Scientists Discover New Species, Genus of Freshwater Crabs Being Sold in Chinese Pet Market

An international team of researchers has discovered that the colorful freshwater crabs popular in ornamental fish markets in China actually belongs to a new species and genus of freshwater crab.

According to a press release, three researchers from the University of South Wales in Australia, The Australian Museum, Sun Yat-sen University in China and National Ching Hsing University in Taiwan have taken an interest in the freshwater crabs being sold in the pet market. The researchers noticed that the freshwater crabs have an unusually structured male gonopod, which in crustaceans is a swimming appendage modified to serve as a reproductive organ.

Due to crab's peculiarities, lead author Chao Huang persuaded a local fish dealer to take them to the collection site located in northern Guangdong, southern China. The researchers surveyed the collection site and collected some sample of the crabs.

DNA testing and molecular analyses have confirmed that the freshwater crabs being sold as pet in China belongs to a new species and genus.

The new species and new genus of freshwater crabs found in China is described in a paper published in the journal ZooKeys. Due to its apparent preference to the pools of limestone hillstreams, the new freshwater crab was named Yuebeipotamon calciatile, in which calciatile means living on limestone.

The new genus possesses a distinctive combination of carapace, ambulatory leg, male thoracic sternal, male abdominal and gonopodal characters that distinguish it from these and other genera.

Yuebeipotamon calciatile is characterized by its slender legs, which is believed to be developed to adapt to its habitat. Their slender legs make it easy for the crabs to climb and move around in the short-lived limestone hillstream.

Other distinguishing features of the new freshwater crabs include the color of its carapace, claws and legs. Its carapace appears to be maroon to dark brown, while the claws and legs are reddish to purple. Furthermore, the adult Yuebeipotamon calciatile are much more vivid compared to the juveniles.