Sea spider sucks live prey

Strange creatures like spiders live on the ocean floor and use taps to suck fluid from prey that are confusing to scientists.

Sea spider
(Photo: ABC Online)

These sea spiders, some blind, are challenging the scientific classification.

The marine biologist Claudia Arango at the Australian Museum in Sydney agrees that they belong to the arthropod family, but which group is still unknown.

For more than 100 years, scientists have not understood what sort of sea spider to put . They crawl along the sea floor, sometimes below 6,000-7,000 m, they live in the dark and eat sponges and sea cucumbers.

These creatures consist of many pieces and have an exoskeleton that makes them arthropods, with their families with crustaceans, insects, polyps and spiders.

But they also have a strange set of characteristics, and a unique eating mechanism."They have a nozzle like a straw that they press on the prey and suck out the fluid , " Arango said.

These characteristics make it difficult to put them in any known group of arthropods.

Arango has studied the diversity and evolution of sea spiders. She used DNA and morphological technology to create a family tree, based on 60 sea spiders worldwide.

Some scientists believe that sea spiders are a group of primitive creatures that appear, at the base of the arthropod family tree. But Arango's search results supported another theory: that they have them closer to the arthropod group including spiders and scorpions.

Arango said the most exotic sea spiders live in Antarctica. They are richer, more crowded, bigger and more bizarre than other sea spiders.

MT