New phylum discovered in 1983

The discovery of a new species is fairly big news, but that is nothing compared to the discovery of a new phylum. There are about 30 phyla in the animal kingdom (the number is somewhat approximate because biologists disagree about some classifications), of which our phylum, chordata is one. To put this in perspective, everything with a backbone or a reasonable facsimile, from sea squirts to us, is a chordate. To say that an animal is in a different phylum is to say that it has less in common with us than we have with sea squirts.

The discovery of Loricifera reads like a detective story, complete with unexpected plot turn. In 1982 Danish zoologist R.M. Kristensen was visiting the marine laboratory at Roscoff, France. It was his last day there, and he was in a hurry. He skipped over his established collection techniques and hastily washed his marine sediment sample with fresh water. Dislodged from their firm grip on tiny pieces of sediment by the osmotic shock were numerous examples of this tiny, previously unknown organism.

Loricifera are minute invertebrates, rarely attaining 0.5mm in size. They live firmly attached to rocky and shelly marine substrata. Their tiny size and solid attachment to the marine bed explain their late discovery. Since the initial discovery of Nanaloricus mysticus off the French coast by Kristensen, a further approximately twenty species of Loriciferan have been identified. The range for this phylum has also been extended to include the coastal regions of North America, and a global distribution seems likely.

The name Kristensen gave them means "corset bearers," and their hind ends are encased in a vase-shaped structure (the "lorica") constructed of six cuticular plates. A mouth cone sticks out the end, and can be withdrawn. Male and female genders are separate. They seem to have a well-developed brain. Some have called them "brush heads" from their appearance. Images are available on the internet.

As yet, Loricifera have never been observed alive; they can only been induced to relinquish their tight grip on the rock by a powerful osmotic shock with fresh water, which kills them. Accordingly little is known of their habits. Several larval forms have been found, together with empty loricas, which last suggest that growth and development are by molting. But most of what we know - or think we know - is mere guesswork.

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