Common Language Summary
A bizarre sauropod dinosaur from Africa. By modern standards, most dinosaurs are pretty unusual animals. Nigersaurus taqueti , however, is bizarre by even dinosaurian standards. The delicate bones of this sauropod were collected from 110 million-year-old rocks of the Ténéré Desert, Niger. Studying these fossils required high-tech approaches (such as CT scanning, 3D computer visualization, and rapid prototyping) and traditional techniques (such as sculpture). The end result was the first good view of the skull of a rebbachisaurid, a group of sauropod dinosaurs related to the better known Diplodocus and Apatosaurus . The skull of Nigersaurus was particularly bizarre. Its more than 500 teeth were all positioned at the very front of the skull, and formed a tight-fitting dental battery. Microscopic studies of the teeth show that they were worn down very quickly and then replaced by others in the battery. These high rates of tooth wear are surprising given that the skull seems too lightly built to have engaged in extensive chewing. The brain of Nigersaurus was very small relative to body size and was basically primitive in structure. The animal was largely driven by instinct. Its olfactory lobes of the brain were smaller than in other sauropods, suggesting the sense of smell was less important. The inner ear turned out to be very informative. The hearing organ (cochlea) of sauropods generally is rudimentary but is even smaller in Nigersaurus , suggesting that its discrimination of airborne sounds was poor. The inner ear also provides information on head posture, and most diplodocoids have a strongly down-turned head. Nigersaurus , however, took this trend to its extreme in that its head pointed straight down. Although at first a surprising finding, it helps makes sense of the unusual feeding apparatus, showing that Nigersaurus was a ground-feeding “lawn-mower” using its front-mounted dentition to crop low-growing plants.