Spiky ‘pirate’ creatures found on tropical island. They’re a ‘remarkable’ new species

Researchers recently discovered a host of “fascinating” arachnids living on St. Helena, a British territory in the south Atlantic Ocean.

Long thought to be an common species that had been introduced from Europe, researchers took a closer look at collected specimens. It turned out, they belong to two previously unknown species of spiders, according to a study published on Feb. 2 in the European Journal of Taxonomy.

Specimens of both species were collected from the island’s cloud forests and subjected to DNA analysis, researchers said.

Upon analysis, they were both grouped into the genus Ero, which contains 40 known species, a half dozen of which are native to the tropics of Africa.

Members of the genus are known as pirate spiders, meaning they engage in cannibalism.

They typically “hunt by picking at the strands on their prey’s web to simulate the movements of either a trapped insect or a potential mate,” according to an Australian arachnid guide. “When their prey comes to investigate, they are instead captured and eaten.”

The first species, named Ero lizae, measures around 4 millimeters long and is colored brown with black and whitish blotches.

It is considered “remarkable” because it is distinguished from all others in the genus by a pair of “large spike-like protuberances” on the posterior of its body, researchers said.

Its name lizae was chosen to pay homage to Liza Fowler, a conservationist who has worked on the island for over a decade.

The second species, named Ero natashae, is slightly smaller in size, measuring around 3 millimeters long, researchers said.

It is also brownish in color with a series of dark and light blotches.

Though it appears similar to lizae, it is “easily distinguished by the absence of large spike-like tubercles…” researchers said.

It was also named after a local conservationist, Natasha Stevens, who spent years analyzing invertebrates on the island.

The discovery of the two arachnids reinforces that the island serves as an biodiversity hotspot in the Atlantic Ocean, researchers said.

Because of its isolation, St. Helena is home to numerous species that are found nowhere else in the world, according to the island’s tourism department.

“St. Helena holds roughly 30% of all endemic species to be found in the U.K. and the British Overseas Territories,” according to the department.

Further studies are required to better understand the life history of the two spider species, researchers concluded.