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Ancient Shrimp-Like Creature Has Oldest Known Circulatory System
sciencehabit (1205606) writes "A 520-million-year-old shrimp-like creature known as Fuxianhuia protensa has the oldest known cardiovascular system, researchers report. It was both modern and unsophisticated. A simple, tubelike heart was buried in the creature's belly — or thorax — and shot single blood vessels into the 20 or so segments of its primitive body. In contrast, x-ray scans of the specimen revealed profoundly intricate channels in the head and neck. The brain was well supplied with looping blood vessels, which extended branches into the arthropod's alienlike eyestalks and antennae and rivaled the complexity of today's crustaceans. From this Gordian architecture, the researchers can now speculate about the critter's lifestyle. Its brain required abundant oxygen, so it presumably did a fair amount of thinking."
...have been posted by nerval's lobster?
That's why it's called shrimplike. It's definitely no shrimp, it's not even a crustacea, it's an animal that was close to the common ancestor of insects, crustaceans and spiders.
No, they don't. Sponges, medusae and polyps don't have a cardiovascular system for instance.
Replying to myself: Most insects don't transport much of their oxygene via the blood anyway, they have tracheae, which basicly connect the inner parts of the body directly to the outside. The role of the blood in insects is more akin to that of the lymph in vertebrae.
And this is one reason we don't see gigantic insects, quite aside from the usual argument that the square-cube law would make their limbs too thin to support their weight. It also means they would have to evolve better oxygen transport mechanisms.
Who is John Cabal?