"Tidal Giant" Roamed Coastal Swamps of Ancient Africa
By John Roach
for National Geographic News
|May 31, 2001|
Researchers have unearthed fossils of what appears to have been the
second largest known creature ever to walk on Earth. The dinosaur, named
Paralititan stromeri weighed in at an estimated 75 tons and
measured as long as 100 feet (30.5 meters).
It dwelled 94 million years ago in mangrove swamps that once covered what is now a remote desert area in western Egypt.
"It was a truly enormous dinosaur by any reckoning," said Joshua Smith, a doctoral student at the University of Pennsylvania in Philadelphia. He headed the research team that found the dinosaur fossils and is the lead author of a paper reporting on the discovery in the June 1 issue of Science.
The partial skeleton of Paralititan included an upper arm bone 1.69 meters (5.5 feet) long. By comparing it with other fossils, the scientists concluded that Paralititan was the second largest dinosaur ever found, exceeded in size only by Argentinosaurus, which lived at the same time in an area of what is now Argentina.
The bones of Paralititan were found in Egypt's Bahariya Oasis, a fossil trove that has remained largely unexplored since early in the 20th century, when German geologist Ernst Stromer discovered four smaller dinosaur species at the site. All of Stromer's fossils were destroyed in 1944 during a World War II attack on Munich by Allied forces.
Former Tropical Swamp
Smith and his colleagues believe that millions of years ago the Bahariya Oasis was a large tropical forestprobably much like the Ten Thousand Islands region of Florida's Everglades National Park, a shallow-water area of tidal flats and channels. The oasis later became desert.
The Paralititan fossils were found in fine-grained sediment full of plant remains and root casts. The researchers also found fossils of turtles, crocodiles, other large sauropods, and three carnivorous dinosaurs the size of Tyrannosaurus rex.
The researchers note in Science that these creatures thrived during a "hothouse" global climate. There was very little difference in temperature between the poles and the equator, and sea levels were highclimatic conditions apparently favorable to a population of large-bodied terrestrial herbivores, such as Paralititan.
"It is possible that the environment we found Paralititan in was among the most productive environments in the world at that time," said Kenneth Lacovara, a geologist at Drexel University in Philadelphia and co-author of the scientific paper.
The discovery of these and other large vertebrate fossils in Egypt lends credence to a theory that Africa and South America were part of the same land mass during the Late Cretaceous period (146 to 65 million years ago), said Thomas Holtz, a vertebrate paleontologist at the University of Maryland in College Park.
Scientists have found groups of vertebrates that were common to South America and Madagascar during the Late Cretaceous, but these same groups have appeared to be missing from Africa.
One possible explanation for the mysterious absence is that Africa may have split apart from South America before the Late Cretaceous. A second explanation holds that the two continents were still attached through the Late Cretaceous, but relatively few dinosaur fossils have been discovered in Africa because research in the area has been limited.
"This discovery is consistent with the second model," said Holtz, adding that Paralititan seems to be closely related to Argentinosaurus.
|© 1996-2008 National Geographic Society. All rights reserved.|