Haikoucaris measured about 38 mm in body length.[1] The elongated body compose of a semicircular head shield, 13 trunk tergites and presumely a short, spine-like telson.[1][2] The head possess a pair of unstalked eyes, a pair well-developed great appendages, as well as 3 more appendage pairs of unknown detail.[2] Each of the great appendage consists of a 2-segmented peduncle and a 3-segmented claw.[2] Each of the trunk segment possess a pair of biramus appendages that each comprising a leaf-shaped exopod and a possibly 7-segmented endopod.[2]
Paleoecology
Haikoucaris may have been a predator, with its great appendages and exopod suggested to be used for hunting and swimming respectively.[2]
Taxonomy
Within megacheirans, Haikoucaris is generally accepted to be a member of the clade Cheiromorpha alongside Yohoia and Leanchoiliidae.[3][4][5][6]