An artistic illustration of the Nagatitan , the largest dinosaur discovered in Southeast Asia. Patchanop Boonsai hide caption toggle caption Patchanop Boonsai Researchers have identified a new species of dinosaur in Thailand, the largest found in Southeast Asia. It would have been about 90 feet long and weighed some 30 tons, according to research published on Thursday in the journal Scientific Reports . That's the weight of more than four large African savanna elephants, or more than three times the weight of a Tyrannosaurus rex . "One of the many features that we're kind of excited about is the size of this dinosaur," says Thitiwoot Sethapanichsakul, a Ph.D. student at University College London who is the lead author on the research paper. The sauropod — an herbivore with a long neck and tail — comes from the late Early Cretaceous period, some 100 to 120 million years ago, Sethapanichsakul says, and falls somewhere in the "upper middle" range of the largest dinosaurs ever discovered.…