Beginning in the 1960s, a rising number of scientists turned to the study of dinosaurs as a career-despite the low pay. Also, more museums and universities developed dinosaur research programs. Since the '60s, the number of known dinosaurs species has more than doubled, and our understanding of dinosaurs greatly increased.
The United States and Canada became home to the most vigorous dinosaur research in the world. The Tyrrell Museum of Paleontology in Alberta is located in the middle of a fertile dinosaur burial ground. Led by Philip J. Currie, Tyrrell researchers found bone beds that apparently were the remains of dinosaur herds. These provided information about growth changes, individual differences, disease, and herd structure.
John R. "Jack" Homer discovered hatchling duckbilled dinosaurs, dinosaur eggs, embryos, and nesting grounds in Montana's Two Medicine Formation. One kind of egg belonged to a duckbilled dinosaur that he and Robert Makela named Maiasaura. Another egg was from a small ornithischian dinosaur that he and David B. Weishampel called Orodromeus. Horner also pioneered new techniques for examining dinosaur fossils, such as CAT-scanning the remains of dinosaur eggs to find embryos. Horner and his team found a Maiasaura bone bed that covered several square miles and contained the remains of at least 10,000 animals.
Farther south, in Utah and Colorado, the late James A. Jensen's work left an enormous amount of material-enough to fill a warehouse. These included remains of the immense plant-eaters Supersaurus, Ultrasauros, and Dystylosaurus, the more modest-size herbivore Cathetosaurus, the carnivore Torvosaurus, and several others. One of Jensen's most productive sites, the Late Jurassic Dry Mesa Quarry, yielded a six-foot-tall pelvis.
In Arizona, New Mexico, and Texas dinosaur-bearing rocks were discovered from Late Triassic to Late Cretaceous. Petrified Forest National Park and its surroundings are of Triassic age and have been studied by Robert A. Long, J. Michael Parrish, and several others. They studied fossils of North America's oldest known dinosaurs. Sankar Chatterjee examined fossils of dinosaurs and related animals from Triassic rocks in Texas. His prize fossil was what may be the oldest known bird.
Spencer G. Lucas and Adrian Hunt started several projects in New Mexico, including a survey of dinosaurs and their locations. The San Juan and Raton Basins contained rocks deposited when the Mesozoic Era ended. In 1947, an American Museum of Natural History field party led by Edwin Colbert discovered an extensive dinosaur burial site at Ghost Ranch, New Mexico. Dozens of skeletons of Coelophysis bauri had become tangled in an ancient stream. In 1989, Colbert published his work on Coelophysis, making it the best-known Late Triassic predatory dinosaur.
In the mid-1980s, the first Alaskan North Slope dinosaur bones were discovered. They were from the duck-billed Edmontosaurus, which stood ten feet tall and were 40 feet long. Scientists speculated that these dinosaurs lived in social groups, or even herds.
In the early 1970s, Robert T. Bakker drew on the work of anatomist Gerhard Heilmann and paleontologist John Ostrom and argued that dinosaurs were not slow moving, but rather warm-blooded, active, and mobile. He also argued that dinosaurs are the direct ancestors of birds, a theory that received further support with new discoveries in the 1990s.
The eastern half of North America has produced few dinosaur fossils. In the 1980s, Paul E. Olsen studied the East Coast from Nova Scotia to New Jersey. He discovered the remains of several new Triassic dinosaurs. Olsen also found evidence of a large asteroid impact near the end of the Triassic, which may have killed other animals and allowed dinosaurs to rise to dominance.
Modern Dinosaur Discoveries in Mexico
In the past, Mexico was not well explored for dinosaurs. From 1968 to 1974, William J. Morris and his colleagues worked in the El Gallo Formation of Baja, California. They collected partial skeletons of the large duckbilled dinosaurs Lambeosaurus laticaudus, which was estimated to be as long as 54 feet. Also collected from the somewhat older La Bocana Roja Formation were the fragmentary remains of Labocania anomala, a heavily built, meat-eating dinosaur. These were the only dinosaurs known from Mexico from more than scraps.
James M. Clark, Rene Hernandez, and other paleontologists worked a site of roughly Middle Jurassic age in Tamaulipas, Mexico. Middle Jurassic dinosaur-bearing rocks are rare; the Mexican site was the first one found in North America. Another Mexican site yielded the remains of Late Cretaceous dinosaurs, especially duckbills.
South America saw an explosion of dinosaur research with the work of Reig and Romer. Jose F. Bonaparte and his colleagues worked in dinosaur-bearing formations in Argentina. One find was a bizarre relative of Diplodocus. This animal evidently had a pair of tall, parallel sails along its neck and back. South American Cretaceous dinosaurs were unusual, having evolved on their own after the continent broke free of Africa in the Late Jurassic Period.
Bonaparte also discovered dinosaurs from the Middle Jurassic in Argentina, including the giant herbivores Patagosaurus and Volkheimeria and the meat-eating Piatnitzkysaurus. This predator strongly resembles the Late Jurassic Allosaurus from North America and may be its closest known ancestor.
Modern Dinosaur Discoveries in China & Europe
In China, the Cultural Revolution of the 1960s stopped most research, but in the mid-1970s there was an explosion of discoveries. Dinosaurs from the Lower Jurassic through the Late Cretaceous are now represented in China by excellent material. Paleontologists from the United States, Canada, and Europe visited China to examine the material and to exchange knowledge. The result was a new "Chinese dinosaur rush."
The Polish-Mongolian Paleontological Expeditions of the late 1960s and early 1970s returned to the Gobi Desert. Zofia Kielan-Jaworowska led the expeditions, and they were rewarded with the discovery of new kids of dinosaurs and more complete remains of other known dinosaurs. Inspired by the success of the Polish scientists, the USSR Academy of Sciences took over field work in the Gobi in the mid-1970s. Almost every year since, the Joint Soviet-Mongolian Paleontological Expeditions unearthed more dinosaur remains. The discoveries inspired the exchange of ideas between Chinese and Western paleontologists.
Eric Buffetaut participated in several recent discoveries. In the late 1970s, while searching for crocodile remains in Thailand, he and coworkers uncovered a huge dinosaur bed in the Upper Jurassic Sao Khua Formation. They found several partial skeletons of large plant-eaters, many scattered teeth of large predators, and the remains of a small meat-eater.
Because much of the Soviet Union is hard to reach, workers rarely discover dinosaurs there. Still, scientists from the Paleontological Institute of the USSR Academy of Sciences began to examine the dinosaur material in their collections. They also organized expeditions to regions south of the Ural Mountains, to the Caucasus, and to eastern Siberia.
Even England still yielded a new dinosaur find or two. Amateur fossil collector William J. Walker chanced upon a huge, foot-long dinosaur claw weathering out of a clay pit in Surrey. This new dinosaur, Baryonyx walkeri, revealed a new family of meat-eating dinosaurs.
Studies by Madrid paleontologist Jose Luis Sanz and his colleagues began to show how much Spain had to contribute to the study of dinosaurs. They found small and large predators, huge long-necked herbivores (including the new species Aragosaurus ischiaticus), small plant-eaters, large plant-eaters (Iguanodon), and armored dinosaurs (Hylaeosaurus). Topping off their work was the discovery at Las Hoyas of a new genus of Early Cretaceous fossil bird. This bird, which was between the "feathered dinosaur" Archaeopteryx and more modern birds, was a key to understanding bird evolution.
In the 1970s, French paleontologists discovered interesting Middle Cretaceous African dinosaurs near the Tenere Oasis in the southern Sahara Desert. Besides claws and teeth identified as Carcharodontosaurus, they found the skeletons of two new dinosaurs related to Iguanodon.
Modern Dinosaur Discoveries in Australia
Ralph Molnar of the Queensland Museum researched dinosaurs in Australia. In 1980, he described Australia's first armored dinosaur, Minmi. With Neville Pledge, he wrote up the small predator Kakuru, which was known only from pieces of fossils. These were the first dinosaurs to be described from Australia since Huene's work in 1932. In 1981, Alan Bartholomai and Molnar wrote up the herbivore Muttaburrasaurus, which is similar to Iguanodon. Muttaburrasaurus was the first almost complete Australian dinosaur ever skeleton found.
Also working in Australia were the husband-and-wife team of Thomas and Patricia Rich. They worked along the southern shore, where they found dinosaur-bearing Early Cretaceous rocks. The fossils were fragmentary and were in hard stone that was difficult to work, but they found enough material to show an unusual dinosaur fauna.
During much of the Cretaceous Period, Australia was close to the South Pole. For two or three months each year, the region was nearly always dark and the winter temperature must have been extremely cold. The dinosaurs that the Riches found were small and active, with oversize eyes that they believed adapted to life in semidarkness.
No paleontologist has doubted that dinosaurs lived in Antarctica during the Mesozoic Era, but it is difficult to find dinosaurs when ice caps two miles thick cover most of the continent. In the 1980s, however, an expedition led by Zulma de Gasparini and her coworkers at Argentina's Museum of La Plata brought back the remains of Antarctica's first known dinosaur. It was an armored form resembling North America's Ankylosaurus. The find was perplexing, since that type of dinosaur is rare.
Some of the most interesting work is not always the discovery of new and unusual dinosaurs. For some paleontologists, the most interesting work is the analysis of fossils gathered years, decades, or even a century ago. We do not know what piece of fossil may lead to new insights into dinosaur behavior or evolution. With the continuing work of dedicated scientists, our knowledge of these wonderful creatures increases almost daily.