OXFORD UNIVERSITY, K. TRINAJSTIC
A fresh inspection of a 415 million-year-old fish skull first found in Siberia in 1972 revealed a cartilaginous surprise in its interior, challenging the conventional wisdom that the common ancestor of jawed vertebrates resembled fleshy sharks and not bony salmon, researchers from the University of Oxford and Imperial College London reported this week (January 12) in Nature.
Embedded in rock, the partial skull roof and brain case looked from the outside like they belonged to a bony ray-finned fish. According to new 3-D images the researchers generated with X-ray computed tomography (CT) scans, the skull’s inner features also include canals that can sense changes in surrounding pressure—typical of bony fish. But other features, like the placement of blood vessels in the brain case located above ...
