Pachycephalosaurus


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Pachycephalosaurus

(păk'ĭsĕf'əlōsôr`əs) [Gr., = thick-headed lizard], bipedal herbivorous dinosaurdinosaur
[Gr., = terrible lizard], extinct land reptile of the Mesozoic era. The dinosaurs, which were egg-laying animals, ranged in length from 2 1-2 ft (91 cm) to about 127 ft (39 m).
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 of the late Cretaceous period, approximately 68–65 million years ago. Its distinguishing characteristic was a very heavy dome-shaped skull that was up to 10 in. (25 cm) thick; the skull was covered with bumps. Because the top vertebrae were able to lock in place, scientists have theorized that the head was used as a battering ram, perhaps to establish dominance within a herd. The mouth was beaked and the jaws held leaf-shaped cheek teeth. The eyes were placed in a way that made it capable of binocular vision, and Pachycephalosaurus is believed to have had an acute sense of smell. Because of a dearth of skeletal specimens, other characteristics of this genus can be surmised only from related dinosaurs. Fossils have been found in Montana, South Dakota, and Wyoming. Pachycephalosaurus, along with Stygimoloch and Homalocephale, belongs to the group of ornithischian dinosaurs called pachycephalosaurs, or bone-headed dinosaurs.
References in periodicals archive ?
Pachycephalosaurus Large and unusual "thick-headed" dinosaurs which grew to be about 5 m (16 feet) long.
Pachycephalosaurus (PACK-ih-SEF-uh-luh-SAW-rus) skulls were thick and bony.
These include Wild Striders, Pachycephalosaurus and the deadly and powerful Tyrannosaurus Rex.
The confirmed dinosaurs featuring in the movie include the Tyrannosaurus Rex, Velociraptors, Triceratops, Gallimimus, Pachycephalosaurus
The robotic dinosaurs currently on site include the mighty T-Rex, a baby T-rex, a Parasaurolophus, a Pachycephalosaurus, an Apatosaurus, a Utahraptor, and a Velociraptor.
Confirmed for auction are: Princess Diana's Swan Lake Diamonds, made for the late Princess by the Royal Family's Crown Jeweler; the world's only known fossilized skeleton of the 65-million-year-old bizarre dinosaur known as Pachycephalosaurus wyomingensis ("Pachy"); Vostak 3KA2, the world's first spacecraft designed for human spaceflight to successfully orbit and return to Earth, carrying a dog and a mannequin; the world's only postmarked letter to survive the Titannic, from young survivor Clear Annie Cameron to her sister; the only privately owned handwritten copy of Clement Moore's 177-year-old classic "A Visit from St.