A handful of strange mushroom-shaped animals discovered in the deep sea off Australia in the 1980s have finally been named by scientists. The organisms are so unique that they may rearrange the earliest branches of the animal family tree.

The animals, described for the first time Wednesday in the scientific journal PLOS ONE, cannot be classified to any existing animal group, though they resemble a few long-extinct species. "It's a very interesting surprise, and it poses lots and lots of questions," says Simon Conway Morris, a biologist at the U.K.'s University of Cambridge who studies early animal evolution.

Scientists have recently been debating the positions of the animals at the base of the family tree, and the new oddballs might