A rare nautilid specimen of Cenoceras sp. is described from the middle part of the Parvadeh Formation (central Iran) bracketing an age between upper Bajocian and middle Bathonian. This is the first record of the genus from the Middle Jurassic of Iran. Additionally, this study also highlights encrustations on the nautilid shell. Three species of serpulid tubeworms (Propomatoceros cf. lumbricalis, Propomatoceros sp., Nogrobs? sp.), a calcareous sabellid Glomerula gordialis and two taxa of cyclostome bryozoans are identified as encrusters on the nautilid shell. The encrustations are used to infer the depositional environment of the nautilid. Additionally, this Iranian association of encrusters is similar to the encrusting fauna recorded globally in the Middle Jurassic.
