Monday , May 17 2021

Fossil named after curator Burke tells whale from story of evolution – GeekWire



Carlos Mauricio Pedroso
Carlos Mauricio Pedroso, a researcher at the National Museum of Natural History, shows that the 33 million-year-old acidic fossil is newly-classified by the name Maiabalaena nesbittae. (Smithsonian Photography)

A 33 million-year-old kit, when today's Oregon was part of the ocean floor, is a new name by curator at the Burk Seattle Museum of Natural History and Culture.

Elizabeth Nesbit's whale is not a typical cetacean. The analysis of the fossil, published in the November 29 biology edition, suggests that Maiabalaena nesbittae bridge the gap between species of whales that have teeth and species that have a different mouth – a feeding mechanism known as Balin.

"For the first time now, we can determine the origin of filtering, which is one of the major innovations in the whale's history," says co-author Nicholas Pyenson, curator of the National Museum of Natural History of Fossil Marine Mammals and a companion curator at the Burk Museum, according to a press release.

M. nesbittae fossil was discovered in the 1970s and has since been widely studied. However, the rock matrix and the material around the fossil passed through many of its features, a frustrating formal classification. Then Carlos Mauricio Pedroso, a researcher at the National Museum of Natural History, gave him thorough cleansing of the fossil and examined him with the latest X-ray scanning technology.

A closer look at the scans showed that the jaw of M. nesbittae had no teeth. That is not surprising in itself: A whale, probably 15 meters long, lived at a time when some species of whales made an evolutionary passage from using teeth to use balin.

Baleen are rows of flexible, clean pieces that putty species such as humpbacks and blue whales used to filter tiny prey from giant gulps on the ocean water. Feeding technology allows white whales to consume tons of food every day without biting or chewing.

What makes M. nesbittae special is that the upper jaw is thin and narrow, which seems to be unsuitable for supporting the ball structure.

"A live ballet whale has a large, wide roof in the mouth, and it is also thickened to create places for attachment to the bales," says Pededo, who is the current author of the current biology study. "Maiabalaena no. We can tell you fairly that these fossil species had no teeth, and it's more likely than not having been baleen."

It would support the hypothesis that some kite species have evolved to exploit a feeding strategy that did not require either teeth or baleen.

Pededo and his colleagues say the muscle supplements of the M. nesbittae bones indicate that they have strong cheeks and language. They suggest that the whale could suck large amounts of water into the mouth, taking small fish and squid in the process … without teeth. (The modern narwhal, which has only two toothed teeth, uses a similar strategy.)

In this scenario, the loss of teeth sets the stage for the appearance of filter-billet structures millions of years later. The main factor behind the divergence in feed strategies was probably a dramatic cooling of ocean waters during the transition from Eocene to the oligocene era, about 34 million years ago.

It seems that the status of M. nesbittae as a transitional species is reflected in the name of the genus that Pedro and his colleagues chose for their formal description of the fossil.

"The name is Maiabalaena, which combines" Maia ", which means mother, and" balloon ", which means whale," said Pededo. "She is named for her position close to the base of a family of peanut whales."

Pededo said that the name of the species, nonsense, distinguishes Nesbit "for her life in the contribution to the paleontology of the Pacific Northwest and her mentoring and collegiality in the Burk Museum."

Elizabeth Nesbit
Elizabeth Nesbit is the curator of paleontology and micro-pheletology of invertebrates at the Burk Museum. (University of Washington Photography)

Fainting explores fossils across western North America, with particular emphasis on marine fossils. Her research also focuses on the microbiota of today's Puget Sound, and how small creatures known as foraminifera serve as key indicators for the health of Puget Sound. (Spoiler warning: the indicators do not look good.)

Apart from her research, Nesbit plays a role in the public as curator of the Burke Museum of Paleontology and Micro Palaeontology. The museum says it has compiled items on topics ranging from the seismic history of the Pacific Northwest to imaginative representations of ancient fossils as they seemed in life.

Pedrodo is familiar with the work of Nesibi, partly because his own research has made extensive use of fossils from the state of Washington and Oregon – including, of course, the fossil that now carries her name.

In addition to Pedro and Piencon, the authors of the document Current Biology, entitled "Loss of teeth before the origin of Balin in whales," include Christopher Marshall and Mark Uechen.


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