia
(This post has been revised)