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Quarry discovery defies previous beliefs on ancient species

 

A team of researchers have shared the secrets of a 93-million-year-old fossil, uncovered just nine years ago in a Mexican quarry.

The shark species has been named Aquilolamna milarcae, which relates to species of long-winged sharks (similar to manta-rays). The astonishing discovery, with its 1.9 metre wingspan, reveals that manta-like species were around 30 million years earlier than previously thought.

When the fossil was found near Vallecillo, in northeastern Mexico, quarry workers passed the specimen over to a local researcher who donated it to a public museum. From there the most recent report on the specimen was not kicked off until 2017, when a team of geologists, palaeontologists and shark specialists formed to learn more about the animal and how it came to be inside a limestone slab of inland Mexico.

Geoscientist Romain Vullo from the University of Rennes told Quarry just how the fossil came to be.

“After the death of the animal about 93 million years ago, the carcass sunk and was deposited on the muddy sea floor,” Vullo said.

“Because of the absence of scavengers and strong currents, the skeleton was not disarticulated and could be preserved in the sediment that became over time a laminated limestone layer.”

Vullo said that the quality and nature of the discovery was in its own class of rarity.

“Even if fossils are regularly unearthed in many quarries or natural outcrops, such discoveries (here a complete fossil shark with an outstanding morphology) remain exceptional,” Vullo said.

The fossil will be exhibited in the Museo La Milarca near Monterrey, 120km south of where it was discovered.

Vullo said his team can only hope further discoveries can be made to unearth more about the ancient animal.

“We hope that a second specimen of Aquilolamna milarcae will be discovered in the future and that we will be able to get further information on the anatomy (eg tooth morphology) and lifestyle of this amazing species,” Vullo said.