Amoebae and relatives

Naked amoebae

Amoeba, Chaos, Pelomyxa and other lobose amoebae

Shape-shifting cells that creep by flowing into pseudopods. Large ones are a classic, if elusive, find.

Unidentified amoeba 2. Video: Keisotyo, CC BY-SA 4.0, via Wikimedia Commons.

What to look for

  • No fixed shape; cytoplasm streams forward into lobes.
  • Grainy interior with food vacuoles; a clear outer layer at the front of an advancing lobe.
  • Large species (Amoeba proteus, Chaos) reach half a millimetre or more when stretched out.

Size in the field

Large amoebae are visible at 40–100×, but look like a bit of debris until they move. Watch for slow flow.

Where to find it

On the bottom: the brown film on mud, decaying leaves and plant surfaces.

Clips 12

0:12Unidentified amoeba 2Naked amoebae 0:14Unidentified amoeba 1Naked amoebae 0:23Freshwater amoebaNaked amoebae 0:26Amoeboid movementNaked amoebae 0:25Amoeba proteusNaked amoebae 0:24Amoeba movement, time-lapseNaked amoebae 0:17Amoeba movementNaked amoebae 0:25Amoeba engulfing a diatom, excerpt 2Naked amoebae 0:25Amoeba engulfing a diatom, excerpt 1Naked amoebae 0:18Amoeba, clip 3Naked amoebae 0:19Amoeba, clip 2Naked amoebae 0:20Amoeba, clip 1Naked amoebae