In 1986, an expedition off the South-East coast of Australia near Tasmania, from depths of between 400 and 1,000 metres, brought up some jelly-like creatures, which were seen to be unusual and immediately preserved in ethanol. Now they have been examined, and assigned to a new genus Dendrogramma (from their resemblance to a tree diagram), with two species D. enigmatica and D. discoides.

Here (picture attribution)are some labelled specimens of D. enigmatica: note that the creatures themselves are only two or three millimetres in size.



They do not possess left-right symmetry, so they do not belong in the Bilateria, a massive group which includes insects, molluscs, and ourselves. They show some resemblance to cnidarians (jellyfish, sea anemones) and to ctenophores (comb jellies), but don’t appear to fit well in either group, so maybe they are a completely new phylum. Some have noted a resemblance to things that were around in the Ediacaran period, but if they were that remote from all other present-day multicellular animals that would be a turn-up for the book.

The best way to place them would be genetic analysis, but since the specimens were first preserved in formaldehyde before being transferred to ethanol, their DNA will be horribly degraded, though it has been suggested that techniques similar to those used on Neanderthal DNA might succeed. Subsequent attempts to get new specimens from the ocean have so far been unsuccessful.

You can read more about them on BBC news, from Nature, and Wikipedia which gives a number of reactions from various leading palaeontologists. This is the original paper Reference: Just, J., Kristensen, R. M.&Olesen, J. PLoS ONE 9, e102976 (2014).

Reading about “mushroom-shaped animals” did have me wondering briefly if they might even be a completely distinct group somewhere between animals and fungi, which, as I learned recently, are closer to each other than either group is to plants. But that seems to be too far-fetched, exciting though it would be if that were so. So to finish I will leave you with a picture of some real mushrooms, which have appeared in Reading following a cool wet August.