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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 the New Mexico Museum of Natural History and Science curator and paleontologist Spencer Lucas.
Lucas, Museum Research Associate Allan Lerner and United Kingdom paleontologist Simon Braddy revealed their discovery in a recently published article in the scientific journal “Historical Biology.”
Lucas has been collecting and studying fossils in New Mexico for more than 40 years, and even he was taken aback by the find.
“The reason this is important … is we never saw anything like this before,” Lucas said, in a Monday phone interview. “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 museum’s attention. The fossil is mainly the back half of the animal – mostly the tail – or telson, the tail spike.
“A lot of people find fossils and bring them to our attention; it’s just that not many discoveries are as important as this one,” Lucas said.
“These types of sea scorpions are pretty rare as fossils so there are very few of them … that have ever been found in North America,” Lucas said. “It’s a very unusual, rare kind of sea scorpion.”
The new species has been named Hibbertopterus lamsdelli, named after West Virginia University paleontologist James Lamsdell, an expert on fossilized sea scorpions.
“Having a species named after me is a huge surprise – it is one of the greatest honors that a researcher can receive,” Lamsdell said in an email, “and it’s certainly not something I ever expected to happen.”
The museum noted in a news release that “Hibbertopterus lamsdelli belongs to a group of bizarre sea scorpions, the hibbertopterids, that reached lengths of over six feet.” The New Mexico discovery is only the fourth fossil discovered of an American hibbertopterid.
“I think it bodes well for future discoveries. So, it’s just a surprising discovery to find this strange, big animal,” Lucas said.
Sea scorpions existed at least 100 million years before this fossil.
Based on other fossil finds, “the general thinking is that these sea scorpions, by the time you get to 300 million (years), they migrated into fresh water,” Lucas said.
Sea scorpions became extinct at the end of the Permian Period, about 252 million years ago.
This one was not in a “real freshwater setting” and was found in rocks deposited right next to what would have been the sea, which raises the question of whether it was living where it was found or washed in from a river, he said.
“Did these animals really all migrate into a freshwater habitat or were some of them still living in the sea and we are now only discovering (them)?” Lucas asked. “There’s no way to really know.”
Various species of sea scorpions had different-size claws, and may or may not have been eating fish, depending on when they existed.
This animal belongs to groups that didn’t have big claws, probably weren’t eating fish and were “sweep feeders.”
“These things have a lot of legs and it’s thought that they used their legs to sweep the bottom of whatever water body they were in.”
This group of sea scorpions were large and known for “having an unusual life habit, living a bit like giant aquatic Roombas that trundled across the floor of lakes and rivers, scooping soft-bodied prey out of the mud to eat,” Lamsdell said. They were “one of only two groups of sea scorpion 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 Fishes.
Fish-eater or not, Lucas believes that, 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 around and you encountered 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 get out of the water.”
According to the website, the Conversation, sea scorpions are among the largest marine predators in the fossil records.
“Some of these giants were effectively in the same place in their food web as the modern great white shark,” the website said. “These likely agile swimmers would have used their large front limbs, armed with claws, to grab their prey, which they would then crush between the teeth-like structures on their legs.”
The sea scorpion fossil is part of the collection at the Museum of Natural History and Science, which is the Southwest’s largest repository for fossils; it will go on view at the museum in the coming months.