Vermilituus gregarius is a species of enigmatic, worm-like animal from the Cambrian Period of China.

Vermilituus is superficially similar to tube worms, but the phylogenentic placement of the species is uncertain.

[1] Size variations of V. gregarius on individual vetulicolians suggest that larvae landed on a host organism over an extended period of time.

The locations of these aggregations of V. gregarius reveal insights into the soft tissue anatomy of vetulicolians, which is otherwise enigmatic.

The generic name is a compound word derived from the Latin vermis, meaning "worm," and lituus, a J-shaped instrument resembling the shape of the animal.