Did Shark Skeletons Used to Have Bones?

posted: 06/01/15
by: SharkWeek.com Staff
Grey Reef Shark near coral reef and plants, Sudan.

Modern sharks and rays are known for their signature cartilaginous skeletons, but a new study provides compelling evidence that sharks evolved from an ancestor equipped with a more bony skeleton.

According to Flinders University paleontologist Professor John Long, a 380-million-year-old fossil contains trace amounts of calcified bone -- in addition to a largely cartilaginous skeleton. The fossil is believed to represent a shark caught in a transitional evolutionary stage between a more bony frame and modern-day cartilaginous skeleton.

"It's almost a missing link condition showing that early sharks had a lot more bone in their skeleton, and that just before modern sharks evolved they lost the bone, with only the soft cartilage remaining," remarked Long.

The discovery also casts doubt on a long-held belief that fish with bony skeletons are more advanced than the cartilaginous sharks and rays; in fact, the exact opposite may be true.

Long's research is published in the open-access journal PLOS One. Click here to read the full study

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