Brazil to group with the nigersaurines, thereby expanding this lineage more widely (making palaeobiogeographic hypotheses for this group less reliable). Palaeobiology Though it had large nostrils and a fleshy snout, Sereno and colleagues found that Nigersaurus had an underdeveloped olfactory region of its brain and thus did not have an advanced sense of smell. Its brain-to-body-mass ratio was average for a reptile, and smaller than those of ornithischians and non-coelurosaurian theropods. The cerebrum comprised about 30% of the brain volume, as in many other dinosaurs. The American palaeoartist Mark Hallett and paleontologist Mathew J. Wedel and stated in 2016 that while sauropods in general could use their long necks to detect predators from afar, this would not apply to the short-necked Nigersaurus. They pointed out that the eyes of Nigersaurus were placed further towards the top of the skull than in most other sauropods, above the muzzle, which would give it overlapping fields of view. Its visual field would have been at or close to 360 degrees, and hypersensitivity of movement would have been important to a vulnerable prey-animal. In 2017, the Argentinian palaeontologist Lucio M. Ibiricu and colleagues examined the postcranial skeletal pneumaticity in the skeletons of rebbachisaurids, and suggested that it was an adaptation for lowering the density of the skeleton, and that this could have decreased the muscle energy needed to move the body, as well as the heat generated in the process. Since several rebbachisaurids inhabited latitudes that would have been tropical to subtropical in the Middle Cretaceous, this pneumaticity may have helped the animals cope with the very high temperatures. According to Ibiricu and colleagues, this adaptation may be a reason why rebbachisaurids were the only group of diplodocoids that survived into the Late Cretaceous. Diet and feeding Nigersaurus was suggested by Sereno and colleagues to be a ground-level, non-selective browser. The width of the muzzle and lateral orientation of the tooth row show that the sauropod could gather much food and crop it close to the ground, within of the surface. This is further supported by facets on the labial (externally facing) side of the upper teeth, similar to Dicraeosaurus and Diplodocus, which are evidence that food or substrate wore the animal's teeth as it fed. Nigersaurus also bears signs of low-angle tooth-to-tooth wear on the inside of the maxillary crowns, which suggests that jaw movement was limited to precise up-and-down motions. Worn teeth