Last week, scientists from Germany's Senckenberg Museum of Zoology announced the discovery of four new species of freshwater crabs in the biologically diverse island province of Palawanin the Philippines. Confined to a small inland area within the lowland-forest ecosystems of the island, the tiny crustaceans feature bright purple or red shells and red-tipped claws.

Hendril Freitag, the head zoologist for the museum believes that since crabs can discriminate colors, the different hues could possibly signal their power - Red for the larger more dominant male and purple, for the smaller females and young adult males.

Regardless of color the carapaces or exoskeletons of all four species are strong and hard, protecting them against river rocks. This is important for their survival, given the unlike other freshwater crabs they do not migrate to the ocean or dry land, but spend their entire lives burrowed under boulders and roots in streams, feeding off dead plants, fruits and small animals. The crabs' exterior also appears swollen because of their large gill chamber that allows them to breath and stay longer on land. Their inability to be able to migrate to the ocean and survive in saltwater, makes the species highly susceptible to extinction, even if their environment changes slightly.

All four new species which have been categorized under the Insulamon Genus are quite tiny - The biggest, called Insulamon Magnum is 53 millimeters by 41.8 millimeters while the smallest, Insulamon Porculum, measures just 33.1 by 25.1 millimeters.

US-based Conservation International, lists the Philippines as one of 17 countries that harbor most of Earth's plant and animal life. Unfortunately, like these purple crabs, a lot of it is vulnerable because the forests are being cleared to make room for farming, mining and home building, effectively reducing if not completely destroying, the habitats of many species.

Resources: news.discovery.com, nationalgeographic.com