Dendrogramma, a #speciesoftheweek that could rewrite the tree of animal evolution
Almost 30 years ago, Biologist Jean Just and his colleagues took samples from the deep sea close to Australia. They used some kind of a wire-mesh cage, dragged by a rope on a ship, to skim the top layer of soil from the ocean floor at 400 and 1000 meter depth. These cages dug out and carried away everything that could not escape fast enough. Among the findings were mushroom-shaped organisms. And in 1986 the scientists had no clue what they had brought to their lab.
So the just a few millimeter sized creatures went the way of all still to be classified findings – and there had been a lot in the cages – it was conserved in the best possible way, in alcohol. Unfortunately, this conservation method is not approriate for any moleculobiological analysis after such a long time, to determine the species’ origin. But it was obvious to the researchers, that even though the organisms shares some of it’s features with comb jellies and Cnidaria it does not belong to either one of them. The species, they named Dendrogramma during the process, does neither feature stinging cells or tentacles (as Cnidaria) nor the typical sensory organs of comb jellies.
Now they know that they had discovered something very special, a new genus: Dendrogramma. And on top of that with two new species named Dendrogramma enigmatica and Dendrogramma discoides.
What does this discovery mean for the family tree of the animal species?
Having found animals that can not be classified to any existing animal group could help to get a clearer view on the evolution of animal kingdom at all. The National Geographic quotes Leonid Moroz, a neurobiologist at the University of Florida: If the new species turn out to be descendants of early animals, the find could “completely reshape the tree of life, and even our understanding of how animals evolved, how neurosystems evolved, how different tissues evolved.” An he adds: “It can rewrite whole textbooks in zoology.”
The research has only just begun.
DateSeptember 4, 2014