Can be traced back to 550 million years ago, the American state of Arizona appeared "living fossil"-- dinosaur.

CTOnews.com, December 29 (Xinhua) hundreds of dinosaur shrimp have appeared in Arizona in the United States. Although their appearance is very scary, they have survived on Earth for 550 million years and can be regarded as very important "living fossils" for scientific research.

A tourist found the "living fossils" while walking on an Arizona beach on December 23. CTOnews.com learned that the appearance of the dinosaur was little different from that of Devonian fossils, or more than 100 million years before dinosaurs walked the earth. For more details, you can visit here.

Lauren Carter, the chief commentator of Wupatki National Monument, says the dinosaur shrimp is called Triops (three-eyed dinosaur). Its life cycle is not long, about 90 days, and the adult can be 1 inch 3 inches long. After hatching, it grows at about twice the rate of growth in a day. Their larvae undergo multiple shelling (about once a day) and evolve to adults within 30 days.