Myllokunmingia
| Myllokunmingia | ||||||||||||
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Myllokunmingia |
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| Temporal occurrence | ||||||||||||
| Lower Cambrian | ||||||||||||
| 525 to 520 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Myllokunmingia | ||||||||||||
| Shu , Zhang & Han , 1999 | ||||||||||||
Myllokunmingia is a vertebrate from the Lower Cambrian Maotianshan shale in China . The animal has similarities to a modern hagfish and reaches 28 mm in length and 6 mm in height, it is most likely a jawless (primitive fish )
At around 530 million years old, Myllokunmingia is the oldest vertebrate to date to have been found in Cambrian rocks . The fossil has a skull and skeletal structures, which are probably made up of cartilage tissue - comparable to the lampreys , which are also counted among the vertebrates. There are no signs of mineralization of the skeletal elements (biomineralization).
description
The holotype comes from the Chengjiang Fauna Community and was discovered in the Eoredlichia trilobite zone near Haikou near Ercaicun , Kunming , Yunnan Province . The animal has a clearly defined head area, the trunk has a sail-like (1.5 mm) dorsal fin at the front, and a (probably paired) ventral fin lobe further back . There are five or six gill pockets with hemibranchia on the head . In the trunk area, there are 25 muscle segments ( myomers ) on the outside , which are arranged in a backward herringbone pattern. The animal also has a notochord , a pharynx and a digestive tract, which may extend to the rear end. The mouth cannot be clearly made out. A pericardium may also be present. There are no bones to be seen. The tail end is covered by the sediment only in a single find .
Myllokunmingia fengjiaoa (Shu, Zhang & Han) is (so far) the only known species.
Another find from the slate, very similar to Myllokunmingia, is Haikouichthys . There are also several controversial chordata (more primitive hemichordata ).
literature
- Shu et al .: Lower Cambrian vertebrates from south China. Nature 402, 42-46 (November 4, 1999) doi : 10.1038 / 46965
