Daily dinosaur: Deinonychus

Deinonychus ( /daɪˈnɒnɨkəs/ dy-non-i-kəs; Greek: δεινός, 'terrible' and ὄνυξ, genitive ὄνυχος 'claw') was a genus of carnivorous dromaeosaurid dinosaur. There is one described species, Deinonychus antirrhopus. This 3.4 meter (11 ft) long dinosaur lived during the early Cretaceous Period, about 115–108 million years ago (from the mid-Aptian to early Albian stages). Fossils have been recovered from the U.S. states of Montana, Wyoming, and Oklahoma, in rocks of the Cloverly Formationand Antlers Formation, though teeth that may belong to Deinonychus have been found much farther east in Maryland.

Paleontologist John Ostrom's study of Deinonychus in the late 1960s revolutionized the way scientists thought about dinosaurs, leading to the "dinosaur renaissance" and igniting the debate on whether dinosaurs were warm-blooded or cold blooded. Before this, the popular conception of dinosaurs had been one of plodding, reptilian giants. Ostrom noted the small body, sleek, horizontal, posture, ratite-like spine, and especially the enlarged raptorial claws on the feet, which suggested an active, agile predator.^[1]

"Terrible claw" refers to the unusually large, sickle-shaped talon on the second toe of each hind foot. The fossil YPM 5205 preserves a large, strongly curved ungual. In life, archosaurs have a horny sheath over this bone which extends the length. Ostrom looked at crocodile and bird claws and reconstructed the claw for YPM 5205 as over 120 millimetres (4.7 in) long.^[1] The species name antirrhopus means “counter balance”, which refers to Ostrom's idea about the function of the tail. As in other dromaeosaurids, the tail vertebrae have a series of ossified tendons and super-elongated bone processes. These features seemed to make the tail into a stiff counterbalance, but a fossil of the very closely related Velociraptor mongoliensis (IGM 100/986) has an articulated tail skeleton that is curved laterally in a long S–shape. This suggests that, in life, the tail could bend to the sides with a high degree of flexibility.^[2]

In both the Cloverly and Antlers formations, Deinonychus remains have been found closely associated with those of the ornithopod Tenontosaurus. Teeth discovered associated with Tenontosaurus specimens imply it was hunted or at least scavenged upon by Deinonychus.

http://en.wikipedia.org/wiki/Deinonychus

Daily dinosaur: Deinosuchus

Deinosuchus (pronounced /ˌdaɪnəˈsjuːkəs/ dy-no-sew-kəs) is an extinct relative of the alligator that lived 80 to 73 Ma (million years ago), during the Late Cretaceous period. The name translates as "terrible crocodile" and is derived from the Greek δεινός/deinos ("terrible") andσουχος/soukhos ("crocodile"). The first remains were discovered in North Carolina (United States) in the 1850s, but it was not until 1909 that the genus was named and described. Additional fragments were discovered in the 1940s and were later incorporated into an influential, though inaccurate, skull reconstruction at the American Museum of Natural History. Knowledge of Deinosuchus remains incomplete, but better cranialmaterial found in recent years has expanded scientific understanding of this massive predator.

Although Deinosuchus was far larger than any modern crocodile or alligator—measuring up to 12 m (40 ft) and weighing up to 8.5 metric tons (9.4 short tons)—its overall appearance was fairly similar to its smaller relatives. It had large, robust teeth that were built for crushing, and its back was covered with thick semispherical osteoderms. One study indicates that Deinosuchus may have lived for up to 50 years, growing at a similar rate to that of modern crocodilians, but maintaining this growth over a much longer period of time.

Deinosuchus fossils have been found in ten U.S. states, as well as northern Mexico. It lived on both sides of the Western Interior Seaway, and was an opportunistic apex predator in the coastal regions of eastern North America. Deinosuchus reached its largest size in its western habitat, but the eastern populations were far more abundant. Opinion remains divided as to whether these two populations represent separatespecies. Deinosuchus was probably capable of killing and eating large dinosaurs. It may have also fed upon sea turtles, fish, and other aquatic and terrestrial prey.

http://en.wikipedia.org/wiki/Deinosuchus

weekly fossil: Jane

Jane is the nickname given to a fossil specimen of small tyrannosaurid dinosaur (Nanotyrannus lancensis or a juvenile Tyrannosaurus rex), officially known as BMRP 2002.4.1, discovered in the Hell Creek Formation in southern Montana.

After four years of preparation, Jane was put on display at Rockford, Illinois' Burpee Museum of Natural History as the centerpiece of an exhibit called "Jane: Diary of a Dinosaur." Paleontologists who support the theory that Jane represents a juvenile believe the tyrannosaur was approximately 11 years old at its time of death, and its fully restored skeleton measured 6.5 metres (21.5 ft) long, about half as long as the largest known complete T. rex specimen, nicknamed "Sue," which measures 13 m (42.6 ft) long. The weight of the Jane specimen in life was probably nearly 680 kg (1,500 lbs). Its large feet and long legs indicate it was built for speed and could possibly run as fast as 20–30 miles per hour. Its lower jaw has 17 curved, serrated teeth.

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Daily dinosaur: Stegosaurus

Stegosaurus ( /ˌstɛɡɵˈsɔrəs/) is a genus of stegosaurid armored dinosaur from the Late Jurassic period (Kimmeridgian to early Tithonian) in what is now westernNorth America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well.^[1] Due to its distinctive tail spikes and plates, Stegosaurus is one of the most recognizable dinosaurs, along with Tyrannosaurus, Triceratops, Diplodocus, and Apatosaurus. The nameStegosaurus means "roof lizard" (sometimes put as "covered lizard", but in the sense that a roof covers a building) and is derived from the Greek στέγος-, stegos-("roof") and σαῦρος, -sauros ("lizard").^[2] At least three species have been identified in the upper Morrison Formation and are known from the remains of about 80 individuals. They lived some 155 to 150 million years ago, in an environment and time dominated by the giant sauropods Diplodocus, Camarasaurus, andApatosaurus.^[3]

A large, heavily built, herbivorous quadruped, Stegosaurus had a distinctive and unusual posture, with a heavily rounded back, short forelimbs, head held low to the ground and a stiffened tail held high in the air. Its array of plates and spikes has been the subject of much speculation. The spikes were most likely used for defense, while the plates have also been proposed as a defensive mechanism, as well as having display and thermoregulatory (heat control) functions. Stegosaurus was the largest of all the stegosaurians (bigger than genera such as Kentrosaurus and Huayangosaurus) and, although roughly bus-sized, it nonetheless shared many anatomical features (including the tail spines and plates) with the other stegosaurian genera.
http://en.wikipedia.org/wiki/Stegosaurus