New Gall Crab Species Discovered

Posted on May 21, 2015

Lithoscaptus semperi

A new species of gall crabs that live in coral have been discovered. The gall crabs can be found in Indonesia and Malaysia. The new species, Lithoscaptus semperi, was discovered by researcher Sancia van der Meij from Naturalis Biodiversity Center in the Netherlands. The holotype of the species was found off Kudat in Malaysian Borneo.

The tiny crabs reach only about 1 centimeter in size and live in small dwellings known as galls in stony corals. The gall crabs settle on coral as larvae and the coral grows around them creating what is called a "gall." Female gall grabs are larger than males and cannot leave their galls. Galls of the new crab species of a male (left) and female (right) are pictured below.

Gall crab dwellings of Lithoscaptus semperi


Sancia van der Meij said in a statement, "When I started working on gall crabs, I had a hard time finding them because of their small size. But once I knew how to recognise their dwellings, I realised they are actually very common on coral reefs."

These gall crabs have so far been found only in Trachyphyllia corals. Gall crabs tend to inhabit a very small number of host species. A research paper by Sancia van der Meij about the new gall crab is published here in the journal ZooKeys.

Photos: BT Reijnen/SET van der Meij