Grape sized cells pass for worms...

[Vekseid]

...in ancient fossilized sea beds.

Writing in Current Biology, researchers say the creature leaves tracks on the seabed which mirror fossilised tracks left up to 1.8 billion years ago.

Many palaeontologists believe only multi-celled organisms could have made these tracks.

This has been difficult to confirm as no multi-cellular fossils of such an age have ever been found.

...

This is rather stellar as, to my knowledge, it was the biggest 'missing link' in evolution so far - namely wtf was up with those 'worms'. If it turns out that they were not worms but in fact rather stellar single celled organisms, that makes the puzzle fit a great deal nicer.

[Will]

That's awesome.  I actually didn't even know about the Sterling formations.  Thanks for sharing!

[The Overlord]

That's incredible...a single cell organism can actually make it to this size? That's the order of several thousand times the size of the component cells in our own bodies. If they can get one of these intact they need to MRI it and see if it has all the component cell structures we're accustomed to.

Alleged endosymbiont structures such as mitochondria and chloroplasts contain their own genetic material separate of the nucleus, leading to the theory that these were independent organisms before being engulfed and assimilated into the structures of eukaryotic cells. We need to know what makes this thing tick, and just how primitive it is.

[Storiwyr]

That's incredible...a single cell organism can actually make it to this size? That's the order of several thousand times the size of the component cells in our own bodies. If they can get one of these intact they need to MRI it and see if it has all the component cell structures we're accustomed to.

Alleged endosymbiont structures such as mitochondria and chloroplasts contain their own genetic material separate of the nucleus, leading to the theory that these were independent organisms before being engulfed and assimilated into the structures of eukaryotic cells. We need to know what makes this thing tick, and just how primitive it is.

That was my thinking too. How can it support the necessary functions for life at that size? Cell size is supposed to be limited by diffusion rates for the chemicals needed to sustain metabolism.

I'm not quite sure what you're getting at with endosymbiont theory. Are you suggesting that if it's extremely primitive, it may not have mitochondria? I know there have already been some forms of life found that do not have mitochondria. I can't remember for sure if it was secondary loss or if they just never had them though ...

[Vekseid]

Many bacteria don't have mitochondria - mitochondria themselves are thought to have been so absorbed.

These are protists, however, and likely have extremely slow metabolisms - they move a millimeter on a good day, according to the article.

[The Overlord]

I'm not quite sure what you're getting at with endosymbiont theory. Are you suggesting that if it's extremely primitive, it may not have mitochondria? I know there have already been some forms of life found that do not have mitochondria. I can't remember for sure if it was secondary loss or if they just never had them though ...

Like Veks said, very simple structures like viruses do not have mitochondria and other organelles, but I'm curious exactly where this thing fits on the classification charts. A protist is a varied group of eukaryotic cells, what I'm asking is this a throwback to a very ancient time? Does it have a nucleus like a eukaryotic cell should but is so old that's lacking some of the other structures we accustom to such cells? I mean, things like the horseshoe crap go back hundreds of millions of years and have changed little, so this thing might be a true relic?

[Oniya]

That was my thinking too. How can it support the necessary functions for life at that size? Cell size is supposed to be limited by diffusion rates for the chemicals needed to sustain metabolism.

Even though it's a temporary state, remember that your average fertilized chicken egg is a single cell.  An ostrich egg is even bigger, and so the component cells as it divides would stay larger longer.

[The Overlord]

Even though it's a temporary state, remember that your average fertilized chicken egg is a single cell.  An ostrich egg is even bigger, and so the component cells as it divides would stay larger longer.

Point.