Four new species of freshwater crabs were recently discovered on Palawan island in the Philippines, according to a report in National Geographic. Hendrik Freitag of the Senckenberg Museum of Zoology in Dresden, Germany, described in a study published in the journal Raffles Bulletin of Zoology. These 1- to 2-inch-wide crabs belong to the genus Insulamon. One species, I. palawanense, is apparently widespread on Palawan, the nation’s longest island out of 7,107 islands. The other three species (I. johannchristiani, I. magnum and I. porculum) can be found only in certain creeks on the island.
What is notable about the four specimens is their bright colorations, which the scientists suspect help the crabs recognize each other. The males of each species are a bright red, while the females and less dominant males retain a purple hue. It is reported that the crabs are nocturnal, feed on plants and small animals, and live their entire lives in and around freshwater.