Xilousuchus sapingensis has been reclassified as an archosaur. The specimen – a skull and 10 vertebrae – was found in the Heshanggou Formation in northern China.
The fossil was originally classified as an archosauriform, a "cousin" of archosaurs, rather than a true archosaur, but that was before the discovery of more complete early archosaur specimens from other parts of the Triassic period. The researchers examined bones from the specimen in detail, comparing them to those from the closest relatives of archosaurs, and discovered that X. sapingensis differed from virtually every archosauriform.
Arizonasaurus, a very close relative of Xilousuchus found in Arizona.
The new research places X. sapingensis firmly within the archosaur family tree, providing evidence that the early members of the crocodile and bird family trees evolved earlier than previously thought. link
This article is from a special issue of Earth and Environmental Science Transactions of the Royal Society of Edinburgh on Late Triassic Terrestrial Biotas and the Rise of Dinosaurs.