This article from Nature Ecology & Evolution is long and complicated, and is filled with technical details about paleontology and systematics, so I’ll just give a very brief summary and refer you to the BBC article below that, which is quite a good description of the paper’s results. Click on either headline to access the article, and go here to see the pdf of the scientific paper (reference at the bottom).
The paper:
The BBC article:
The paper reports the discovery of an ancient cnidarian, a relative of modern jellyfish, in an Ediacran fossil bed, located in Charnwood forest in Leicestershire, and dating about 560 million years ago. That was before the Cambrian Explosion, and some of the fossils in that bed don’t resemble any ancient animals—in fact, we don’t even know if they’re animals.
This one, however, appears to be a progenitor (“crown group fossil”) of modern Cnidarians, a living phylum that includes jellyfish, corals, and an obscure parasite. And the fossil, named Auroalumina attenbroughii (after David Attenborough), appears to be in the subphylum Medusozoa, which comprises mostly jellyfish and a few other bits and bobs. Nearly all Medusozoans begin life with a sessile stage affixed to the substrate, and then form free-swimming “medusas” that are the adult, sexual stage. They are all predators, catching prey with stinging tentacles.
This, then, would be the earliest predator known to us from the fossil record.
The fossil, shown below from the paper and then in a reconstruction, is identified by Dunn et al. as the sessile stage of medusozoans, before the free-swimming stage is formed. It consists of two “goblets” with tentacles, fastened together by a stem. It resembles modern species, and phylogenetic analysis of its traits make it likely that this was in the “crown group” of cnidarians—that is, it is closely related to the ancestor of all living cnidarians. This shows that the group existed in the Ediacaran—before the Cambrian explosion. As I’ve said, this makes it the earliest identified predator in the fossil record.
Here are the impression fossils and their outline in a BBC illustration:
An interpretation from the paper. The goblet-structure is about 20 cm long, or roughly 8 inches:
An interpretation from the paper as well as the BBC report:
And here’s the specimen right next to the enigmatic Charnia masoni, a frondlike organism from the Edicaran. We don’t have any idea what Charnia is, but it’s more likely to be a sessile animal than a plant, and whether it evolved into groups that are still with us, or went extinct without issue, is debated among paleontologists. We’re much surer about A. attenboroughii!
Charnia is famous as the very first fossil found in rocks that were Precambrian; below is a reconstruction from Wikipedia. The Ediacaran fauna, which lived from 635–538.8 million years ago, remains pretty much of a mystery: it comprises fronds, tubes, and discs, bags, and toroids, none of which we can place phylogenetically. They disappeared, and either evolved into modern forms around the time of the Cambrian explosion” or more likely, constituted a fauna whose members mostly went extinct.
The upshot: We have something that is close to the ancestor of all modern Cnidarians (it could be the common ancestor, but we’ll never know). It is the oldest known predator, though it’s possible that ctenophores (comb jellies) which lived back then and some of which are semi-predatory now, could have been predacious about the same time—or earlier. What we do know is that ancestors of modern cnidarians lived before the Cambrian explosion, which occurred roughly 540 million years ago and produced a radiation of many groups of multicellular organisms.
The BBC article quotes a scientist on the significance of the fossil:
“This is the cast-iron evidence of modern-looking organisms in the Pre-Cambrian. That means the fuse for the Cambrian explosion was probably quite long,” said Dr Phil Wilby, palaeontology leader at the British Geological Survey.
Well, I’m not sure what he means by “fuse,” or whether 20 million years is a long fuse, but surely the fuse—the ancestor whose descendants were part of the Cambrian explosion—was a lot longer than that. After all, the ancestor of all living species lived over 3.5 billion years ago, and so “fuse” was very, very long!
h/t: Pyers
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Dunn, F.S., Kenchington, C.G., Parry, L.A. et al. 2022. A crown-group cnidarian from the Ediacaran of Charnwood Forest, UK. Nat Ecol Evol. https://doi.org/10.1038/s41559-022-01807-x
Cool!
I think the “obscure parasite” is the Myxozoa? I always include these in my cnidarian lectures because there are thousands of species, and they’re ecologically important parasites of fish. Not exactly obscure, but very small (single cells or spores with a handful of cells). Amazing example of loss of complexity in parasites.
That is of course interesting.
One could speculate that predation evolved in deep water, where there wasn’t enough light to support photosynthesis.
Of course, without photosynthesis, the local biological productivity is relatively low. So the predators have considerably less to eat.
Caveat : mineral seeps, hot or cold. But I’ve never heard of any of mineralogical evidence for such an environment of deposition for the Chenjiang, Burgess, Charnwood, or Sirius Passet faunas (second thoughts : the original Ediacaran find was made in an unsuccessful mineral prospecting programme ; and the Siberian finds are in fairly diverse environments). Those mineral seeps are strongly associated with (surprise!) valuable metal deposits – there is a lot of surveying work looking for them, and fossils are the cheapest and most reliable way of understanding the fine dating of pay versus gangue beds in such deposits.
Re : “fuse” : most people think that whatever the Ediacaran fauna (as opposed to the time period) was, it isn’t particularly closely related to any modern phylum (with a distinct group thinking that they may be phylogenetically “near to” the Placozoa. Which would leave a branch of the (animal) family tree between the differentiation of the “Eumetazoa” and the common ancestor of Placozoa (or whatever is the closest relative of the Ediacaran fauna) and Eumetazoa : that branch is (I think) the “fuse” they’re referring to.
How long that branch (“fuse”) took to burn remains unclear. The dating of this fossil gives a minimum “fuse” of about 20 million years. But the maximum? Well there are putative trace fossils of (arguably) burrowing organisms dating back to 900 to 1500 Myr (Horodyskia) ; if (a real “if”) that is an eumetazoan, then that would give a “fuse” of 300 to 900 Myr. And would still leave open the question of why the Ediacaran were relatively well represented in the fossil record for about 100 million years, but not before or after then.
How long is 20 Myr? One third of the radiation of mammals after the bigger dinosaurs died out. About as long as the gap between the Sirius Passet (or Chenjiang) faunas and the well-known Burgess Shale fauna. Maybe half as long as the (north) Atlantic has been opening between Charnwood and Mistaken Point (Ediacaran fossil sites). Or in humano-centric terms, three times the approximate time between now and the last common ancestor of chimpanzees.
It’s worth emphasising that the fossil was “uncovered” in 2007, and it has taken 15 years to examine, interpret and publish. The wording is careful : I suspect the fossil is still in the field, and quite possibly covered back up. Which would imply two other things
– they took molds from the rock surface, which is routine for recording the Ediacaran these days ; far less damaging than trying to mine them out, and destroying a specimen (mineral, fossil) while trying to dig it out is a growing experience for embryonic geologists..
– the photo in the press pack is of a rock slab in a Charnwood quarry, which is nowhere near where the actual fossil was found (and may still reside.
A wonderful find, and His Attenboroughness sounds appropriately chuffed to have been given the naming gong to add to his collection of species and genera. I must move a visit to Charnwood up the “to do list” for the next time I’m in Central Englandshire.
But what does the newly-found fossil of the first predator tell us about God?
Sorry, couldn’t help the non sequitur rhetorical question, relevant to the other post from today.
The Fall began long long ago.
Interesting! I had a brief passing mention on BBC Radio 4, but was busy in the kitchen and forgot to look it up later.
Neat…you know, I’ve never really considered the “first predator”. Thought provoking discovery.
I live on the edge of Charnwood Forest. And I thought I was getting on a bit.
I’d think that any animal that had no chloroplasts could be considered a predator (or scavenger), nearly by definition. Amoebas and other unicellulars (I presume they antedate cnidarians or ctenophores) may be older predators.
What wonderful fossils though!