Friday, June 4, 2010

Long Horned Dinosaur

The beastie is intriguing but more so the comment that this bone yard has evidence of encrustation by sea life. This places the animal in a tidal swamp or riverine delta and a long ways from traditionally assumed upland environments.

I suspect that dinosaur like reptiles are best situated in wetlands with their ample supply of consumable vegetation.  The current fashion is to place them in open plains and semi arid conditions.  That was certainly true for specialized animals perhaps similar to out emus and the like.  Yet for bulky animals such as the theropods and these beasties, cooling needs almost begged settling into a pool of water.

Elephants and hippos use water today for cooling and I suspect these oversized reptiles were likely less efficient at cooling.  Thus the large unfeathered critters had every reason to be in swamps.

It is suggestive and provides a bit of conforming evidence.

Dinosaur Had Horns the Size of Baseball Bats
By Jeanna Bryner, LiveScience Managing Editor
posted: 28 May 2010

A tubby dinosaur sporting horns each the length of a baseball bat roamed what is now Mexico some 72 million years ago.

Remains of the plant-eating dinosaur, now called Coahuilaceratops magnacuerna, were unearthed from the Cerro del Pueblo Formation in Coahuila, Mexico. Fossils belonging to both an adult and juvenile of the species were unearthed at the site.

When alive, the dinosaur would have been about the size of a rhinoceros, weighing 4 to 5 tons (3,600 to 4,500 kilograms), with horns estimated to be 3 to 4 feet long (about 1 meter). The horns are considered the longest of any ceratopsids, a group of plant-eating horned dinosaurs whose members include the famousTriceratops.

Like other horned dinosaurs, Coahuilaceratops probably used its headgear to attract mates and fight with rivals of the same species.

"Being one of the largest herbivores in its ecosystem, adult Coahuilaceratops probably didn't have to worry about large tyrannosaur predators," said researcher Andrew Farke of the Raymond M. Alf Museum in Claremont, Calif.

The new species, announced today, will be detailed in the book "New Perspectives on Horned Dinosaurs" to be released next week by Indiana University Press.

Monster storms

Mark Loewen, a paleontologist with the Utah Museum of Natural History and lead author of the study, described the arid, desert terrain where the dinosaur was recovered as nothing like Mexico during the Late Cretaceous (97 million to 65 million years ago). At that time, due to high global sea levels, the region was a humid estuary with lush vegetation, much like the present-day Gulf Coast.

The high sea level created an interior seaway that split North America into a western landmass called Laramidia and an eastern one called Appalachia.

Coahuilaceratops lived at the southernmost tip Laramidia.

Many dinosaur bones in the area are covered with fossilized snails and marine clams, suggesting the dinosaurs lived adjacent to the seashore.

Ancient ecosystem

In addition to Coahuilaceratops, the research team found remains of two other horned dinosaurs, two duck-bill dinosaurs, as well as the remains of carnivores, including large tyrannosaurs (smaller, older relatives of T. rex) and more diminutive Velociraptor-like predators armed with sickle-claws on their feet.

In fact, some of the sites in the area appear to represent mass death events, perhaps associated with storms such as today's hurricanes that occur in the region.

"Sitting near the southern tip of Laramidia, this region may have been hammered by monstrous storms," said study researcher Scott Sampson, a paleontologist at the Utah Museum of Natural History. "If so, such periodic cataclysms likely devastated miles of coastline, killing off large numbers of dinosaurs."

But that's not how Coahuilaceratops died. "This was found with several individuals, but we don't think a hurricane killed these guys," Loewen told LiveScience. "Hurricanes came through and destroyed some of the dinosaurs. The actual one we're announcing didn't die that way."

In all, the discoveries paint a picture of a diverse, ancient ecosystem strewn with plant- and meat-eating dinosaurs, possibly representing a previously unknown assemblage of species, the researchers say.

"Rather than focusing only on individual varieties of dinosaurs, we are attempting to reveal what life was like in Mexico 72 million years ago, and understand how the unique ecosystem of Mexico relates to ecosystems to the north at the time," Loewen said.

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