Taxonomy

Phylum: Lobopodia

Class: uncertain

Order: uncertain

Family: Hallucigeniidae

Genus: Hallucigenia

Specie: H.fortis

Description: 

The length of a complete specimen is estimated to be about 2.2 cm.A distinctly expanded head is ellipsoidal in shape, separated from the trunk by a sharp constriction and covered by a pair of thin sclerites.However, the latter finding has not been universally accepted.A pair of lateral eyes is situated dorsolaterally on the head, each of which is suggested to consist of two to three visual units.The trunk is cylindrical with smooth margins and carries seven pairs of long, thorn‐shaped spines dorsolaterally, each corresponding to a pair of slender, annulated, and flexible legs situated ventrally. Another two pairs of even longer and slender legs are present in front of the first pair of spines, and one more pair of legs is also observed behind the last pair of spines. Each leg may have two terminal claws. Fine annulations are observed on the surface of some parts of the trunk and legs. The trunk tapers posteriorly, with a tail behind the last pair of legs. Short sections of the gut are preserved in some specimens.H. fortis might have led an epibenthic, crawling mode of life. The first two pairs of appendages are morphologically differentiated and might have performed a sensory function, while the posterior pairs are undifferentiated legs for locomotion.

Age & Localities

Age: Cambrian Series 2, Stage 3, Eoredlichia-Wutingaspis Zone

Principal localities: Chengjiang biota (Yu’anshan Member of Chiungchussu Formation), eastern Yunnan Province, China