Tag Archives: scorpion

Fossil Friday: oldest-known scorpion was a pioneer of life on dry land

A set of fossils collected 35 years ago belonged to the oldest-known scorpion species to date, a new study reports.

The fossil (left), its respiratory and circulatory organs (center) and a modern-day scorpion (right).
Image credits Andrew Wendruff et al., (2020), Nature.

The scorpion lived around 437 million years ago and was surprisingly versatile, having the ability to breathe both on land and underwater, the team explains. This fossil helps us make better sense not only of the scorpions’ evolutionary path, but also of how animals transitioned from an aquatic lifestyle to living on dry land.

The first scorpion

“We’re looking at the oldest known scorpion — the oldest known member of the arachnid lineage, which has been one of the most successful land-going creatures in all of Earth history,” said Loren Babcock, an author of the study and a professor of earth sciences at The Ohio State University.

In a new study describing the fossils, researchers named the new species Parioscorpio venator, meaning “parent scorpion hunter”. The fossil was first unearthed in 1985 in Wisconsin at a site that was once a shallow pool on the base of an island cliff face. For 30 years, it was kept in a museum at the University of Wisconsin until Andrew Wendruff, paper co-author and now an adjunct professor at Otterbein University in Westerville, decided to examine it in detail.

This scorpion is about 2.5 centimeters long, similar to many wild scorpions today. Wendruff looked at the fossil under a microscope, taking high-resolution photographs of it from different angles. This process helped highlight bits of the animal’s internal organs, allowing Wendruff to identify its venom appendages and the remains of its respiratory and circulatory systems.

The fossil and interpretative drawing.
Image credits Andrew Wendruff et al., (2020), Nature.

This system is almost identical to those of modern scorpions (which are exclusively land-living) but function more closely to those of horseshoe crabs (which are predominantly aquatic but can breathe on dry land for short periods of time).

The discovery provides new information about how animals transitioned from living in the sea to living entirely on land: The scorpion’s respiratory and circulatory systems are almost identical to those of our modern-day scorpions — which spend their lives exclusively on land — but operate similarly to those of a horseshoe crab, which lives mostly in the water, but which is capable of forays onto land for short periods of time.

The oldest-known scorpion prior to this study had been found in Scotland and dated to about 434 million years ago — it was one of the first animals (that we know of) to live fully on land. This fossil, found in Wisconsin in the Brandon Bridge Formation, is between 1 million and 3 million years older, the authors explain. They were likely alive between 436.5 and 437.5 million years ago, during the late Paleozoic era.

“What is of even greater significance is that we’ve identified a mechanism by which animals made that critical transition from a marine habitat to a terrestrial habitat. It provides a model for other kinds of animals that have made that transition including, potentially, vertebrate animals. It’s a groundbreaking discovery.”

The paper “A Silurian ancestral scorpion with fossilised internal anatomy illustrating a pathway to arachnid terrestrialisation” has been published in the journal Scientific Reports.

Scorpion venom protein might be used to ferry drugs to the brain

Researchers have found a way to take advantage of one of venom’s most dangerous properties: its ability to reach the brain.

Image via Wikipedia.

The brain is the most complex human organ, and like any complex mechanism, it’s vulnerable to external interference. That’s why it’s hidden in our sturdy skulls, surrounded by cerebrospinal fluid, and locked tight by the blood-brain barrier (BBB). The blood-brain barrier is a highly selective semipermeable border that ensures no unwanted pathogens reach the brain.

However, all this protection comes at a cost: it’s really hard to for doctors to deliver necessary drugs to the brain, and sometimes, a drug has to be administered directly into the cerebrospinal fluid.

“About 98% of drugs that could have therapeutic applications cannot be used because they cannot cross this barrier,” explains Ernest Giralt one of the authors of the new study, and lab leader at the Institute for Research in Biomedicine Barcelona.

Giralt and colleagues may have found a workaround that issue, employing the usage of an unexpected substance: venom.

The venom of the Giant Yellow Israeli scorpion (Leiurus quinquestriatus), a species native to desert habitats ranging from North Africa through to the Middle East, could hold the key. The venom holds a small protein (a peptide) derived from chlorotoxin that has the ability to penetrate the blood-brain barrier.

“Our goal is to enable drugs to enter the brain and to do this we bind them to peptides specifically designed to cross the BBB. The conjugation of these drugs to the shuttles would improve their efficacy,” says Meritxell Teixidó, co-leader of the research.

Essentially, the venom could serve as a shuttle for drugs — which is not entirely a new idea. In previous studies, scientists took inspiration from a peptide found in bee venom (named apamin), making a few minor chemical modifications to ensure that it can pass the BBB. However, chlorotoxin, which is found in the venom of the scorpion, already has this ability — it’s one of the reasons why the scorpion’s venom is so dangerous. In other words, they took one of the threats of venom and found a way to use it as an advantage.

“Thousands of venoms that hold millions of peptides with the shuttle potential have been described. We chose chlorotoxin because it has already been reported that it acts like a toxin in the brain,” explains Teixidó.

So far, preliminary results are highly encouraging. Although this still needs to be investigated and thoroughly confirmed, it’s quite promising.

“Our results reveal animal venoms as an outstanding source of new families of BBB-shuttles,” researchers conclude.

The study “From venoms to BBB-shuttles. MiniCTX3: a molecular vector derived from scorpion venom” has been published in Chemical Communications.

A component from scorpion and honeybee venom stops cancer growth

Scorpion toxins may soon be useful as anticancer drugs. Credit: Courtesy of Dipanjan Pan

The difference between a poison and a cure is the dosage – and this could be very well said about this approach. Bio-engineers report that peptides in some venoms bind to cancer cells and block tumor growth and spread and could be effectively used to fight cancer – the only problem is they might also harm healthy cells.

Bioengineer Dipanjan Pan and coworkers at the University of Illinois, Urbana-Champaign, are now using polymeric nanoparticles to deliver venom toxin directly to cancer cells. The problem is limiting the effect it has to the cancer cells, and avoiding any damage to healthy cells. The researchers inserted a derivative of TsAP-1, a toxin peptide from scorpion venom, into specific spherical nanoparticles, constructing what they call NanoVenim. When they tested it on cancerous tissue in the lab, NanoVenim was 10 times more effective at killing the cancerous cells and spreading their growth than the toxin alone.

They researched a similar procedure with a nanoparticle-encapsulated version of melittin (a toxin from honeybee venom), and the results were even more promising. The toxin had potency against cancer cells, but on the upside, it didn’t do any damage at all to healthy cells.

“We have known for some time that venom toxins have anticancer potential, if only we could deliver them safely and selectively to tumors,” said David Oupicky, codirector of the Center for Drug Delivery & Nanomedicine at the University of Nebraska Medical Center.

However, the trick here is nanotechnology; even a simple nanotechnological delivery method can work wonders (such as increasing the efficiency 10 times). Pan’s idea with scorpion venom injected through nanotechnology  “is new, and the method of incorporation into nanoparticles is fairly new as well,” he added. But it’s perhaps the honeybee venom which shows the most promise:

 “[That it] works against cancer cells but appears not to damage erythrocytes is an important step toward practical application. It will be very interesting to see how the particles behave in vivo.”

Now, having successfully tested the idea on lab tissue, the next step is to conduct animal tests. Pan’s team founded a start-up, VitruVian Biotech which will conduct testings on rats and pigs. However, with so promising results, he believes that they could start human clinical trials in three to five years.

350-million-year-old former inhabitant of Gondwana found

A 350 million year old fossilized scorpion has become the world’s oldest known land animal to have ever walked the supercontinent Gondwana.

Ancient history

laurasia gondwana

It’s 350 million years ago – take a moment to ponder that. Take a long human lifespan of 100 years, and multiply it by 100, and again by 100 – now you have a million years. Multiply it again by 350, and you get to the life of this now fossilized scorpion! It blows my mind just to think about that; it was so long ago, that the face of the Earth looked nothing like it does now.

There were only two major continents back then, called Laurasia and Gondwana, separated by the Tethys sea. Gondwana included most of the landmasses in today’s Southern Hemisphere, including Antarctica, South America, Africa, Madagascar and the Australian continent, as well as the Arabian Peninsula and the Indian subcontinent, which are now a part of the Northern hemisphere.

Paleozoic Era

We’re in a period called Carboniferous – when amphibians were dominant land vertebrates and were almost starting to evolve into reptiles, arthropods are extremely common, and vast swaths of forest cover almost every inch of land; these forests will lie down and eventually become coal – thus giving the name of the period (Carboniferous = coal bearing).

The oldest land walking Gondwanese

scorpion gondwana

Ok, Gondwanese isn’t a real word, I just made it up. But this new species, Gondwanascorpio emzantsiensis is the oldest we know that walked on Gondwana. Its discovery brings some tantalizing clues about the development of life before Earth’s continents broke apart to form the continents as we see them today.

“There has been no evidence that Gondwana was inhabited by land living invertebrate animals at that time,” said Robert Gess who is based at the Evolutionary Studies Institute at Wits University.

Gess uncovered the scorpion fragments—with a pincer and a sting clearly showing in the rock in South Africa, near the Eastern Cape. The implications this finding has are quite significant.

“For the first time we know for certain that not just scorpions, but whatever they were preying on were already present in the Devonian,” added Gess.

“We now know that by the end the Devonian period Gondwana also, like Laurasia, had a complex terrestrial ecosystem, comprising invertebrates and plants which had all the elements to sustain terrestrial vertebrate life that emerged around this time or slightly later,” said Gess.

scorpion 2

The first real land vertebrates, from which ultimately even humans evolved appeared some 350 million years ago.

Journal reference: The earliest record of terrestrial animals in Gondwana: A scorpion from the Famennian (Late Devonian) Witpoort Formation of South Africa.