Two New “Vampire” Crab Species Discovered in Indonesia

April 20, 2020 at 4:08 pm

Two stunningly colorful new crab species with spooky yellow eyes found in rivers on the island of Java

Scientists have named and found the origins of two mysterious crabs that have become increasingly popular as pets over the last decade or so.

A purple crab named Geosesarma dennerle and a bright orange crab named Geosesarma hagen originated in two separate river valleys on the Indonesian island of Java.

Geosesarma dennerle CREDIT: Chris Lukhapu, National Geographic

The freshwater crabs’ unusually bright coloring is thought to be an evolutionary result of their amphibious nature, meaning they spend lots of time on the sand, as well as in the water.

On land, “visual communication becomes much more important,” German aquarist Christian Lukhaup told National Geographic

“There’s much more emphasis on color and visual cues rather than chemical cues, as used in the water.”

Geosesarma hagen

Lukhaup became interested in the origins two colorful vampire crabs after seeing them sold around the world as pets.

He scouted out collectors in the aquarium trade to give him clues. “There were a lot of false rumors because people don’t want other collectors to go there,” he said.

He was finally able to track them down in Central Java, where he and his colleague documented their features, named them, and published their findings in the Raffles Bulletin of Zoology.

“Dealers working in Southeast Asia and other parts of the world know what their clients are looking for in terms of colors,” said study co-author Christoph Schubart of Germany’s Regensburg University’s Institute of Zoology.

“They start collecting in areas where scientists may not have made any expeditions so far, and suddenly the market is formed with some animals that no one has ever given a name.”

The scientists suspect there are many more vampire crab species yet to be discovered on the islands of Indonesia. Since freshwater crabs never venture to the ocean and tend to stay put, each of the islands likely have their own unique vampire crab species, Schubart said.

While their main attraction is their wild color schemes, vampire crabs measure less than an inch wide, making them an ideal size for small fish tanks.

Because both of the two species is confined to single watershed, the scientists worry about their popularity leading to their eventually extinction in the wild.

“For the local collectors, it’s their living,” Schubart said. “They just catch what they can get and export it.”

Lukhaup hopes that commercial breeding will help protect wild populations.

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