1979, when Walcott re-examined the fauna of Burgess shale, the paleontologist Simon Conway Mauriz classified Picea as chordates, because it has a very primitive phylum of protozoa, which may be the earliest ancestor of vertebrates today.

The average length of picking up insects is only 5 cm. It can swim out of the water with its body and wide tail fin. Insect pickers can filter substances in water when swimming. At present, only 60 insect-picking specimens have been found.

Scientists from the University of Cambridge, England, used the latest technology to study the 1 14 Piccaja leptospira fossils found in Burgess shale in Canadian Rocky Mountains, and found that Piccaja leptospira 505 million years ago was the ancestor of modern vertebrates, including humans. This discovery ended the debate for more than a decade: whether Pikettsia belongs to chordates. This research result was published in the latest issue of Biological Review. Simon Conway Morris, the lead author of the research paper published in Biological Review, said: "Sarcoidosis is the conclusive evidence that we have been looking for for for a long time. The discovery of sarcomere, nerve cord, notochord and vascular system proves that Piccaja is the most primitive chordate animal on earth. "