A giant species of sea scorpion found in New Mexico

Scientists have discovered a giant species of ancient sea scorpion in New Mexico that lived between 307 and 303 million years ago.

Hibbertopterus lamsdelli was more than a meter long and probably lived in a sea-influenced estuary fed by a river delta, according to a new study published in the journal Historical Biology.

It belonged to an extinct group of aquatic arthropod invertebrates that probably fed on small crustaceans, invertebrate larvae and gastropod eggs, said scientists, including those from the New Mexico Museum of Natural History in the US.

Such hibertopterid sea scorpions are extremely rare in the world, and this newly discovered fossil is only the fourth – and “the most reliable” – specimen reported from the US.

Hibbertopterus lamsdelli important because these fossils are so rare,” study co-author Simon Braddy told Sci.News.

“It’s also the most reliable American hybbertopterid – this group of giant brush-feeding eurypterids (sea scorpions),” Dr Braddy said.

“It is unlikely that they fed on large prey. Instead, they used their anterior appendages to probe the substrate for shallow, shallow animals such as small crustaceans and worms,” the researchers wrote in the study.

Although these sea scorpions were generally rare as fossils, researchers said they are locally abundant in American and European sedimentary rock deposits dating to this time period.

The fossils studied in the research were obtained from the Atrasado Formation at the Kinney Quarry, Bernalillo County in central New Mexico.

Researchers say the fossil was collected from the top of Kinney Quarry bed 3, a 15-16 cm thick, mostly gold-colored, laminated bituminous limestone to a calcareous siltstone known as the “fish bed.”

They said that the fossil is preserved as a layer of carbonated cuticle and consists of component and incomplete.

The uncovered fossil probably represents the molting of a sea scorpion, a process that involves the shedding of its exoskeleton.

The fossil was carried a short distance and had partially slipped out, a sign that the skeleton had not completely dissociated from the body.

“It was just over 1m long and like Hibbertopterus scouleri, from Scotland, but with a wider body segment before its dorsal tail, which itself was shorter, with more parallel keels on the underside.” Dr. Braddy said, according to Sci.News.

“These acted like sled rails to reduce body drag when it pulled itself out of the water during seasonal nuptial (mating) walks,” he explained.

Unusual spines found on the legs of sea scorpions probably acted to help spread the load during their journey.

“Hibbertopterus it had walking legs with spinose extensions at the base (Weighted) to spread their load, and the ventral keels on their telson [last abdomen segment] function like sled rails to reduce body drag,” scientists wrote in the study.

Leave a comment