‘Mushroom’ sea creature makes a new branch on the tree of life

BY Rebecca Jacobson  September 4, 2014 at 5:33 PM EST
An animal found in the ocean of the coast of Australia in 1986 has defied classification on the tree of life. Photo courtesy PLOS ONE

An animal found in the ocean of the coast of Australia in 1986 has defied classification on the tree of life. Photo courtesy PLOS ONE

A mushroom-shaped animal found deep in the ocean doesn’t fit anywhere on the tree of life.

Dendrogramma enigmatica and Dendrogramma discoides are only a few millimeters wide, with a wide disc at one end and long stalk with a mouth on the other end. And no one knows how to classify this new critter.

“Finding something like this is extremely rare, it’s maybe only happened about four times in the last 100 years,” said Jorgen Olesen of the University of Copenhagen. Olesen and his team published a study on the Dendrogramma in the academic journal PLOS One on Wednesday.

It’s possible that Dendrogramma is an ancient organism, leftover from early evolution.

“We think it belongs in the animal kingdom somewhere; the question is where,” Olesen told BBC News.

Newly discovered organisms are classified by their characteristics and sorted into different kingdoms such as animal, bacteria, fungi and plants. From there, they’re divided into phyla, which is determined by body design. Then living organisms are divided into classes, orders, families, genuses, species and subspecies.

Dendrogramma is multicellular, so it isn’t a bacteria. But its body isn’t symmetrical like many animals. Its gelatinous body is almost like a jellyfish, but it doesn’t meet the requirements for that phyla either, Olesen said.

Unfortunately, DNA analysis isn’t an option to classify the new animal. The specimens in the study were found in 1986 and preserved in an alcohol solution, destroying their genetic material for analysis. Olesen hopes the international scientific community can help come up with an answer.

“We published this paper in part as a cry for help,” Olesen said. “There might be somebody out there who can help place it.”