English: Pituriaspis (Pituriaspida). Pituriaspids are mainly known by Pituriaspis, from the Devonian of Australia. As a whole, their headshield is quite similar to that of osteostracans, though devoid of a naso-hypophysial opening. The mouth, gill openings and presumably the nasal aperture were all situated on the ventral side of the head. Well-developed paired fins attached on either sides of the headshield. The only diagnostic feature of pituriaspids is an enigmatic pit adjacent to the eyes.