This strange ancient snake was hiding in a museum for decades

Scientists have now identified those bones as a brand new species called Paradoxophidion richardoweni, and it could help explain where today’s most “advanced” snakes came from.

In 1981, researchers uncovered a set of ancient snake backbones at Hordle Cliff on England’s south coast. For decades, the remains sat in collections. Now they have been recognized as the vertebrae of a previously unknown snake.

A study published in the journal Comptes Rendus Palevol reports that the vertebrae belong to Paradoxophidion richardoweni. The snake lived about 37 million years ago, during a time when England supported a far greater variety of snakes than it does today.

A new fossil snake with clues to modern lineages

Even though scientists only have parts of the spine, the discovery could shed light on the early evolution of the largest group of living snakes. That is because Paradoxophidion appears to be an early branching member of the caenophidians, the group that includes most snake species alive today.

Because it sits so close to the beginning of caenophidian history, the snake shows an unusual blend of traits that are now scattered across different modern snake groups. That patchwork is reflected in its genus name. Paradoxophidion means ‘paradox snake’ in Greek.

The species name honors Sir Richard Owen. He named the first fossil snakes discovered at Hordle Cliff, and he also played a major role in creating what is now the Natural History Museum, where these fossils are housed.

Lead author Dr. Georgios Georgalis, from the Institute of Systematics and Evolution of Animals of the Polish Academy of Sciences in Krakow, says describing a new species from museum collections was ‘a dream come true’.

“It was my childhood dream to be able to visit the Natural History Museum, let alone do research there,” reveals Georgios. “So, when I saw these very weird vertebrae in the collection and knew that they were something new, it was a fantastic feeling.”

“It’s especially exciting to have described an early diverging caenophidian snake, as there’s not that much evidence about how they emerged. Paradoxophidion brings us closer to understanding how this happened.”

Hordle Cliff and England’s warmer Eocene past

Hordle Cliff, near Christchurch on England’s south coast, preserves fossils from the Eocene, a stretch of time from about 56 to 34 million years ago.

Dr. Marc Jones, a curator of fossil reptiles and amphibians who co authored the research, notes that the Eocene was marked by major climate shifts worldwide.

“Around 37 million years ago, England was much warmer than it is now,” Marc explains. “Though the Sun was very slightly dimmer, levels of atmospheric carbon dioxide were much higher.”

“England was also slightly closer to the equator, meaning that it received more heat from the Sun year round.”

Fossil discoveries at Hordle Cliff began roughly 200 years ago. In the early 1800s, Barbara Rawdon-Hastings, the fossil-hunting Marchioness of Hastings, collected skulls of crocodile relatives from the area, including one that Richard Owen later named after her.

Since then, the site has produced fossils of turtles, lizards, and mammals, along with many snake remains, including some that have played an important role in paleontology.

“The fossil snakes found at Hordle Cliff were some of the first to be recognized when Richard Owen studied them in the mid-nineteenth century,” says Georgios. “They include Paleryx, the first named constrictor snake in the fossil record.”

“Smaller snakes from this site, however, haven’t been as well investigated. Paradoxophidion‘s vertebrae are just a few millimetres long, so historically they’ve not had a lot of attention.”

CT scans reveal 31 vertebrae and a digital model

To study the tiny bones in detail, Marc and Georgios used CT scanning. Altogether, they identified 31 vertebrae from different parts of the spine of Paradoxophidion.

“We used these CT scans to make three dimensional models of the fossils,” Marc adds. “These provide a digital record of the specimen which we’ve shared online so that they can be studied by anyone, not just people who can come to the museum and use our microscopes.”

The scans show that the vertebrae vary slightly in shape and size, which is expected because snake spine bones gradually narrow from head to tail. At the same time, shared features across the fossils indicate they came from a single species.

Georgios estimates the snake was under a metre long, but many details remain uncertain. Without a skull, it is hard to tell what it ate. And the vertebrae do not show obvious signs of a highly specialized lifestyle, such as burrowing.

A possible connection to elephant trunk snakes

Even if the fossils do not reveal much about how the snake lived, the vertebrae closely resemble those of acrochordids. These snakes are often called elephant trunk snakes because of their unusually loose, baggy skin.

Today, only a few species of elephant trunk snakes live in southeast Asia and northern Australia. They are also among the earliest branches of the caenophidian family tree, and their fossil record stretches back more than 20 million years.

“As Paradoxophidion is really similar to the acrochordids, it’s possible that this snake could be the oldest known member of this family,” muses Georgios. “If it was, then it could mean that it was an aquatic species, as all Acrochordids are aquatic.”

“On the other hand, it might belong to a completely different group of caenophidians. There’s just not enough evidence at the moment to prove how this snake might have lived, or which family it belongs to.”

Learning more about Paradoxophidion, and about early caenophidian evolution more broadly, will require closer study of additional fossils. Georgios hopes to keep working through the fossil reptile collections soon, where he suspects other undiscovered species may still be waiting.

“I’m planning to study a variety of snake fossils in the collection, including those originally studied by Richard Owen” Georgios adds. “These include the remains of the giant aquatic snake Palaeophis, which were first found in England in the nineteenth century.”

“There are also several bones with differing morphology that haven’t been investigated before that I’m interested in looking at. These might represent new taxa and offer additional clues about snake evolution.”