- Aug 8, 2012
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Ohh No! Not another transitional fossil!!!
Rivaling the evolution of feathers in dinosaurs, one of the most extraordinary transformations in the history of life was the evolution of baleen -- rows of flexible hair-like plates that blue whales, humpbacks and other marine mammals use to filter relatively tiny prey from gulps of ocean water. The unusual structure enables the world's largest creatures to consume several tons of food each day, without ever chewing or biting. Now, Smithsonian scientists have discovered an important intermediary link in the evolution of this innovative feeding strategy: an ancient whale that had neither teeth nor baleen.
The first whales used teeth to chew their food; a characteristic passed on from their land-dwelling ancestors. In the absence of clear evidence, it had been hypothesized that baleen whales went through a transitional stage where teeth may have coexisted with baleen.
A re-examination of Maiabalaena nesbittae, a 33-million-year-old whale fossil originally found in the 1970s, has established that there was no direct transition from teeth to baleen filter feeding. Instead Maiabalaena used a sucking action to take up small fish and squid. A CT scan indicated that Maiabalaena’s upper jaw was too thin and narrow to support baleen. Throat muscle attachment points also indicate strong cheeks and a retractable tongue needed to develop the sucking power for feeding.
This finding is significant in that it adds a major transitional form to the series describing whale evolution. It also provides new insight by showing that whale evolution could proceed without requiring either teeth or baleen.
Read more at:
Whales lost their teeth before evolving hair-like baleen in their mouths: Newly described fossil whale in museum collections reveals a surprising intermediate step in their evolution
OB
Rivaling the evolution of feathers in dinosaurs, one of the most extraordinary transformations in the history of life was the evolution of baleen -- rows of flexible hair-like plates that blue whales, humpbacks and other marine mammals use to filter relatively tiny prey from gulps of ocean water. The unusual structure enables the world's largest creatures to consume several tons of food each day, without ever chewing or biting. Now, Smithsonian scientists have discovered an important intermediary link in the evolution of this innovative feeding strategy: an ancient whale that had neither teeth nor baleen.
The first whales used teeth to chew their food; a characteristic passed on from their land-dwelling ancestors. In the absence of clear evidence, it had been hypothesized that baleen whales went through a transitional stage where teeth may have coexisted with baleen.
A re-examination of Maiabalaena nesbittae, a 33-million-year-old whale fossil originally found in the 1970s, has established that there was no direct transition from teeth to baleen filter feeding. Instead Maiabalaena used a sucking action to take up small fish and squid. A CT scan indicated that Maiabalaena’s upper jaw was too thin and narrow to support baleen. Throat muscle attachment points also indicate strong cheeks and a retractable tongue needed to develop the sucking power for feeding.
This finding is significant in that it adds a major transitional form to the series describing whale evolution. It also provides new insight by showing that whale evolution could proceed without requiring either teeth or baleen.
Read more at:
Whales lost their teeth before evolving hair-like baleen in their mouths: Newly described fossil whale in museum collections reveals a surprising intermediate step in their evolution
OB
