Ancient whale species provides link in evolution question

Posted at 12:17 PM, Nov 30, 2018
and last updated 2018-11-30 14:12:20-05

Scientists from Texas A&M found key information about the evolution of baleen from a newly named fossil whale.

The Maiabalaena nesbittae gave clues to experts about how the filter-feeding system progressed over time in mysticete whales.

It has been known that the ancestors of mysticete whales had teeth, but it remained a mystery how the transition from eating with teeth to filter feeding with baleen took place. There had been several theories, but the new discovery points scientists in a new direction.

Researchers believe that Maiabalaena nesbittae did not have teeth or baleen.

Whales are classified into toothed whales that hunt their prey with their teeth and baleen whales that strain the water to capture small prey. Baleen is made of keratin, the same material as fingernails. It has hair-like fringes on one side, and when hundreds of plates are stacked they form the filter.

The new whale species shows that early mysticetes experienced tooth loss prior to evolving baleen. The question remained, how did it eat? The answer can be seen in living whales that have functional teeth and use suction to feed. The suction is an ancestral feeding strategy for most marine vertebrates. Maiabalaena has many anatomical aspects that support a suction feeding strategy.

The new whale species was described by Carlos Peredo, a doctoral student at George Mason University, and  co-authored with Dr. Christopher Marshall, a professor in the Department of Marine Biology at Texas A&M University at Galveston, Dr. Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian National Museum of Natural History Department of Paleobiology, and Dr. Mark Uhen of George Mason University.

Peredo and Marshall discussed the whale’s unique bone structures to support their findings.

“So it turned out to be a natural collaboration between Nick, Carlos, Mark and myself,” said Marshall. “It just developed that semester I was there. I’ve been going back ever since and now am a research associate with the Smithsonian.”

“This discovery is a big deal for us,” said Marshall. “It’s filled an important gap in understanding the evolution of baleen and filter feeding. Understanding the pattern of how baleen evolved in mysticetes is as important as other major evolutionary transformations such as scales to feathers in birds. Such anatomical transformations fundamentally altered the natural history of baleen whales.”

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