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¿Cómo consiguieron los elefantes y las morsas sus colmillos? Es una larga historia.

BLOG # 77 Nov 2, 2021 at 5:02:52 PM

How Did Elephants and Walruses Get Their Tusks? It’s a Long Story.

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-A new study reveals how some mammals evolved nature’s most impressive chompers (which are not always used for chomping).

Elephants have them. Pigs have them. Narwhals and water deer have them. Tusks are among the most dramatic examples of mammal dentition: ever-growing, projecting teeth used for fighting, foraging, even flirting.

So why, across the broad sweep of geologic history, do such useful teeth only appear among mammals and no other surviving groups of animals? According to a study published Wednesday in the journal Proceedings of the Royal Society B, it takes two key adaptations to teeth to make a tusk — and the evolutionary pathway first appeared millions of years before the first true mammals.

Around 255 million years ago, a family of mammal relatives called dicynodonts — tusked, turtle-beaked herbivores ranging in stature from gopher-size burrowers to six-ton behemoths — wandered the forests of the supercontinent Pangea. A few lineages survived the devastating Permian extinction period, during which more than 90 percent of Earth’s species died out, before being replaced by herbivorous dinosaurs.

“They were really successful animals,” said Megan Whitney, a paleontologist at Harvard University and the lead author of the study. “They’re so abundant in South Africa that in some of these sites, you just get really sick of seeing them. You’ll look out over a field and there’ll just be skulls of these animals everywhere.”

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My 2 cents opinion:
No doubt that having these external bones was of important evolutionary usefulness to creatures with no hands.

Sin duda, tener estos huesos externos fue de importante utilidad evolutiva para las criaturas sin manos.


*Read More https://www.nytimes.com/2021/10/28/science/elephant-walrus-tusks-evolution.html?smid=em-share