Animal of the Week September 9, 2014 -- a whole new...

Well, maybe it's a phylum, but the people who have described this week's animal of the week, two species in the new genus Dendrogramma (in the new family Dendrogrammatidae), aren't so bold as to create such a high level taxon. But if the suspicion that these organisms are most closely related to species thought to have gone extinct 540 million years ago is borne out, we'll have to change how we think about the history of life on earth...a bit.

They do look like mushrooms. © 2014 Just et al

The two species were found during examination of specimens connected from the deep sea continental slope of Australia in 1986, but have only now just been described fully in a paper published in PLoS One. Superficially they look like mushrooms, but the specimens available show they have a skin and a gut separated by jelly like material.

Unfortunately the preparation of the specimens in pure strong alcohol means that genetic material no longer exists for phylogenetic analysis. Later drying out and preparation with pure alcohol led to shrinkage and more changes in the physical structure, hampering further investigations. More specimens will be needed to see where these organisms hang on the tree of life. (Fortunately, I've got a birth certificate so while I have been prepared in copious amounts of alcohol [and possibly formalin in my most desperate moments] my position on the tree of life is well established.)

The researchers note similarities with the Ediacaran (or Vendian) fauna, ancient extinct organisms known from some of the oldest fossils that were thought to represent failed early experiments in the animal kingdom. If these new species are related to those animals, our understanding that they all died out will have to be rethought.

On divisions of life
A phylum is a group of organisms with a basic body plan that are distinct from other phylums. For example, humans are joined in the phylum Chordata with fish, frogs, birds, dinosaurs and sea squirts, all because at some point in their lifecycle they possess a tail with notochord backbone. Discovery of new species is remarkable enough, genera pretty special, families thoroughly exciting and any higher level distinction incredibly rare in this day and age...but who knows what else is out there.

Mnemonic for recalling the divisions of life
King Philip can only find green socks
Kingdom (eg, animal), phylum (eg, chordates), class (eg, mammals), order (eg, carnivores), family (eg, cats), genus (eg, big cats), species (eg, tiger)