Calvipilosa kroegeri
Early Ordovician (Arenigian)
Fezouata Formation
Mecissi-Zagora Region, Draa Valley, Morocco

Big 55mm aculiferan mollusk on 155mm slab. At least four times larger than the largest we have seen before. Great display or study specimen. This slug-like animal with a cap-like shell represents a significant find in the study of molluscs and their origins. Rare

See: Spiny Slugs: New fossil discovery sheds light on mollusk evolution

See: Vinther, J.; Parry, L.; Briggs, D. E. G.; Van Roy, P., Ancestral morphology of crown-group molluscs revealed by a new Ordovician stem aculiferan, Nature,‎ 2017, p. 1–19