The oldest-known duck-billed dinosaur (hadrosaurid) was found near Flower Mound, in North Central Texas, USA. This fossil, named Protohadros byrdi, dates from the about 95.5 million years ago, much earlier than any other duck-bills.

This plant-eating dinosaur was about 15 to 20 feet (4.6 to 6 m) long and 6 feet (1.8 m) tall at the hips. Its hind legs were larger than the front legs; it could walk on two legs or four. It probably walked on 4 legs while grazing low-lying plants. It as a stiff tail, hoof-like nails on their feet, and a bulky body. It had a toothless beak and many cheek teeth that were used for grinding up tough plant material.

This part of Texas was a warm, humid, wooded marsh during the life of Protohadros byrdi.

Although it has been long believed that hadrosaurs originated in Asia, the new find, Protohadros byrdi, seems to shift the birthplace of hadrosaurs to North America.

Protohadros byrdi was described by paleontologist Jason Head from the Department of Geological Sciences at Southern Methodist University's Dedman College of Humanities and Sciences. His findings were published in the January 1999 issue of the Journal of Vertebrate Paleontology.

Classification
Protohadros byrdi was a hadrosaurid dinosaur, a duck-billed dinosaur.

Hadrosaurids (meaning "bulky lizards") were the family of duck-billed, herbivorous dinosaurs. They were the most common dinosaurs. Hadrosaurs ranged in size from 10 to 40 feet (3 to 12 m) long. They had horny, toothless beaks and cheek teeth in the sides of their jaws. They had stiff tails that were probably used for balance, hoof-like nails on their feet, and bumpy skin. They ran on two legs, holding their tail and head in a horizontal position. They may have walked on all four legs while grazing. Hadrosaurs probably lived near bodies of water, migrating to high ground to lay eggs. It used to be thought that they had webbed hands, but this was an artifact of the fossilization process.

Hadrosaurs are closely related to the Iguanodontids, and are possibly their descendants. Hadrosaurs were Ornithischians (the order of bird-hipped dinosaurs) and Ornithopods ("bird-footed" herbivores with hoof-like feet). Hadrosaurs are divided into two groups, the Hadrodsaurinae (non-crested hadrosaurs) and the Lambeosaurinae (hadrosaurs that had skull crests that connected with their nasal passages).

When Protohadros Lived
Protohadros byrdi lived during the Cretaceous period, about 95.5 million years ago.

Fossils
The skull, some ribs, and foot bones were found in 1994 by paleontologist Gary Byrd. Jason Head analyzed the fossil.

Hadrosaurs fossils have been found in North America, Europe, and Asia.

Fossils Found in Texas
(Including dinosaurs, plesiosaurs, pterosaurs, and ichthyosaurs; * = not a dinosaur.)
Acrocanthosaurus, Alamosaurus, Camptosaurus, Chasmosaurus, Coelophysis, Deinonychus, Dimetrodon*, Edmontosaurus, Hypsilophodon, Iguanodon, Kritosaurus, Ornithomimus, Panoplosaurus, Pleurocoelus, Protohadros byrdi, Quetzalcoatlus*, Shuvosaurus, Stegoceras, Technosaurus, Tenontosaurus, Torosaurus, Tyrannosaurus rex

Reference
Head, J.J. 1998. A new species of basal hadrosaurid (Dinosauria, ornithischia) from the Cenomanian of Texas. Journal of Vertebrate Paleontology 18(December):718.

Related Links
Pages on close relatives, other duck-bills, like Edmontosaurus, Maiasaura, Lambeosaurus, Corythosaurus, and Parasaurolophus.

All about the duck-bills, the hadrosaurids.

Creatures and climate of the Cretaceous period.

Other fossils found in Texas (and other parts of North America).

Chart of geological time.

Enchanted Learning^®
Over 35,000 Web Pages
Sample Pages for Prospective Subscribers, or click below

Click to read our Privacy Policy

E-mail