Dendrogramma enigmatica. Picture credit: Jorgen Olesen.
In an extremely rare event, a genus new to science has been described. Bizarre mushroom-shaped animals were found in the sea off south-east Australia at depths between 400 and 1000 meters in the mid-1980s, and have only now been scientifically categorized. The animals are so different from any other living creature that they have been assigned their own genus, called Dendrogramma.
Genus Dendrogramma contains two species, D. enigmatica and D. discoides. The organisms are so distinct to any other type of creature that the genus even has its own family, Dendrogrammatidae, as they defy classification into any other family.
The two physically closest phyla are Ctenophora and Cnidaria, but the new species differ from both as they lack the specialized characteristics of those animal groups.
The two members of the new genus are described in a paper published in research journal Plos One. Lead scientist Dr Jorgen Oleson on the paper said: "New mushroom-shaped animals from the deep sea have been discovered which could not be placed in any recognized group of animals.
"Two species are recognised and current evidence suggest that they represent an early branch on the tree of life, with similarities to the 600 million-year-old extinct Ediacara fauna."
The National Geographic describes the creatures:
"What looks like a mushroom's stalk on Dendrogramma has a mouth at the base leading to a digestive canal that forks repeatedly once it reaches a disk, which looks like a mushroom cap.
"The animals' lifestyle is as mysterious as their appearance. None of the specimens showed signs of having been torn from something else, leading researchers to think the animals are free-living, rather than attaching to a surface or each other."
"The animals' lifestyle is as mysterious as their appearance. None of the specimens showed signs of having been torn from something else, leading researchers to think the animals are free-living, rather than attaching to a surface or each other."
The same source goes on to report that the discovery may rewrite zoology textbooks, as the genus may represent an early evolutionary stage not accounted for by our current understanding of how life developed on Earth.
The closest animals to Dendrogramma spp. are known only from the fossil record and became extinct 540 million years ago, at the tail-end of the Ediacaran Era. Could Dendrogramma spp. have evolved the same channeled disk-shaped body independently, perhaps as a result to the same environmental pressures? If not, the new species may be descendants of those ancient life-forms.
