Abstract:

Recently, the concept and synonyms of the genus Arthricocephalus have been redefined, most species of the traditional
“Arthricocephalus”should be assigned into Oryctocarella, and the Arthricocephalites is the junior synonym of Arthricocephalus. Based
on several specimens of different ontogenetic development stages collected from Zila Village, Huayuan County of northwestern Hunan,
this study shows that the different thoracic segments may be accounted for different development stages, but not the interspecific
variations. Furthermore, several species have been reassigned into Arthricocephalus chauveaui Bergeron 1899, and the intraspecific
vitiations within the genus have been discussed. The morphology and stratigraphical information of Arthricocephalus with other
oryctocephlid trilobties have been compared and their evolutionary relationships have also been discussed in the current study.

Key words: Arthricocephalus, intraspecific variation, ontogeny, Balang Formation, Cambrian, northwestern Hunan.