nerve foramina. The prootic forms much of the front edge of the paroccipital process, akin to the condition in archosauriforms. Another archosauriform-like feature is the presence of a laterosphenoid, an additional braincase component in front of the prootic and above the exit hole for the trigeminal nerve (also known as cranial nerve V). The laterosphenoid is small, similar to the condition in Azendohsaurus. The upper rear part of the braincase is formed by the supraoccipitals, which were presumably fused together as a continuous surface sloping smoothly down to the foramen magnum. In the lower jaw, the dentaries meet each other at a robust symphysis with an interdigitating suture. The front end of the dentary hosts a prominent keel on its lower edge, a unique trait of the species. There were at least 18 dentary teeth; the first three are by far the largest teeth in the skull, forming the lower half of the interlocking “fish trap” with the premaxilla. Most other teeth in the dentary are small, with the exception of the tenth tooth, which juts up to pierce the maxilla. The remainder of the jaw contains the same set of bones as in T. longobardicus, but some details differ in T. hydroides. For example, the splenial is plate-like and covers a larger portion of the internal dentary than in T. longobardicus. In addition, the rear of the dentary overlaps a large portion of the surangular, rather than the surangular acting as the overlapping bone where they meet. The surangular internally bears a large fossa for the jaw's adductor (vertical biting) muscles, and a prominent surangular foramen is positioned in front of the jaw joint. Neck The most recognisable feature of Tanystropheus is its hyperelongate neck, equivalent to the combined length of the body and tail. Tanystropheus had 13 massive cervical (neck) vertebrae, though the first two were smaller and less strongly developed. The atlas (first cervical), which connects to the skull, is a small, four-part bone complex. It consists of an atlantal intercentrum (small lower component) and pleurocentrum (large lower component), and a pair of atlantal neural arches (prong-like upper components). There does not appear to be a proatlas, which slots between the atlas and skull in some other reptiles. The intercentrum and pleurocentrum are not fused to each other, unlike the fused atlas of allokotosaurs. The tiny crescent-shaped intercentrum is overlain by a semicircular pleurocentrum, which acts as