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How did CT scans help identify the fossil chimaera Dwykaselachus oosthuizeni?
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chondrichthyan
Southern stingrays (Dasyatis americana or Hypanus americanus) are found in the western Atlantic Ocean.
The fossil specimen Dwykaselachus oosthuizeni, discovered in South Africa's Karoo region, was initially identified as a member of the Symmoriidae, a group of extinct sharks known for their unusual dorsal fin spines.1
However, computerized tomography (CT) scans were instrumental in reclassifying the specimen. By providing a detailed internal view of the fossil, the scans revealed that the creature possessed a braincase and various other cranial features that more closely resemble those of modern chimaeras than those of sharks. This technological insight allowed paleontologists to look past the external sharklike appearance and identify the specimen as an early representative of the chondrichthyan subclass Holocephali.1