Today I checked out the report on Bunostegos. The news article that directed me to it is “Knobby-Faced Beast May Be Earliest Known To Stand Tall On All Fours.” This is a fossil that is grouped with other “parareptiles.” The Huffington post article said they were “pre-reptiles,” but actually they are believed by evolutionists to have evolved separately from true reptiles. Most of their “earliest” fossils appear after those of the “first” true reptile fossils. One exceptionally early parareptile fossil is Erpetonyx arsenaultorum. That was found in Carboniferous deposits. The parareptiles included a group that once was thought to be the closest to the ancestors of turtles, but the most recently proposed turtle ancestor, Pappochelys, belongs to a different group. Of course, the next new fossil could change that view again.
Bunostegos, along with most parareptile fossils, was found in Permian strata, the ones dated just before Triassic, the first of the “Age of Dinosaurs.” One of the things that make dinosaurs different from other reptiles is that their legs were arranged straight down from their shoulder and hip sockets, whereas lizards and alligators have their legs splayed out to the sides. So were those of the parareptiles, although some had strangely long shoulder and hip bones and were thought to have had their legs held at an angle. Bunostegos was already known as a remarkable creature due to the big rounded lumps on its skull; now more study on its leg bones indicates that its four legs were mounted straight up-and-down, and according to its standard dating, long before there were any dinosaurs.
So what we have hear is something with a bizarre skull and on top of that, as the technical report says, “numerous postcranial autapomorphies” — many unique traits. Once again we see the pattern of a large group of presumed ancestors (amphibians), a few candidates for ancestors intermediate to another large group, and then all the members of the next large group, in this case the reptiles, including all the diversity in these parareptiles and the many different true reptiles also found in the Permian. Also, see what you get when you do a web search for “Permian amphibians.” The Permian is sometimes called “the Age of Amphibians.” One good (evolutionary) link I found is “300 Million Years of Amphibian Evolution.” I also like to use the Tree of Life web project site. Look at all the “sister groups” on its “Terrestrial Vertebrates” page, then follow the link to the page on Amniota, and note how Synapsida (mammals and their extinct relatives) did not evolve from reptiles (Anapsida, which includes our new friend Bunostegos in the Pareiasauria, a lot of other weird and wonderful but extinct forms, and Diapsida, which includes dinosaurs, lizards alligators and birds), but supposedly evolved directly from a common ancestor. Note also the alternate diagrams of supposed relationships when using different criteria or data sets. Verrrry interesting.