In a paper published in Nature, researchers have assembled parts of the skull of Eriptychius americanus, a 455 million-year-old fish fossil. This fossil provided a new insight into how vertebrates evolved to preserve their brains.

Research has revealed that the jawless fish found in ancient strata in the American state of Colorado had a skull different from any previously found. This fossil is said to fill a gap of 100 million years in the evolutionary history of the vertebrate skull.

Scientists have reconstructed a detailed three-dimensional representation of Eriptychius' skull using computed tomography (CT). This is the first time such an extensive reconstruction has been done on a specimen collected in the 1940s, originally described in the 1960s. The reconstruction is housed at the Field Museum of Natural History in Chicago.

This fossil fish had discrete, independent cartilage surrounding the brain, unlike the solid bone or cartilage structure of the jawed and jawless fish that followed it. While later species have a fully connected cage of cartilage surrounding the brain, these results suggest that the early evolution of structures separating the brain from the rest of the head may have started with Eriptychius.

Makalenin başyazarı Dr. Richard Dearden, “Görünüşe bakılırsa, Eriptychius fosillerin en güzeli değil. Ancak modern görüntüleme tekniklerini kullanarak eşsiz bir şeyi koruduğunu göstermeyi başardık: Fosil kayıtlarındaki üç boyutlu olarak korunmuş en eski omurgalı kafası. Bu, nihayetinde insanlar da dahil olmak üzere tüm omurgalıların kafatasının evrimine ilişkin anlayışımızdaki büyük bir boşluğu dolduruyor.” diyor.