October 16, 2007—An artist's rendering depicts a newly discovered giant dinosaur (left and second from left) lumbering through its habitat some 80 million years ago. (Read full story and watch video.)

Scientists recently unearthed fossils of the 105-foot (34-meter) behemoth—along with a trove of other ancient animals—in the Patagonia region of Argentina, scientists announced yesterday.

The remains are among the most complete ever recovered from a giant dino and provide an in-depth look at the prehistoric beast and its environment, said Jorge Calvo, director of Argentina's Comahue National University Paleontology Center and lead scientist on the research team.

The four-story-tall plant-eater—believed to be a new species—was found alongside fossils of fish, crocodile-like reptiles, a flying pterosaur, and a sickle-clawed meat-eater called a megaraptor.

"The fact that most of the fossils were found in a limited area under a 0.5-meter [1.5-foot] rock layer makes us deduct that all those animals lived in the same epoch," Calvo told the AFP news service.

The wealth of plants and animals found with the dino could allow researchers to piece together its ancient ecosystem with striking detail, said Alexander Kellner, a member of the research team from Brazil's National Museum.

"The accumulation of fish and leaf fossils, as well as other dinosaurs around the find, is just something fantastic," he told the Reuters news service.

"It's like a whole lost world for us."

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