An interesting genus of Gymnamoeba ("naked amoeba") is Korotnevella Goodkov 1988. The following two phase contrast images show an Korotnevella sp..
Korotnevella sp.
Korotnevella sp.
The amoeba has a single vesicular nucleus with a clearly distinguishable nucleolus. There are white lipid droplets and many small granules. Sometimes during locomotion I could observe a structure in the cytoplasm that looked like honeycombs. The granules were traveling around those "honeycombs". It is clear that amoeba have a cytoskeleton too, but this was the first time I saw features of it.
Although Korotnevella belongs to the "naked" amoeba, it is far from being naked! In fact Korotnevella wears a very particular "dress" made of many delicate and minute scales. The scales of this species are 250 nm in length, and will not show under a light microscope.
Korotnevella sp.
Korotnevella sp.
Korotnevella sp.
Korotnevella sp.
Here is some additional information on the family and the genera within. The family Paramoebidae Poche 1913 contains amoeba that have a single nucleus, can form finger-like pseudopodia (aka dactylopodia) and have scales or a cuticle on the glycocalyx. None of the species in this family is known to build cysts. Within the family Paramoebidae Poche 1913 we have 3 genera:
Paramoeba Schaudinn 1896
All known species in the genus are marine. Paramoeba have a clearly visible organelle next to the nucleus, the parasome or "Nebenkörper". The parasome contains DNA, can replicate itself and is believed to be the remains of an endosymbiont or endoparasite. Paramoeba are parasites that cause havoc in lobster, shrimp, sea urchin populations. Paramoeba have scales similar to Korotnevella.
Mayorella Schaeffer 1926
This genus contains amoeba that have no scales and no parasome. They are not "naked", too and their glycocalyx is covered with tiny columns.
Korotnevella Goodkov 1988
This genus was known as Dactylamoba Korotneff 1880. As all members of the family can form dactylopodia and the type species of the genus Dactylamoeba can not be rediscovered (the description is, by modern standards, to vague) Goodkov proposed the name Korotnevella Goodkov 1988 for amoeba that can form dactylopodia, have no parasome and scales on the glycocalyx.
The scales are made of polysaccharids and shaped like a boat. The species shown here has scales that do not match any published descriptions.
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