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article imageOp-Ed: Billion year old predators? Outsider microbes rewrite life

By Paul Wallis     Nov 17, 2018 in Science
Halifax - A group of microbes called Hemimastigotes has been known, and unclassifiable as any plant, animal or anything else, for some time. New work has defined it as a separate kingdom… And thrown a rather large spanner into the view of life on ancient Earth.
This new kingdom includes active predators. That’s a somewhat jarring note in the otherwise rosy picture of microbes roaming around doing microbe things, passively absorbing and processing nutrients, etc. Predation requires a pretty complex, highly active ecology. It also requires access to protein and energy, meaning a truly advanced set of ecological requirements.
Also very much to the point, they’re eukaryotes, multi celled. Eukaryotes are supposed to be the next step up from single celled protists, and this is a true mystery. Did Hemimastigotes take that critical eukaryotic step, but on a totally different, long gone, evolutionary ladder?
Eukaryotes are believed to have evolved in the 2 billion year range, but of course there are some issues with what evolved, when, and where, and it may be that Hemimastigotes is a very important clue in those contexts. Given the difficulties of finding fossils this old, let alone micro fossils, the theory of the rise of eukaryotes is predictably a bit hazy. If Hemimastigotes are a billion years old, there is now at least a theoretical time frame and potentially a new, different, ecosystem to work with, too. Don’t be too surprised to find the catchy term ‘forensic paleo biology” to be lapping on the shores of scientific publications pretty regularly. It’s going to take some damn good research to pin all this down.
Alien? Not very likely.
The very major deal, of course, is not being classifiable as plant, animal, or any of the other forms of life on Earth. Alien? Almost certainly not. To be classified as alien, it’s reasonable to expect different DNA or equivalents, etc. That’s evidently not the case with Hemimastigotes, raising yet another range of questions. Not least of those questions is how do you get a whole kingdom developing so differently from the same DNA resources?
Ironically, the sheer 100% difference of Hemimastigotes does support one very well known theory about the origins of life on Earth. Earth is known to have been very different billions of years ago. It was a totally different environment. Modern families of species date back to the Pre-Cambrian, over 500 million years ago. Hemimastigotes precede that by over double that period of time.
The logic goes, therefore, that modern forms of life as we know them simply couldn’t have existed back then. The environment was totally wrong for them. If there was life, something else, therefore, would have to have existed. This new kingdom of oddball eukaryotes could well be a first glimpse of that life.
A strange, but strangely efficient, family
The Hemimastigotes family currently consists of 10 known species under the name Spironemidae, and they’re classified further with the description “heterotrophic flagellates” meaning they can’t produce their own food internally and source either from a primary source or from some other organism (heterotrophics) and have flagella, whip like appendages . This description of the obvious, however, also asks the question about exactly what the Hemimastigotes were eating a billion years ago, and that’s not too clear, either.
Canadian researchers from Dalhousie University hit the jackpot. They found two different species together on the Bluff Wilderness Trail in Nova Scotia, including the rather dramatic Hemimastix kukwesjijk species, pictured, which looks like a very focused flea/jellyfish and acts like a squid. It has flagellates, swimming tendrils, and uses them for both movement and to drag food in to its mouth, sucking out the interior cytoplasm and nutrients. Pretty advanced, even for animals which came hundreds of millions of years later. Manipulating objects doesn’t “just happen”, either.
This is no hick prokaryote at work, obviously. The method of feeding alone has to have had quite a lineage tacked on to it. The method of predation is efficient, suggesting a lot of adaption, and quite possibly a good general purpose prey range. The prey are also classic diatoms and other creatures known to have existed on ancient Earth. Hemimastix kukwesjijk clearly plays with pretty much a full deck, in terms of functionality.
Another question is way less obvious, but important: How did these strange creatures survive, and transition from a totally different, almost entirely unsuspected, ecology to multiple different ecologies for 500 million years? They’ve survived multiple mass extinctions which annihilated 99% of ancient life. They even seem to be doing OK in the Anthropocene, the human era, arguably one of the more toxic environments in Earth’s history.
One thing for sure – The new kingdom will provide biology, ecology, and related sciences with invaluable learning tools. The sound of jaws dropping will not be a coincidence.
This opinion article was written by an independent writer. The opinions and views expressed herein are those of the author and are not necessarily intended to reflect those of
More about Hemimastigotes, eukaryotes, Spironemidae, Dalhousie university, pre Cambrian life
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