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

Yogsothoth carteri

Yogsothoth carteri, after Shishkin and Zlatogursky, 2018 Yogsothoth carteri Shishkin and Zlatogursky, 2018 Diagnosis: Individual cells in a colony have a diameter of 9.7-15.2 µm;

Read More »

Yogsothoth knorrus

Yogsothoth knorrus, after Shishkin and Zlatogursky, 2018 Yogsothoth knorrus Shishkin and Zlatogursky, 2018 Diagnosis: Individual cells in colony have a diameter of 5.53-13.26 µm; they

Read More »

Yogsothothidae

Yogsothoth carteri, from Shishkin and Zlatogursky, 2018 Yogsothothidae  Shishkin and Zlatogursky, 2018 Diagnosis: Centrohelids covered with two types of tangentially-oriented plate-scales, having a different morphology.

Read More »

Acanthocystis dürrschmidtidae

A. dürrschmidtidae – after Wujek, 2003 Acanthocystis dürrschmidtidae  Wujek, 2003 Diagnosis: Cells 35-40 µm (based on a whole mount). Periplast comprising scales of two types, plate

Read More »

Centroplasthelida

Centroplasthelida Febvre-Chevalier and Febvre, 1984   Diagnosis: Phagotrophic and non-photosynthetic protists with one large spherical or near spherical centrosome at the center of the cell

Read More »

Pterocystida

  Pterocystida Cavalier-Smith and Heyden, 2007 stat. n.   Phylogenetic diagnosis: The least inclusive clade, containing Pterocystis devonica, Raphidiophrys heterophryoidea and Choanocystis curvata, but not Acanthocystis

Read More »