Recently in the journal Current Biology, the discovery of the Llanocetus denticrenatus has introduced new knowledge about the evolution of the baleen whales (Mysticeti).
Baleen whales contain baleen in their mouths, which act as a comb to filter out small prey from the seawater. However, new evidence shows early whales had well-developed gums and no baleens.
Not long ago, it was thought that filter feeding had emerged from whales which had teeth. Llanocetus denticrenatus had distinctive grooves on the roof of its mouth, which usually contained blood vessels that supply the baleen. Yet, in ancient whales those grooves cluster around tooth sockets. Thus, the baleen would have been useless and at risk of being crushed.
As a result, the evolutionary transition most likely happened when the teeth had already been lost and whales had switched from biting to sucking in small prey.
Quote from Dr. Felix Marx, paleontologist, Royal Belgian Institute of Natural Sciences, “Instead of a filter, it seems that Llanocetus denticrenatus simply had large gums and, judging from the way its teeth are worn, mainly fed by biting large prey. Even so, it was huge: at a total body length of around 8 m, it rivals some living whales in size.”
Read more about this fascinating story at: www.sci-news.com
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