Yarasuchus

Yarasuchus (meaning "red crocodile") is an extinct genus of avemetatarsalian archosaur that lived during the Anisian stage of the Middle Triassic of India. The genus was named and described in 2005 from a collection of disarticulated but fairly complete fossil material found from the Middle Triassic Yerrapalli Formation. The material is thought to be from two individuals, possibly three, with one being much more complete and articulated than the other. The type and only species is Y. deccanensis. Yarasuchus was a quadruped roughly 2–2.5 metres (6.6–8.2 ft) long, with an elongated neck and tall spines on its vertebrae. Unlike other quadrupedal Triassic reptiles, the limbs and shoulders of Yarasuchus were slender, and more like those of ornithodirans.

Yarasuchus has had a complicated taxonomic history, after originally being described as a "prestosuchid rauisuchian", it was later variously recovered as a poposauroid pseudosuchian and a non-archosaurian archosauriform of unstable position. In 2017 it was determined to be related to the similarly enigmatic Triassic reptiles Teleocrater, Dongusuchus and Spondylosoma. Together, they belong to a group called Aphanosauria and are placed at the base of Avemetatarsalia, sister to Ornithodira, making Yarasuchus one of the earliest diverging bird-line archosaurs known. The relative completeness of Yarasuchus and its evolutionary position helps to shed light on the origins of later, well known bird-line archosaurs such as the dinosaurs and pterosaurs.