T. Rex Relative Fills Evolutionary Gap

Reconstructed body silhouettes of three tyrannosaurs, showing where Xiongguanlong falls in the spectrum of body sizes in this lineage. Dilong on the left is 125 million years old and the smallest known tyrannosaur. Xiongguanlong, shown in grey, is much larger, but is still dwarfed by T. rex, shown on the right. Credit: M. Donnelly/The Field Museum

From Live Science:

A Tyrannosaurus rex ancestor and an ostrich-mimic have emerged as two new dinosaur species found among a treasure trove of skeletons in China's Gobi Desert.

The T. rex relative had a mouthful of 70 teeth, and stood 5 feet tall at the hip while weighing almost a third of a ton. Scientists say that its discovery helps fill in a "missing link" in the giant carnivore's evolution.

However, the earlier dinosaur "was still a fly weight predator compared to its heavy-weight relatives," said Peter Makovicky, curator of dinosaurs at the Field Museum in Chicago. The Field Museum houses the largest known T. rex specimen, named Sue, which stood at nearly 14 feet tall at the hips and weighed between 6 and 7 tons.

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