Tuesday, December 19, 2006
From The Hankyoreh (Korea): An international team supported by the Gyeonggi provincial government has excavated a rare dinosaur fossil in the Gobi Desert in Mongolia.
Hwaseong City in Gyeonggi Province and an international dinosaur excavation team led by Lee Yung-nam, a researcher of the Korea Institute of Geoscience and Mineral Resources, said on December 17 that they had excavated 8-kilogram fossil of the Tarbosaurus*. The Tarbosausus is an ancestor of the Tyrannosaurus.
This is the first time that an entire fossil of the Tarbosaurus, which lived during the Cretaceous** period of the Mesozoic era about 80 million years ago, has been found. The academic community thinks that with the find, it can accurately confirm for the first time what the rare dinosaur looked like. Its entire appearance has not yet been confirmed due to the fact that fossils of its pelvis and tail region have not been found until now.
In addition, the team found a gastrolith*** - a stone in the abdominal cavity that aided digestion - in the fossil, which marks the first time this stone has been found in the remains of a carnivorous dinosaur.
Continued at "Rare dinosaur fossil unearthed by Korea-led team"
The following notes on Tarbosaurus, the Cretaceous Period, and Gastroliths are taken from Wiki:
*Info on Tarbosaurus:
Tarbosaurus, meaning 'Terror Lizard' (from the Greek tarbos meaning 'fright', 'alarm', 'terror' (interestingly it can also mean 'awe' or 'reverence') and saurus meaning 'lizard'), was a member of the dinosaur family of tyrannosaurids, which flourished during the early Maastrichtian of the Late Cretaceous Period. It is closely related to the genus (and perhaps is indistinct from) Tyrannosaurus. (More)
**Info on Cretaceous:
The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i.e. from 145.5 +- 4.0 million years ago (Ma)) to the beginning of the Paleocene epoch of the Tertiary Period (about 65.5 +- 0.3 Ma). As the longest geological Period, the Cretaceous constitutes nearly half of the Mesozoic. The end of the Cretaceous defines the boundary between the Mesozoic and Cenozoic eras.
The Cretaceous (from Latin creta meaning 'chalk') as a separate period was first defined by a Belgian geologist Jean d'Omalius d'Halloy in 1822, using strata in the Paris basin and named for the extensive beds of chalk (calcium carbonate deposited by the shells of marine invertebrates, principally coccoliths), found in the upper Cretaceous of the continental Europe and the British Isles (including the White Cliffs of Dover). (More)
***Info on Gastroliths:
Gastroliths ('stomach stones' or 'gizzard stones') are rocks, which are or have been held inside the digestive tract of an animal. Among living vertebrates, gastroliths are common among herbivorous birds, crocodiles, seals and sea lions. Domestic fowl, for instance, require access to 'grit', for the purpose of food-grinding. Gastroliths are retained in the very muscular gizzard and serve the masticatory function of teeth, in an animal without suitable grinding teeth. The grain size of the gastrolith depends upon the size of the animal and its special needs. Particles as small as sand and stones the size of cobbles or greater have been found.
Some extinct animals, such as bird-like theropod dinosaurs, appear to have used stones to grind tough plant matter. Gastroliths have only rarely been found in association with fossils of sauropod dinosaurs and a trituration of their food with the stones is not plausible. Aquatic animals, such as plesiosaurs, may have used them as ballast, to help balance themselves or to decrease their buoyancy, as crocodiles do. More research is needed, to understand the function of the stones in aquatic animals. While some fossil gastroliths are rounded and polished, many stones in living birds are not polished at all. Gastroliths associated with dinosaur fossils can be several kilograms in weight. Stones swallowed by ostriches can also reach a length of more than 10 cm. (More)