Rare Chinese fossil teeth have changed scientists' beliefs about the evolution of vertebrates. An international team of scientists has found toothed fish remains that date back 439 million years, which suggests that the ancestors of modern chondrichthyans (sharks and rays) and osteichthyans (ray- a
Volumetric reconstruction of a tooth whorl viewed from its lingual side . The specimen is just over 2 mm in length. Credit: Zhu, et al.An international team of scientists has found toothed fish remains that date back 439 million years, which suggests that the ancestors of modern chondrichthyans and osteichthyans originated far earlier than previously believed.
The discovery indicates that the well-known jawed vertebrate groups from the so-called “Age of Fishes” were already established some 20 million years earlier. For the researchers, the key to reconstructing the growth of the whorls was two specimens at an early stage of formation, easily identified by their noticeably smaller sizes and fewer teeth. A comparison with the more numerous mature whorls provided the paleontologists with a rare insight into the developmental mechanics of early vertebrate dentitions.
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