An early chondrichthyan and the evolutionary assembly of a shark body plan

CT and histology of the single dorsoventrally compressed Gladbachus adentatus specimen UMZC 2000.32 from the Upper Givetian Lower Plattenkalk at approximately 385 Ma reveal a stem chondrichthyan with a mosaic neurocranium, jaws, branchial skeleton, cartilage, scales and teeth; the specimen documents disparity, not a crown-shark ancestor or body-plan FAD.

Gladbachus adentatus is represented by the single compressed specimen UMZC 2000.32 and was recovered on the chondrichthyan stem rather than within the living crown.

UMZC 2000.32 comes from the Upper Givetian Lower Plattenkalk at Unterthal, Bergisch Gladbach, Germany; this occurrence does not define a wider range.

The slab records an aquatic fish body but does not directly preserve diet, prey capture, swimming performance or habitat preference.

CT and histology reveal neurocranium, jaws, branchial skeleton, pectoral girdle, cartilage, scales and teeth in UMZC 2000.32.

The displayed approximately 385 Ma point is the Upper Givetian occurrence of UMZC 2000.32 and not a global chondrichthyan FAD.

The Stem-chondrichthyan evidence route navigation entity is source-linked only to the named specimen, dataset and analysis dossiers already cited by its range ledger. Its displayed span is a study-bounded route or sample envelope, not a biological taxon, ancestor sequence, global FAD/LAD or exact origin interval.