Nigersaurus taqueti

Nigersaurus taqueti was a highly specialized rebbachisaurid sauropod from the Early Cretaceous Elrhaz Formation of Niger. Its skull was lighter and more open than that of almost any other dinosaur, yet the front of its squared muzzle housed tightly packed dental batteries containing hundreds of replacement teeth. All active teeth were concentrated across the front edge of the jaws. CT scans helped researchers reconstruct the fragile skull and inner ear, showing an animal adapted for repeatedly cropping vegetation close to ground level. At about nine metres long, Nigersaurus was modest in size for a sauropod.

Its fossils occur between approximately 115 and 105 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The broad muzzle was wider than the back of the skull and carried all tooth positions along its front margin. Each narrow working tooth was backed by a column of replacements; across the jaws the animal held more than five hundred active and replacement teeth. Individual teeth were replaced roughly monthly. Large openings and paper-thin struts made the skull exceptionally light. The neck contained only thirteen vertebrae and remained short for a sauropod. Air-filled spaces occupied much of the presacral vertebrae, and the limbs were relatively slender.

• Broad squared muzzle wider than the rear of the skull
• All tooth positions concentrated along the front of the jaws
• More than five hundred active and replacement teeth
• Extremely lightweight skull built from thin bony struts
• Short neck containing thirteen cervical vertebrae
• Highly air-filled presacral vertebrae

Philippe Taquet's expeditions recovered the first recognizable material from Gadoufaoua in the 1960s and 1970s, but the fragile bones were initially difficult to interpret. Paul Sereno and ten colleagues named Nigersaurus taqueti in 1999 from material including holotype MNN GAD512. Expeditions in 1997 and 2000 recovered more skull and skeletal remains. In 2007, Sereno and colleagues published a detailed digital reconstruction based on CT scanning. The genus honours the Republic of Niger and the species honours Taquet.

Naming authors: Paul C. Sereno, Allison L. Beck, Didier B. Dutheil and 8 coauthors.

The Elrhaz Formation at Gadoufaoua represents river channels and vegetated floodplains in what is now the Ténéré Desert. Nigersaurus lived alongside the sauropod Jobaria, the herbivores Ouranosaurus and Lurdusaurus, the spinosaurid Suchomimus, crocodyliforms, turtles and fish. The modern desert landscape should not be mistaken for its Cretaceous environment.

Nigersaurus was a quadrupedal herbivore specialized for cropping low vegetation. Its broad muzzle could gather many small plants at once, while rapid tooth replacement compensated for heavy wear. Inner-ear orientation and muzzle anatomy support habitual low browsing, but they do not prove that the neck was permanently held downward. No direct evidence establishes herding, daily feeding schedule or preferred plant species.

• Its jaws contained more than five hundred active and replacement teeth at a time.
• New teeth replaced worn teeth approximately every month.
• The skull was so delicate that CT scanning was essential to reconstruct its anatomy.
• Although a sauropod, its neck was comparatively short and contained thirteen vertebrae.

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1. 01
   Cretaceous sauropods from the Sahara and the uneven rate of skeletal evolution among dinosaurs

   Paul C. Sereno, Allison L. Beck, Didier B. Dutheil and 8 coauthors · Science 286(5443), 1342–1347 · 1999

   Open source
2. 02
   Structural extremes in a Cretaceous dinosaur

   Paul C. Sereno, Jeffrey A. Wilson, Lawrence M. Witmer and 4 coauthors · PLOS ONE 2(11), e1230 · 2007

   Open source
3. 03
   Nigersaurus taqueti CT dataset

   Digital Morphology, University of Texas at Austin

   Open source