The archaeopriapulida are a group of priapulid-like worms known from Cambrian lagerstatte. The group is ancestral but very similar to the modern Priapulids. It is unclear whether it is mono- or polyphyletic. Despite a remarkable morphological similarity modern cousins, they fall outside of the priapulid crown group, which is not unambiguously represented in the fossil record until the Carboniferous. They are probably closely related or paraphyletic to the palaeoscolecids; the relationship between these basal worms is somewhat unresolved.