Microworld

world of amoeboid organisms

Menu
Polychaos dubium
Polychaos dubium, slender form, 200 µm

Polychaos dubium (Schaeffer, 1917)

In the early spring of 2012 and 2015 I found large number of specimens of Polychaos dubium in floating debris at several locations around the Naardermeer. These specimens were completely filled with food particles and large paired bodies, thus resembling a Pelomyxa species. Because they were filled with food particles, they probably didn’t show a more slender and palmate shape as is characteristic for Polychaos. At first sight these specimens are hard to distinguish from Pelomyxa, being broad and without pseudopodia and fully filled with food and debris. One specimen contained a large quartz particle. Only when they start to move, you can see that the monopodial form lacks the fountain streaming of Pelomyxa, though specimens which doesn’t adhere to the substrate, also show this fountain streaming.

Polychaos dubium
Polychaos dubium
Nucleus, 29 µm and uroid
Polychaos dubium
Locomotive form, 256 µm, with uroid (left), contractile vacuoles and numerous food particles.
Polychaos dubium
Stationary form; this specimen resembles a Pelomyxa with all its inclusions.
Polychaos dubium
Crystals in a specimen from the river Gard, France, 2019.
Polychaos dubium
Polychaos dubium
Paired bodies
Polychaos dubium
Polychaos dubium
Nucleus, aberrant form, 71 µm and nucleus 35 µm
Polychaos dubium
Polychaos dubium
Nucleus 44 µm, all four nuclei in specimens in the same sample.
Polychaos dubium
Detail with nucleus, contractile vacuole and characteristic uroid.
Polychaos dubium
Arrow points to the nucleus, 31 µm in diameter
Polychaos dubium
ca. 200 µm long
Polychaos dubium
Arrow points to the nucleus, 31 µm in diameter.
Polychaos dubium
Uroid with some longer villi.
Polychaos dubium
Polychaos dubium
Nucleus, with small ‘holes’ or lacunae in the nucleolar granules
Recent posts

Penardochlamys arcelloides

P. arcelloides – after Penard, 1904 Penardochlamys arcelloides  (Penard, 1904) Deflandre, 1953 Diagnosis: Colorless or very slightly yellowish envelope, bag or cauldron-shaped, very thin, chitinous,

Read More »

Haplomyxa spec

Fig. 1: Main cell body of specimen A, partly hidden by debris Haplomyxa sp. Three specimens were observed in a Petri dish, along with two

Read More »

Lachmannia spec.

“Lachmannia” spec., body length 127 µm “Lachmannia” spec. I found two cells, size about 125 µm when ovoid, with an organic-walled membranous test and a

Read More »

Diplophrys spec. 7

Diplophrys spec., with three tufts of filopodia Diplophrys spec. These cells are granular, never seen before. I found them in a sample from the Bert

Read More »

Psammonobiotus spec.

I found this specimen in a sample from the Oppad, near Hilversum, 2020. It is similar to Psammonobiotus linearis, but lacks a clear spine at

Read More »

Sphenoderia compressa

Sphenoderia compressa, after Badewitz, 2002 Sphenoderia compressa Badewitz, 2002 Diagnosis: Test ovoid, oval in cross section, hyaline, covered with relatively small, oval, rather irregularly arranged

Read More »