Nigersaurus
As Nigersaurus you would spend your life face-down in the undergrowth, mowing ferns with a mouth as wide as your head and hundreds of teeth on standby.
Ground-level grazer of the Sahara
Around 115–105 million years ago, the area that is now the Ténéré Desert in Niger was a lush floodplain with rivers and lakes. Nigersaurus taqueti, found in the Elrhaz Formation and fully described by Paul Sereno and colleagues in 1999 and 2007, lived there alongside the fish-eating spinosaurid Suchomimus, the sail-backed Ouranosaurus and the giant crocodile relative Sarcosuchus.
It was a rebbachisaurid sauropod, only about 9 metres long, with a short neck by sauropod standards.
A mouth like a vacuum cleaner
The jaws were squared off at the front, wider than any other part of the skull, with teeth packed in a straight line across the muzzle. Behind each working tooth sat a column of replacements, giving more than 500 teeth in the mouth at once. A 2013 study of tooth growth lines estimated each tooth was replaced roughly every 14 days – among the fastest rates known for any dinosaur.
That set-up suits cropping soft, low plants such as ferns and horsetails. The skull itself was astonishingly light, with some bones thin enough to let light through, and Sereno nicknamed it a “Mesozoic cow”.
Head down by default
Based on the orientation of the inner ear canals, Sereno’s team argued that Nigersaurus habitually held its snout pointing down towards the ground. That interpretation is debated – inner ear orientation is not a perfect guide to posture – but the wear on its teeth confirms you would have fed almost entirely at ground level.
The French palaeontologist Philippe Taquet, honoured in the species name, first reported its bones in the 1970s, but only fragments were known until Sereno’s expeditions of the 1990s recovered enough material to reconstruct the skull.
