Haikouichthys

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Haikouichthys
Fossil range: Early Cambrian

Artists concept of Haikouichthys ercaicunensis

Kingdom:	Animalia
Phylum:	Chordata
(unranked)	Craniata
Genus:	Haikouichthys

Haikouichthys is an extinct genus of craniate believed to have lived c 530 million years ago, during the Cambrian explosion. Haikouichthys had a defined skull and other characteristics that have lead paleontologists to label it a true craniate.

Cladistic analysis indicates that the animal is probably a primitive agnathan fish or fishlike chordate most closely related to the Lampreys. It is about 2.5cm long and is narrower than the Myllokunmingia, another primitive fish that comes from the same beds. The holotype was found in the Yuansshan member of the Qiongzhusi Formation in the 'Eoredlichia' Zone near Haikou at Ercaicun, Kunming City, Yunnan, China.

The animal has a distinct head and tail. The head has at least six and perhaps nine probable gills. There are a number of segments (myomeres) with rear directed Vs in the tail. There is probably a notochord although only a short segment is preserved in the single known specimen. There is a prominent dorsal fin with fin radials. The fin radials seem to angle "forward" toward the end thought on the basis of internal structures to be the head. This happens with a few modern fish but is an uncommon arrangement. There is a ventral fin fold. There are 13 circular structures along the bottom that may be gonads, slime organs, or something else entirely.

A similar creature from these shales is known as Myllokunmingia.

There is one species Haikouichthys ercaicunensis Luo, Hu & Shu.

1 Popular Culture
2 See also
3 External links
4 References

[edit] Popular Culture

In the first episode of the BBC series Walking With Monsters, Haikouichthys is portrayed as a kind of early fish. In that episode, a school of them attack a wounded Anomalocaris. Later, Haikouichthys is depicted allegedly evolving into the Early Devonian Cephalaspis.