below the nares to contact the maxilla on the side of the snout, possesses the opposite state. It is much shorter in poposauroids (compared to other pseudosuchians), restricted to only a portion of the lower edge of the nares. This has the added effect of allowing the maxilla to form the rest of the hole's lower and rear edge, with the front edge of the maxilla becoming concave as well. Although these snout features are rare among pseudosuchians, they are much more common in certain avemetatarsalians (bird-line archosaurs) such as pterosaurs and saurischian dinosaurs. The rear branch of the maxilla tapers in most poposauroids, with the exception of Qianosuchus. This contrasts with loricatans, in which this branch is rectangular in shape. However, poposauroids also possess several features which are unusual compared to archosaurs in general. For example, in most archosaurs each side of the braincase possesses a pit from where the internal carotid arteries may exit the brain. In early poposauroids, these pits migrated to the underside of the braincase, thereby resembling the primitive condition seen in archosaur relatives such as Euparkeria and proterochampsians. Nevertheless, this reversion is undone in shuvosaurids (and possibly earlier, although no braincase material is known in Poposaurus or Lotosaurus). In addition, most poposauroids possessed elongated necks, and all of them had long and thin cervical ribs. This second neck trait contrasts with the condition in other pseudosuchians, phytosaurs, and pterosaurs, which have short and stout cervical ribs. The neural spines of the dorsal (back) vertebrae are thin and plate-like, even in members of Poposauroidea without sails. This differs compared to the vertebrae of most other early pseudosuchians (as well as Euparkeria and phytosaurs), which have neural spines that expand outwards to form a flat, rectangular surface when seen from above. Hip Pelvis Like other reptiles, the pelvis of poposauroids is formed by three plate-like bones: the ilium which lies above the acetabulum (hip socket), the pubis which is below and in front of the acetabulum, and the ischium which is below and behind the acetabulum. The ilium is a large, complex bone, with a forward-pointing (preacetabular) process, a rear-pointing (postacetabular) process, and a lower portion which forms the upper edge of the acetabulum. In most archosaurs, the lower portion of the ilium is wedge-shaped, forming the inner face of a "closed" acetabulum. However, in poposauroids the lower portion of the ilium is concave, creating a