As I mentioned previously, the antarctic is home to a startling, and poorly surveyed, preponderance of marine life. Now, the British Antarctic Survey has released some excellent photographs of some of these animals. Here are the arthropod highlights (click the photos to embiggen):
Serolid sp. – Wait, yesterday didn’t I say that trilobites are extinct? Well, that is still true. This animal is actually an isopod crustacean, related to terrestrial pill bugs. The flattened body shape of this animal is an adaptation that makes it easier to burrow into sediment.
Antarcturus sp. – Despite the apparent morphological disparity, this is also a member of the isopod order. This animal is a member of the Antarcturidae family. Unlike Serolids, which are bottom-dwelling scavengers, these isopods live on the branches of coral and sponges. They reach their long frontal appendages out in the water column to catch planktonic prey.
These two isopods nicely demonstrate the tremendous amount of morphological diversity that similar animals can evolve in order to best suit their lifestyle. Furthermore, Serolid sp. is a great example of convergent evolution between isopods and trilobites. These two arthropod groups are unrelated, yet species within them have evolved a similar body shape in order to best suit their shared bottom-dwelling lifestyles.