Researchers have found in the Philippines four totally new species of freshwater crabs belonging to the genus Insulamon, each of which is notable for the bright purple-violet color shell and limbs. Detailed description of identified species is presented in an article published in The Raffles Bulletin of Zoology.
The animals in the course of the expedition discovered a German zoologist Hendrik Freitag, Palawan, and a number of adjacent small islands. A little earlier in this area was open only one species of the genus - Insulamon unicorn, which have now been added four new species with a distinctive color, an unusual structure of the shell, limbs, and many other features of the anatomical structure.
Dimensions of new arthropod carapace relatively small - the largest of the four species, Insulamon magnum, they reach no more than four or five centimeters. The habitat of animals - fresh water bodies and streams, where their main food is vegetation, various fruits and even small animals. These crabs are nocturnal and hide during the day.
Zoologist Hendrik Freitag notes that the crabs have the ability to distinguish colors, and probably their color bright color has a special meaning in the mating season. So, in a bright purple colored shells only immature females and young males. Males on as the growing, changing their purple to red.
Known fact that the majority of arthropods, including crabs, except for shades of colors are able to distinguish between more and polarization of light. There are species that use it for communication within a species. For example, cuttlefish having greater sensitivity to polarization are particularly coloring, which can be seen only under polarized light, and it is noticeable only representatives of their species. However, the researchers did not consider the possibility of this type of communication in crabs.
According to data recently published report in the world opens in the present, about 18,000 new species a year, and many of them are not in the expedition, and in the archives of many biological museums. Scientists around the world are turning to intensify the appeal procedure descriptions of new species due to the increasing reduction of areas of different habitats of wild animals and plants.