The sort of habitat our mystery creature lives in, and the submersible that has tried to find it. DSV Alvin sets a lander basket with tube cores on the bottom. Note the encroaching darkness. Think of yourself living in that environment -- a soft mud bottom, and nothing but miles and miles of cold, inky blackness, as far as the eye can't see. Credit: National Oceanic and Atmospheric Administration/Department of Commerce

There are a few creatures on Earth we knew as fossils before we met face to face. Take the coelacanth. Scientists were shocked to discover a very much alive specimen of this be-lobe-finned fish hauled from the depths off South Africa in 1938. Prior to the discovery of this bit of rather irrefutable evidence, scientists believed the fish went the way of the dinosaurs (literally) at the end of the Cretaceous, 65 million years prior. Although not the first, Paleodictyon is probably the only member of this fossils-first group that was briefly considered to be evidence of some sort of alien deep sea race (hellooooo, Abyss) before it was connected to its fossil ancestors, essentially unchanged after 500 million years.

According to the article, scientists have suggested the hexagonal tubes they have found may be bacteria farms, worm burrows (or both), or the trace fossils of decayed compressed sponges that have long ago been scavanged. The paper even suggests such a sponge may have ties to the Ediacaran fauna, a class of bizarre creatures that preceeded the Cambrian Explosion. There’s one other candidate for Paleodictyon‘s identiy: a xenophyophore. They are the subject for another blog post, but the short, short version is that they’re gigantic single-celled organisms big enough to fit in the palm of your hand, which (like slime molds!) are multinucleate and feed by engulfment using pseudopodia, and (unlike slime molds) inhabit casings they put together with odd things lying around, including (sometimes) their own feces. In spite of being startlingly obscure, these things are apparently quite abundant on certain parts of the ocean floor. Still, this possibility doesn’t quite seem to fit the bill as no xenophyophore crunchy bits have ever been found in the hexagonal holes.

What about you, readers? What do you think Paleodictyon nodosum is? If you think you know the answer, write it on the side of a Deep Flight Super Falcon High Performance Winged Submersible with carbon fiber pressure hull, dual cockpit flight controls, heads-up instrumentation, and laser “collision avoidance feeler beams”, and mail it to Jennifer Frazer, General Delivery, Boulder, CO 80301. Or put it in the comments below (boooo-ring!). Creative answers encouraged!