First ancestor of Humans and Animals

[Tom.G]

https://www.cnn.com/2020/03/23/world/animal-ancestor-ikaria-scn/index.html

Evidence of a worm-like creature about the size of a grain of rice has been uncovered in South Australia, and researchers believe it is the oldest ancestor on the family tree that includes humans and most animals.
The creature lived 555 million years ago.

Here is a link to the original article, but it's behind a pay wall.
https://www.pnas.org/content/early/2020/03/17/2001045117

Cheers,
Tom

 

[phinds]

Damn. I always thought the guy down the street was a bit of a worm, but you're tell me we all are?

 

[BillTre]

It was kind of expected that there would be bilaterialn during the Edicaran. Nice that they found one.
There are bilateral animals that don't fit the criteria they are using for bilateria (animals with two openings and a through-gut). Flatworms are bilateral, but have a gut with only a single opening, not a flow through gut.

Although most animals are bilateral, there are of course a lot of animals that are not bilateral, sponges, cnideria (jellyfish, corals, anemones) as well as a bunch of rather obscure "minor" phyla.
These are usually considered more "primitive", from which the bilateral animals would probably have been derived.

Yes @phinds, we are all worms in a cladistic sense.