New purple crab species found in Philippines

The tiny crustaceans burrow under boulders and roots in streams, feeding on dead plants, fruits, carrion and small animals in the water at night, said Hendrik Freitag of Germany’s Senckenberg Museum of Zoology.
Found only in small, lowland-forest ecosystems in the Palawan island group, most have purple shells, with claws and legs tipped red.
“It is known that crabs can discriminate colours. Therefore, it seems likely that the colouration has a signal function mating,” Freitag told AFP by email on Saturday.
“This could explain why large males of various Insulamon species are more reddish compared to the generally violet females and immature males.”
Scientists began extensive investigations of similar freshwater crabs in the area in the late 1980s, when one new species was found the Insulamon unicorn, Freitag said.
More field work led Freitag to conclude there were four other unique species.
“Based on available new material, a total of five species are recognised… four of which are new to science,” Freitag wrote in the latest edition of the National University of Singapore’s Raffles Bulletin of Zoology.