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Giant sea scorpion fossil discovered near Albuquerque

Reconstruction of Hibbertopterus, the giant sea scorpion. (Ceri Thomas/Nix Illustration)

Copyright © 2022 Albuquerque Journal

SANTA FE — Scientists have discovered the fossil — never found in New Mexico before — of a new species of giant sea scorpion in the Manzano Mountains.

The 4-foot-long fossilized predator was found in 305-million-year-old rocks last year and brought to the attention of New Mexico Museum of Natural History and Science curator and paleontologist Spencer Lucas .

Lucas, museum research associate Allan Lerner and British paleontologist Simon Braddy revealed their discovery in an article recently published in the scientific journal “Historical Biology”.

Lucas has been collecting and studying fossils in New Mexico for over 40 years, and even he was surprised by the find.

“The reason it’s important…is that we’ve never seen anything like this before,” Lucas said in a phone interview Monday. “This kind of animal has never been found here.”

A citizen, whom Lucas did not wish to identify, made the discovery last year and brought it to the attention of the museum. The fossil is mainly the back half of the animal – mainly the tail – or telson, the tip of the tail.

“A lot of people find fossils and bring them to our attention; it’s just that few discoveries are as significant as this one,” Lucas said.

“These types of sea scorpions are quite rare in fossil form, so there are very few…that have ever been found in North America,” Lucas said. “It’s a very unusual and rare type of sea scorpion.”

The new species has been named Hibbertopterus lamsdelli, after West Virginia University paleontologist James Lamsdell, an expert on fossilized sea scorpions.

“Having a species named after me is a huge surprise – it’s one of the highest honors a researcher can receive,” Lamsdell said in an email, “and it’s certainly not something I would have imagined.”

The museum noted in a press release that “Hibbertopterus lamsdelli belongs to a group of bizarre marine scorpions, the hibbertopterids, which reached lengths of over six feet.” The New Mexico find is only the fourth discovered fossil of an American hibbertopterid.

“I think this bodes well for future discoveries. So it’s just a surprising discovery to find this strange big animal,” Lucas said.

The giant sea scorpion fossil found in the Manzano Mountains. The fossil is mainly the telson, or tail, of the animal. Sea scorpions became extinct about 252 million years ago. (Courtesy of Spencer Lucas)

Sea scorpions existed at least 100 million years before this fossil.

Based on other fossil finds, “the general idea is that these sea scorpions, by the time you get to 300 million (years old), they’ve migrated into fresh water,” Lucas said.

Sea scorpions became extinct at the end of the Permian period, around 252 million years ago.

This one was not in a “true freshwater environment” and was found in rocks deposited right next to what would have been the sea, raising the question of whether it lived where it did. was found or if it was swept away by a river, he said.

“Did these animals really all migrate to a freshwater habitat or did some of them still live in the sea and we’re just discovering them now?” Lucas asked. “There’s no way to really know.”

Various species of sea scorpions had claws of different sizes and ate fish or not, depending on when they existed.

This animal belongs to groups that did not have large claws, probably did not eat fish and fed by sweeping.

“These things have lots of legs and it is believed that they used their legs to sweep the bottom of any body of water they were in.”

This group of sea scorpions were large and known to “have an unusual life habit, living much like giant aquatic Roombas that rolled around on the floors of lakes and rivers, picking up soft-bodied prey from the mud to eat. “, said Lamsdell. They were “one of only two groups of sea scorpions to survive the mass extinction at the end of the Devonian (period),” he said. The Devonian period was part of the Paleozoic era known as the Age of Pisces.

Fish eater or not, Lucas thinks if you were around back then, you might not have wanted to swim with the scorpions.

“If you were in the water 300 million years ago, swimming and encountering this animal, it probably wouldn’t have been a danger to you, but, personally, if I encountered a scorpion four feet long swimming in the water with me I think I would come out of the water.

According to The Conversation website, sea scorpions are among the largest marine predators in the fossil record.

“Some of these giants were indeed in the same place in their food web as the modern great white shark,” the website says. “These probably agile swimmers would have used their large forelimbs, armed with claws, to grab their prey, which they would then crush between the tooth-like structures on their legs.”

The sea scorpion fossil is part of the collection of the Museum of Natural History and Science, which is the largest repository of fossils in the Southwest; it will be presented at the museum in the coming months.