Ankylosaurus[nb 1] is a genus of armored dinosaur. Its fossils have been found in geological formations dating to the very end of the Cretaceous Period, about 68–66 million years ago, in western North America, making it among the last of the non-avian dinosaurs. It was named by Barnum Brown in 1908; the only species in the genus is A. magniventris. The genus name means "fused lizard", and the specific name means "great belly". A handful of specimens have been excavated to date, but a complete skeleton has not been discovered. Though other members of Ankylosauria are represented by more extensive fossil material, Ankylosaurus is often considered the archetypal member of its group, despite having some unusual features. Possibly the largest-known ankylosaurid, Ankylosaurus is estimated to have been between 6 and 8 meters (20 and 26 ft) long and to have weighed between 4.8 and 8 metric tons (5.3 and 8.8 short tons). It was quadrupedal, with a broad, robust body. It had a wide, low skull, with two horns pointing backward from the back of the head, and two horns below these that pointed backward and down. Unlike other ankylosaurs, its nostrils faced sideways rather than towards the front. The front part of the jaws was covered in a beak, with rows of small, leaf-shaped teeth farther behind it. It was covered in armor plates, or osteoderms, with bony half-rings covering the neck, and had a large club on the end of its tail. Bones in the skull and other parts of the body were fused, increasing their strength, and this feature is the source of the genus name. Ankylosaurus is a member of the family Ankylosauridae, and its closest relatives appear to be Anodontosaurus and Euoplocephalus. Ankylosaurus is thought to have been a slow-moving animal, able to make quick movements when necessary. Its broad muzzle indicates it was a non-selective browser. Sinuses and nasal chambers in the snout may have been for heat and water balance or may have played a role in vocalization. The tail club is thought to have been used in defense against predators or in intraspecific combat. Ankylosaurus has been found in the Hell Creek, Lance, Scollard, Frenchman, and Ferris formations, but appears to have been rare in its environment. Although it lived alongside a nodosaurid ankylosaur, their ranges and ecological niches do not appear to have overlapped, and Ankylosaurus may have inhabited upland areas. Ankylosaurus also lived alongside dinosaurs such as Tyrannosaurus, Triceratops, and Edmontosaurus.
On a yacht south of the Equator waters, we meet a ruthless tycoon named Thornton Armitage and his family whose daughter's wed to the arrogant Ned Hallet along the trip is a paleontologist Steve who's teaching Thornton's son Billy about dinosaurs. During the voyage, Steve becomes attracted to Thornton's daughter Elaine and they both start to fall in love but all are disrupted by a large typhoon that threatens the yacht and begins to sink evacuating to a nearby submarine the group then finds themselves in a prehistoric land filled with dinosaurs, prehistoric beasts, and exploding volcanoes. Steve decides since he is the dinosaur expert to lead the group through survival but Hallet who is a trigger-happy hunter is jealous of Steve upon leaving the group he hunts down a baby Triceratops and meets his demise at the hand of an angry mother. After encountering many reptilian creatures of this lost world the group must make contact with the outside world before the prehistoric wonder around them is lost to the deadly forces of nature.
