Scanning electron micrograph of Idionectes vortex with flagellum

This microbe’s gumdrop-shaped body twirls crazily as it swims. Credit: S. Hess et al./Nature Microbiol.

Biophysics

Tiny flying saucers are actually odd new microbes

Single-celled life forms display original movement style.

A bizarre new microbe brings to mind the flying saucers of old films thanks to its unprecedented swimming technique.

The single-celled organism looks so unusual that, after its discovery, it was humorously dubbed UFO, for ‘unidentified flagellate organism’. Its formal scientific name is Idionectes vortex, or ‘peculiar swimmer with a vortex’. It is related to amoebae, but boasts a long, whip-like tail called a flagellum and can swim.

Sebastian Hess at the University of Cologne in Germany and his colleagues noticed that Idionectes twirls like a Frisbee as it progresses through water. It also spins its flagellum, which during movement is curved into a doughnut shape.

As the flagellum rotates, a film of water is dragged along the inner walls of the ‘doughnut hole’. This film then moves onto what would be the frosted part of a real doughnut, down its sides and back through the hole again. This circulating film of water creates a ring-like vortex that shoots Idionectes forward.

No other known organism uses this propulsive swimming technique.