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article imageCanadian researchers have discovered a new kind of organism

By Karen Graham     Nov 16, 2018 in Science
Halifax - Researchers at Dalhousie University have found evidence that suggests microbe hemimastigotes represent a major new branch of the evolutionary tree of life.
Dalhousie University graduate student Yana Eglit found two species of the organism in some dirt she collected on a whim while hiking with other students along the Bluff Wilderness Trail outside Halifax in Nova Scotia a couple years ago.
In their paper published in the journal Nature on November 14, the group of researchers describes their genetic study of the dirt-dwelling microbe.
A genetic analysis of the two organisms found they were so different from other living things they don't fit into the plant kingdom, the animal kingdom, or any other kingdom used to classify known organisms.
This is the part of the Bluff Wilderness Trail in Nova Scotia where graduate student Yana Eglit coll...
This is the part of the Bluff Wilderness Trail in Nova Scotia where graduate student Yana Eglit collected some dirt that ended up containing two species of rare hemimastigotes.
Yana Eglit
"They represent a major branch… that we didn't know we were missing," said Dalhousie biology professor Alastair Simpson, Eglit's supervisor and co-author of the new study, according to Phys.org. "There's nothing we know that's closely related to them."
The study describes the microbes as being "approximately two-hundredths of a millimeter long—they move using over a dozen flagella. And they survive by eating other microbes. It was the latter characteristic that led the team to name the species Hemimastix kukwesjijk, in honor of a hairy man-eating ogre from Mi'kmaq (native people in Nova Scotia) folklore."
Light microscopes show the two hemimastigotes  Spironema  left  and Hemimastix kukwesjijk  found in ...
Light microscopes show the two hemimastigotes, Spironema, left, and Hemimastix kukwesjijk, found in the same dish
Yana Eglit
Professor Simpson says we would have to go back at least one billion years - more than 500 million years before the first animal arose - to find a common ancestor of hemimastigotes.
Outside all established eukaryote supergroups
The research team places Hemimastigophora outside of all established eukaryote supergroups. "The previous ranking of Hemimastigophora as a phylum understates the evolutionary distinctiveness of this group, which has considerable importance for investigations into the deep-level evolutionary history of eukaryotic life," says the study.
Eukaryotes represent a tiny minority of all living things. However, due to their generally much larger size, Eukaryotes evolved approximately 1.6–2.1 billion years ago, during the Proterozoic eon. Because hemimastigotes have complex cells with mini-organs called organelles, this makes them part of the "domain" of organisms called eukaryotes rather than bacteria or archaea.
Hemimastix kukwesjijk feeds on its prey in this microscope image. It attacks the prey with harpoon-l...
Hemimastix kukwesjijk feeds on its prey in this microscope image. It attacks the prey with harpoon-like organs, then uses its flagella to bring the prey to its mouth, called a capitulum, and sucks out the juices or cytoplasm.
Yana Eglit
Eglit and fellow graduate student Gordon Lax, who specializes in genetic analyses of individual microbes, were able to get the creatures to not only eat but reproduce. Eglit discovered Hemimastix shoots little harpoons called extrusomes to attack prey such as Spumella, a relative of aquatic microbes called diatoms, reports CBC Canada.
They grasp their prey by wrapping their flagella around it and bring it to their "mouth," called a capitulum "as it presumably sucks its cytoplasm out," Eglit said. Once she knew what the creatures ate, she was able to feed and breed them in captivity. "We were able to domesticate it, in a way," Eglit said.
Eglit says it's "extremely exciting" that it's still possible to discover something so different from all known life on Earth. "It really shows how much more there is out there."
More about Hemimastigotes, eukaryote supergroups, Dalhousie university, Evolution, genetic analysis