Ozarcus

[1] The holotype fossil, AMNH FF20544 (formerly labelled as OUZC 5300), was a warped yet three-dimensionally-preserved skull with gill baskets that was discovered by G. K. Mapes.

Each branchial arch starts with basibranchial and hypobranchial bones along the lower midline of the throat, linking upwards tobackwards-leaning ceratobranchials, then forwards-leaning epibranchials, and finally blocky pharyngobranchials.

Unlike modern chondrichthyans, the first four branchial arches have two pairs of pharyngobranchials which bend forwards to form a solid roof to the gill cavity, conditions akin to the two sets (infra- and supra-pharyngobranchials) of osteichthyans.

[1] The initial description of Ozarcus tentatively placed it as a member of the family Falcatidae, based on its small teeth similar to Falcatus and Damocles.

[3] In contrast, later papers placed Ozarcus (represented by specimen FMNH PF 13242) as the sister taxon to Dwykaselachus[3] or close to the base of Symmoriiformes, far away from the falcatid Damocles.