Microworld

world of amoeboid organisms

Menu
Hyalosphenia ovalis, 147 µm; notice the keel and the many pores (c. 10) – Haaksbergerveen, The Netherlands

Hyalosphenia ovalis Wailes, 1912

Diagnosis: shell colorless to light yellow or brown, transparent, completely organic; in shape resembling a pouch or the blade of an axe, smooth and laterally flattened; usually with two lateral pores, one on each side, in the upper part of the shell; depending upon environmental conditions, up to 13 pores may be present in the borders of the fundus; aperture terminal, a narrow slit, surrounded by a small collar; protoplasm not filling the shell but attached to the inner surface by epipodia, always containing zoochlorellae; pseudopods often numerous active

Dimensions: length 110-140 µm

Ecology: Sphagnum; swamps.

Remarks: Booth and Mayers (2010) suggest that H. papilio is identical with H. ovalis: “Although early descriptions separated H. ovalis from H. papilio by its larger size, more oval shape, and rounded keel, some recent peatland work has focused more on the pronounced convex tapering of the aperture in H. ovalis (Charman et al. 2000). However, using this criterion, tests identified as H. ovalis are generally smaller than H. papilio, which is inconsistent with early descriptions. In fact, even specimens of H. ovalis in Penard’s slides at the British museum would be classified as H. papilio if the convex tapering of the aperture were used as the primary diagnostic feature (Charman et al. 2000). To add to the confusion, individuals of Nebela tincta sometimes lack plates, as is common in some modern samples and most fossil samples, yet these would be identified as H. ovalis using the approach of Charman et al. (2000). N. tincta is generally smaller than H. papilio, and confusion between these taxa may help explain the smaller size of tests identified as H. ovalis in recent studies (Charman et al. 2000).”

Reference: Booth, R.K. and Meyers, B., 2010. Environmental Controls on Pore Number in Hyalosphenia papilio: Implications for Paleoenvironmental Reconstruction. Acta Protozool. 49: 29-35

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 »