Paul Sereno’s Expeditions

• African Dinosaur Expeditions

  Niger, 1990. University of Chicago paleontologist Paul Sereno joins a British expedition that discovers abundant remains of the fossil fish coelacanth in the dinosaur-era rocks of Niger. Striking out on his own for 10 days with one assistant and one vehicle, Sereno encounters a local Tuareg nomad, who leads him to Fako, an impressive but remote dinosaur graveyard. With three days left in which to work, Sereno only has time to excavate the large leg bone of a juvenile sauropod, the long-necked dinosaur that turns out to be Jobaria. The bone now is on display at the University of Chicago’s John Crerar Library.

  Niger, 1993. Sereno returns to the 130-million-year-old dinosaur graveyard at Fako. Getting to Fako with a major expedition requires overcoming immense logistical challenges. Sereno’s team flies from Chicago to London, where they load their trucks with equipment that had been shipped in massive metal containers. The team ferries across the English Channel, drives across France, plies by ship across the Mediterranean Sea and lands in Algeria. From Algeria the team drives more than 1,000 miles across the Sahara Desert and finally into Niger. In addition to excavating giant sauropod skeletons, they discover the remains of a predator 30 feet long, Afrovenator abakensis (the hunter from Abaka, Africa). Afrovenator’s hunting equipment includes sickle-clawed, three-fingered hands and blade-like teeth two inches long.

  Morocco, 1995. Working in sediments 90 million years old, the expedition yields the skull of the largest predator ever to walk the Earth: Carcharodontosaurus saharicus (the shark-toothed reptile from the Sahara). Carcharodontosaurus grew to a length of 45 feet–five feet longer than Tyrannosaurus rex–yet its brain is only half the size of T. rex’s. Ernst Stromer von Reichenbach collected the first fragmentary bones and serrated teeth of the animal in Egypt at the start of the century. On April 24, 1944, a Royal Air Force bombing run destroyed the fossils, where they had been housed in Munich. Sereno matches the teeth with von Reichenbach’s descriptions, bringing the animal back to scientific life. Expedition team member Gabrielle Lyon also finds a new species, Deltadromeus agilis (agile delta runner). A fleet-footed predator, Deltadromeus grew to the size of a Tyrannosaur.

  Niger, 1997. Sereno’s team recovers two new dinosaur species, each from a different time: Suchomimus tenerensis (crocodile mimic from the Ténéré), and Jobaria tiguidensis (named for Jobar, a legendary creature of the Tuareg nomads and for the cliff near the excavation sites). Suchomimus measures 36 feet long and 12 feet high. The specimen is the most complete known of a peculiar group of fish-eating predators called spinosaurs that lived 100 million years ago. A mounted-cast skeleton of Suchomimus is on display at the Chicago Children’s Museum. Jobaria, a plant-eater, grew to a length of 70 feet, measured 15 feet high at the hip and weighed 20 tons. The animal represents an ancient sauropod lineage that survived and flourished only in Africa during the Cretaceous Period 135 million years ago.

• South American Dinosaur Expeditions

  Argentina, 1988. In his first expedition as leader, Sereno and several Argentine colleagues explore a region of northwestern Argentina known as Ischigualasto. Sereno discovers a skeleton of Herrerasaurus ischigualastensis that allows the first accurate reconstruction of the dinosaur. Herrerasaurus grew to a length of 12 feet and lived 228 million years ago, during the Triassic Period. The dinosaur was named for the late Victorino Herrera, a local artisan who led paleontologists to the first bones, and for the Ischigualasto valley, where it was discovered. A flesh model of Herrerasaurus is on display at the Field Museum in Chicago.

  Argentina, 1991. The return expedition to explore more remote regions of the Ischigualasto valley leads to the discovery of a small skeleton belonging to a new species named Eoraptor (dawn raptor). A contemporary cousin of Herrerasaurus, Eoraptor is the most primitive dinosaur ever found. It measures only three feet from snout to tail tip. A predator, it was armed with razor-sharp teeth and long claws. Ancient volcanic ash beds discovered near these early dinosaurs allow Sereno’s team to determine their age–228 million years old–and date the dawn of the dinosaur era. These discoveries shed light on the roots of the dinosaur family tree and on how and when dinosaurs came to dominate the land.