downturned (or hooked), whereas that of the front portion of the maxillae was upturned. This morphology resulted in a sigmoid or S shaped margin of the lower upper tooth row, in which the teeth from the front of the maxilla were projecting forward. The snout was particularly narrow directly behind the rosette; this area received the large teeth of the mandible. The maxilla and premaxilla of Baryonyx fit together in a complex articulation, and the resulting gap between the upper and lower jaw is known as the . A downturned premaxilla and a sigmoid lower margin of the upper tooth row was also present in distantly related theropods such as Dilophosaurus. The snout had extensive (openings), which would have been exits for blood vessels and nerves, and the maxilla appears to have housed sinuses. Baryonyx had a rudimentary , similar to crocodiles but unlike most theropod dinosaurs. A rugose (roughly wrinkled) surface suggests the presence of a horny pad in the roof of the mouth. The nasal bones were fused, which distinguished Baryonyx from other spinosaurids, and a sagittal crest was present above the eyes, on the upper mid-line of the nasals. This crest was triangular, narrow, and sharp in its front part, and was distinct from those of other spinosaurids in ending hind wards in a cross-shaped process. The lacrimal bone in front of the eye appears to have formed a horn core similar to those seen, for example, in Allosaurus, and was distinct from other spinosaurids in being solid and almost triangular. The occiput was narrow, with the paroccipital processes pointing outwards horizontally, and the were lengthened, descending far below the (the lowermost bone of the occiput). Sereno and colleagues suggested that some of Baryonyx cranial bones had been misidentified by Charig and Milner, resulting in the occiput being reconstructed as too deep, and that the skull was instead probably as low, long and narrow as that of Suchomimus. The front of the dentary in the mandible sloped upwards towards the curve of the snout. The dentary was very long and shallow, with a prominent Meckelian groove on the inner side. The , where the two halves of the lower jaw connected at the front, was particularly short. The rest of the lower jaw was fragile; the hind third was much thinner than the front, with a blade-like appearance. The front part of the dentary curved outwards to