.:[Dinosaur Planet]:. Dinosaur news, facts and general discussion.

[Kate]

Don't tell me that you have never been facinated by those huge creatures that roamed the Earth over 65 million years ago! Want to find out more? How they lived? How they ate, behaved and had sex? How they went extinct? All these questions are slowly being answered by palaentologists!

This thread is for sharing Dinosaur and/or ancient creatures (that lived before that close of the recent Ice Age) related news, fact and other tidbits. You are more then welcome to post!

Anyway, here's an very recent new discovery related to T. rex from Scientific American:

Growth Study Shows T. Rex Teens Would Have Been a Handful

It's hard to imagine the king of the dinosaurs as an uncoordinated teenager, but recent analysis of the fossil record shows that Tyrannosaurus rex, one of the largest meat-eaters to ever roam the land, grew nearly five pounds a day between ages 14 and 18. This growth spurt accounted for more than 70 percent of its adult mass.

A full-grown T. rex weighed in excess of five tons--15 times more than a polar bear, the largest living terrestrial carnivore. Paleontologists have long wondered how, exactly, T. rex attained its great size. "If T. rex grew as a reptile, it would have taken over a 100 years for it to reach its maximum size," says Gregory M. Erickson of Florida State University.

But the new research, published today [12.08.2004.] shows that T. rex came to tower over its nearest cousins through an accelerated growth stage. Erickson and his colleagues etermined the age-at-death of seven T. rex individuals, as well as 13 specimens of three smaller tyrannosaurid species that lived during an earlier period, by counting bone rings in their fossilized ribs, fibulas and hip bones. Similar rings in modern day reptiles reflect an annual cycle in activity and therefore reveal the age of the organism, just as rings in trees do. From this method, the scientists found that the most senior tyrannosaurid in their sample was just 28 years old.

The team also estimated the body mass of the dinosaurs at the time of death by measuring the circumference of the weight carrying femur. The growth curves of all four tyrannosaurid species showed a spell of exponential weight gain, beginning around the 15th year of life and tailing off four years later. But with growth rates of around a pound a day, the relatives of T. rex only ended up reaching a fourth of its size.

What kind of appetite would one of these T. rex teens have had? Erickson doesn't know exactly, but, he says, "If Purina made T. rex chow, it would take a whole lot of bags." --Michael Schirber
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Discuss away!

[Kate]

Fossil find proves dinosaurs looked after their babies
By Steve Connor
09 September 2004

The mystery of whether dinosaurs were indifferent parents or cared for their young may have been solved by a discovery in China.

More than 100 million years ago an adult dinosaur was buried alive while still trying to protect a clutch of 34 offspring. The case of the parrot lizard dinosaur, psittacosaurus, could be the first in which a dinosaur was clearly showing a degree of parental care beyond guarding a nest of eggs or a clutch of its newly hatched offspring, scientists said.

An analysis of the fossilised skeletons of the young psittacosaurus suggest they could have been several months old. They were physically old enough to fend for themselves but still seemed to need their mother.

A study of the fossils, published in the journal Nature , suggests they were milling together as a family group when they were killed by a sudden mudslide. "The psittacosaurus aggregation provides compelling evidence for post-hatching care among dinosaurs," says the team of scientists from the Dalian Natural History Museum in China and Montana State University in Bozeman.

The argument over whether or not dinosaurs were doting parents has raged for decades. Until recently only birds and mammals were thought to exhibit true parental care.

However, in the 1970s naturalists discovered that crocodiles helped their young to hatch and carried them to water. Then in the 1980s scientists found that a dinosaur they had dubbed oviraptor - the egg-stealer - because its remains were found near a nest, had been trying to incubate the eggs, rather than steal them.

Subsequent discoveries of fossilised eggs and nests in America and Mongolia suggest that many dinosaurs may have cared for their young after hatching. Some laid eggs in earth nests scooped in the soil and returned to feed the young after they emerged.

Other studies suggest that some of the legs of some dinosaur young were too weak for them to roam very far from a nest, which suggests that parents brought food back for them at least in the first days after hatching.

However, the latest find suggests that parental care may have extended beyond the stage of a nest full of newly hatched young. At least some dinosaurs may have behaved more like birds in terms of parental care than today's lizards, which rarely take part in raising or caring for their young.

Source: Independent News, UK