A new kind of animal, Dendrogramma, looks like a mushroom but does not fit into either the jellyfish or comb jelly family. It resembles fossils of some very ancient fauna. Their discovery could change the way scientists currently think organisms evolved.
The tiny animals, less than an inch long (two centimeters) when alive, are translucent and look superficially similar to chanterelle mushrooms.
But the relationship ends there. 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 specimens were collected in 1986 on the Australian continental slope off eastern Bass Strait and Tasmania. During sorting, they were recognized to be unique. The sampling of the bottom material is allowed by law and turns out to be a successful way to find brand new organisms unknown to science. When trying again to find the same organism in 1988, none appeared in the collection. It took until now to describe and publish the information on the find. Science moves slowly but that’s because it’s done carefully and done right.
Dendrogramma could be a whole new phylum.
The paper is free available on PLOS ONE: Dendrogramma, New Genus, with Two New Non-Bilaterian Species from the Marine Bathyal of Southeastern Australia (Animalia, Metazoa incertae sedis) – with Similarities to Some Medusoids from the Precambrian Ediacara.
A new genus, Dendrogramma, with two new species of multicellular, non-bilaterian, mesogleal animals with some bilateral aspects, D. enigmatica and D. discoides, are described from the south-east Australian bathyal (400 and 1000 metres depth). A new family, Dendrogrammatidae, is established for Dendrogramma. These mushroom-shaped organisms cannot be referred to either of the two phyla Ctenophora or Cnidaria at present, because they lack any specialised characters of these taxa. Resolving the phylogenetic position of Dendrogramma depends much on how the basal metazoan lineages (Ctenophora, Porifera, Placozoa, Cnidaria, and Bilateria) are related to each other, a question still under debate. At least Dendrogramma must have branched off before Bilateria and is possibly related to Ctenophora and/or Cnidaria. Dendrogramma, therefore, is referred to Metazoa incertae sedis. The specimens were fixed in neutral formaldehyde and stored in 80% ethanol and are not suitable for molecular analysis. We recommend, therefore, that attempts be made to secure new material for further study. Finally similarities between Dendrogramma and a group of Ediacaran (Vendian) medusoids are discussed.
Are they “living fossils”? That’s a problematic term that many scientists will not readily use, though the media loves it. Animals continue to evolve even though they may resemble their ancestors from long ago. The most famous example of what the media calls “a living fossil” is the coelacanth, a large fish that was known only from fossils until it was discovered alive in 1938. We currently do not know if Dendrogramma are similar genetically to those organism they resemble from the Ediacaran (circa 600 million years ago, give or take a few dozen million). We don’t have genetic material to compare, obviously. All that can be compared is the extant creatures to those in the fossil record.
Once again, the discovery of a new animal, a REALLY new animal as this one is, was not a cryptid (such as Bigfoot, Nessie or the chupacabra) that people think are out there but are never found. Instead, it’s scientists, who know how and what to look for, who are finding the interesting new beasties that give us new information on how life evolved. This is the most interesting creature found since the olinguito, probably more so due to its surprising nature.