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Report: Myllokunmingia fengjiaoa--Chengjiang fauna
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Prof.Shu Degan, Northwest University, China 
Mt. Maotian, Chengjiang, Yunnan |
During the late 1990's, a group of palaeontologists from Northwest University in Xi'an, China and Cambridge University in England, discovered two fossils of the earliest vertebrates ever found. The specimens came from Haikou, 40 km to the west of Chengjiang in the Yunnan Province of South China. The area around Chengjiang is becoming internationally recognised as a key locality for the study of soft-bodied fossils from the Early Cambrian Period, about 530 million years ago. Led by Prof. Degan Shu, director of the Early Life Institute at Northwest University, the group published their discoveries in the international scientific journal Nature on the 4th November 1999.
The origin of vertebrates, which include mammals, birds, reptiles, amphibians and fish, is one of the largest mysteries for evolutionary biology. Clear fossils of the primitive agnathan fish have been long known from the Lower Ordovician Period (~475 million years ago), with more questionable examples from the earlier Cambrian Period (510-545 million years ago). The newly described fossils from Chengjiang Faunas have been clearly identified as agnathans, a discovery that pushes back the fossil record of the vertebrates about 50 million years. |
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Yunnanozoon lividum
Ma'anshan, Chengjiang, Yunnan, People's Republic of China Early Cambrian (about 530 million years ago) Yunnanozoon is the oldest known example of a hemichordate. The phylum (or 'supergroup') Hemichordata is closely associated with the phylum Chordata, which includes the vertebrates along with other groups such as cephalochordates and urochordates. The identification of Yunnanozoon is therefore also significant for the early evolution of chordates and vertebrates. |
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Cathaymyrus diadexus
Ma'anshan, Chengjiang, Yunnan, People's Republic of China Early Cambrian (about 530 million years ago) This is oldest known example of a cephalochordate. The form of Cathaymyrus resembles that of Pikaia from the Middle Cambrian Burgess Shale of Canada, but this animal is about 10 million years older. Some palaeontologists have suggested that the vertebrates, which include humans, evolved from cephalochordates like Cathaymyrus. |
 
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Xidazoon stephanus
Haikou, Kunming, Yunnan, People's Republic of China Early Cambrian (about 530 million years ago) The relationship of Xidazoon to the known animal groups is ambiguous. The anterior of this animal resembles an agnathan fish known as a pipiscid, but the segmented tail-like posterior is more like that of an invertebrate, such as an arthropod. Because of its enigmatic nature, Xidazoon has at present been assigned to the pseudo-phylum "Problematica". Nevertheless, this animal has great importance in the study of the evolution of the primitive deuterostomes and protostomes. Reconstruction is supervised by Prof. Shu Degan. |
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