First of all, hello to all of you on the Fossil forum- My name is Erik. newbie here, first post.
Secondly, I'm exceptionally curious as to what organism in the fossil record has the first confirmed gastrolith (non-exolith) presence. I found and read through Fruitbat's research, and he had some very interesting articles about gastroliths, some of which I've seen, some of which I have not. I feel that Gastroliths are incredibly important to Archosaur evolution because they fulfill much the same role that differentiated teeth for thorough mastication do in mammals. Of course, proving that a differentiated tooth came from a synapsid is much, much easier than proving a gastrolith found outside of any skeletal remains (an exolith) came from an Archosaur.
I'm sure many of you know most of this already... any information you can provide would be appreciated.