krih-TAY-shəs) is a
geological period that lasted from about 145 to 66
million years ago (Mya). It is the third and final period of the
era, as well as the longest. At nearly 80 million years, it is the longest geological period of the entire
Phanerozoic. The name is derived from the Latin
chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation Kreide.
The Cretaceous was a period with a relatively warm
climate, resulting in high
eustatic sea levels that created numerous shallow
inland seas. These oceans and seas were populated with now-
dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of
birds appeared. During the Early Cretaceous,
flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread
gymnosperm groups. (
Selected article on the Cretaceous world and its legacies
that lived in
period, between about 72 and 70 million years ago. The only
is Carnotaurus sastrei
. Known from a single well-preserved skeleton, it is one of the best-understood theropods from the
. The skeleton, found in 1984, was uncovered in the
of Argentina from rocks of the
La Colonia Formation
is a derived member of the
, a group of large theropods that occupied the large
in the southern Landmasses of
during the late
Carnotaurus was a lightly built,
bipedal predator, measuring 8 to 9 m (26 to 30 ft) in length and weighing at least 1 metric ton (0.98 long tons; 1.1 short tons). The skeleton is preserved with extensive skin impressions, showing a mosaic of small, non-overlapping scales. The mosaic was interrupted by large bumps that lined the sides of the animal, and there are no hints of feathers. The distinctive horns and the muscular neck may have been used in fighting
conspecifics. The feeding habits of Carnotaurus remain unclear: some studies suggest the animal was able to hunt down very large prey such as
sauropods, while other studies find it preyed mainly on relatively small animals. Carnotaurus was well adapted for running and was possibly one of the fastest large theropods. (
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Selected article on the Cretaceous in human science, culture or economics
Edward Drinker Cope
(July 28, 1840 – April 12, 1897) was an American
, as well as a noted
. Cope distinguished himself as a child prodigy, publishing his first scientific paper at the age of nineteen. Cope later married and moved from
Haddonfield, New Jersey
, although Cope would maintain a residence and museum in Philadelphia in his later years.
Cope had little formal scientific training, and he eschewed a teaching position for field work. He made regular trips to the American West prospecting in the 1870s and 1880s, often as a member of
United States Geological Survey teams. A personal feud between Cope and paleontologist
Othniel Charles Marsh led to a period of intense fossil-finding competition now known as the
Bone Wars. Cope's financial fortunes soured after failed mining ventures in the 1880s. He experienced a resurgence in his career toward the end of his life before dying in 1897.
Cope's scientific pursuits nearly bankrupted him, but his contributions helped to define the field of American paleontology. He was a prodigious writer, with 1,400 papers published over his lifetime, although his rivals would debate the accuracy of his rapidly published works. He discovered, described, and named more than 1,000 vertebrate species including hundreds of fishes and dozens of dinosaurs. His proposals on the origin of mammalian molars and for the gradual enlargement of mammalian species over geologic time ("
Cope's Law") are notable among his theoretical contributions. (
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Current Cretaceous FACs - none currently