Microworld

world of amoeboid organisms

Menu
Difflugia acuminata
Difflugia acuminata: left to right: 293 µm, 330 µm, 333 µm (drawing after Ehrenberg, 1838)

Difflugia acuminata Ehrenberg, 1838

Diagnosis: shell long, cylindrical, slightly tapering from the posterior to the anterior end; posterior end pointed or with a more or less long, hollow and open tube or spine; shell composed of mineral grains, more or less mixed with scales of diatoms; in sphagnum the test can be completely composed of diatoms; aperture circular.

Dimensions: In his original description Ehrenberg gives a length of 1/3 mm = 333 µm. He describes the test as being oval oblong (see his drawing above).
The late Dr. A.A. de Groot (pers. comm.) has found shells in Baarn, the Netherlands, which were 800 µm large!

Ecology: Freshwater, all kind of water types, ranging from oligotrophic till eutrophic.

Remarks: Difflugia acuminata is probably a polymorphic species. Without doubt several variations of Difflugia acuminata has been described as new species. On the other hand the name covers probably several real species which are light microscopically hard to distinguish from the main morphotype. The most discriminating character is the shape en length of the spine, but in fact we don’t know precisely how variable it is. Shells with relatively long spines have been described as Difflugia giganteacuminata and with a curved spine as Difflugia curvicaulis.

Difflugia acuminata
Shells of Difflugia acuminata differ in shape, structure and size (180-390 µm)
Difflugia acuminata
Shells in a sample from Lemmer, Friesland, ranging from 204-429 µm. It shows the variability of this species.
Difflugia acuminata
These shells came from one sample (Kortenhoef) and varied in size from 214-364 µm. The first five specimen seems closely related, the other two tests are different.
 Difflugia acuminata
These shells came from another sample (Strabrechtste heide, Eindhoven), ranging from 239-322 µm.
Difflugia acuminata
Shells from a sample from Lemmer, Friesland, ranging from 180-253 µm
Five shells from the same sample, from Crailoo, measuring 270 to 415 µm
Recent posts

Penardochlamys arcelloides

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

Read More »

Reticulomyxa hannae

R. hannae, plasmodium – photomicrograph Steffen Clauss Reticulomyxa hannae Völcker and Clauß, 2020 Diagnosis: Trophozoites surrounded by a very thin mucous envelope, with slowly moving plasmodia, variable

Read More »

Velamentofex saxonensis

V. saxonensis, feeding (photomicrograph Steffen Clauss) Velamentofex saxonensis Völcker and Clauß, 2020 Diagnosis: Trophozoites ovoid, 30-95 μm, granuloreticulopodia up to 1000 μm long. with a hyaline, thin

Read More »

Velamentofex tyrolensis

V. tyrolensis (photomicrograph Steffen Clauss) Velamentofex tyrolensis Völcker and Clauß, 2020 Diagnosis: Trophozoites ovoid, 98-125 μm, with reticulopodia up to 300 μm long, with a hyaline,

Read More »

Velamentofex berolinensis

V. berolinensis Velamentofex berolinensis Völcker and Clauß, 2020 Diagnosis: Trophozoites ovoid, 50-300 µm, with a hyaline, extremely flexible, membranous test. Nuclei numerous, 11.6-16.2 µm in diameter,

Read More »

Lieberkuehniidae

 Lieberkuehniidae  Siemensma, Holzmann, Apothéloz-Perret-Gentil, Clauß, Voelcker, Bettighofer, Khanipour Roshan, Walden, Dumack and Pawlowski, 2020 Diagnosis: Multinucleate organic-walled monothalamous foraminifera. Test very flexible, elongated to broadly

Read More »