world of amoeboid organisms


>Pterocystis jongsooparkii

P. jongsooparkii  – from Zagumyonnyi et al., 2020

Pterocystis jongsooparkii  Zagumyonnyi, Prokina et Tikhonenkov, 2020
Diagnosis: The diameter of living cells is 8.2-10.6 μm. Axopodia are two times longer than the cell diameter. Skeletal elements are represented by spine- and plate-scales. Spine-scales consist of a shaft and trapezoidal base (1.44-2.23 μm in the wide proximal part) formed by lateral and basal wings. The lateral wings are 1.60-2.43 μm in length. They gradually taper towards the shaft and abruptly terminate at the middle part of the shaft, forming “shoulders”. The shaft is not tapered, straight, and smooth in the distal part, 3.12-4.60 μm in length, 0.13-0.27 μm in diameter. There are five small rounded marginal teeth at the apex of the shaft. The proximal half of the shaft is connected with basal and lateral wings and curved, forming a scoop-like structure. The inner surface of the lateral wings contains about 10-15 parallel transverse slits. The sides of the lateral wings are bent out, and form a marginal rim 0.07-0.12 μm in diameter. Plate-scales are oval, 2.18-2.98 × 1.19-1.61 μm, with a medial thickening 1.31-2.21 × 0.25-0.39 μm. Marginal rim varies from almost not pronounced (0.04 μm in diameter) to rather wide (0.11 μm in diameter). The length to width ratio of the plate-scales is 1.63-2.13. Cysts formation is not recorded.

Ecology: Marine. Interstitial water within the sand on stony littoral of Jeodo island shore, the Sea of Japan, South Korea.

Remarks: Pterocystis jongsooparkii possesses some significant morphological peculiarities. Among the species of Pterocystis and Raineriophrys, the studied heliozoan is most similar to Pterocystis anapoda Siemensma et Roijackers, 1988 by the trapezoidal base of spine scales. However, P. anapoda is characterized by spine scales that are two times longer, 6.5–14.7 μm (Siemensma and Roijackers, 1988a; Prokina and Philippov, 2019). Distal tips of spine scales of P. anapoda are truncated, without any teeth, while our strain has five small rounded marginal teeth. Scales of P. jongsooparkii are also similar to those of Raineriophrys fortesca (Nicholls, 1983; Mikrjukov, 1999). Both species are characterized by the presence of marginal teeth on the non-tapering distal tip of the shaft, and they are similar in terms of the presence of the radial slits on the inner lateral wings as well as in the shape and size of plate scales. However, spine scales of R. fortesca are usually longer (up to 24.0 μm). Their lateral wings are triangular or circular in shape; the radial ribs are present on the basal wings.

Recent posts

Foraminifer drome

Unknown species, collected from the river Drôme, France, 2021 Unknown species September 2021, I found three specimens of an agglutinated foraminifer in a sample collected

Read More »

Cyclopyxis spec

Cyclopyxis spec., 168 µm Cyclopyxis spec. Diagnosis: Shell circular in ventral and dorsal view, more or less hemispherical in lateral view (height/diameter ≈ 0.5); lateral

Read More »

Difflugia fallax

Difflugia fallax, from Penard, 1902 Difflugia fallax Penard, 1890 Diagnosis: Shell hyaline or yellowish-greenish, black at low magnification, round in cross section, formed of a

Read More »

Zivkovicia compressoidea

Z. compressoidea, a-b after Chardez, 1958; c after Jung, 1942 Zivkovicia compressoidea  (Jung, 1942) new.comb. Basionym: Pontigulasia compressoidea Jung, 1942 Diagnosis: Shell ovoid and compressed,

Read More »

Zivkovicia flexa

Z. flexa, from Cash and Hopkinson, 1909 Zivkovicia flexa  (Cash and Hopkinson, 1909) Ogden, 1983 Basionym: Pontigulasia compressa var. flexa  Cash and Hopkinson, 1909 Diagnosis:

Read More »

Lagenodifflugia epiouxi

L. epiouxi, after Chardez, 1984 3 Lagenodifflugia epiouxi (Chardez, 1983) new comb. Basionym: Pontigulasia epiouxi Chardez, 1983 Diagnosis: Shell elongate, circular in cross-section or very

Read More »

Centropyxis lapponica

Centropyxis lapponica, after Grospietsch, 1954 Centropyxis lapponica  Grospietsch, 1954 Diagnosis: Shell nearly circular in circumference, without spines. Aperture clear square with rounded corners. Shell viewed

Read More »

Chaos spec. 6

Chaos spec., Crailoo, 2021 Chaos spec. This specimen was found in a samples from Crailoo, Netherlands. It was remarkable because of the absence of crystals.

Read More »

Bullinularia maxima

Bullinularia maxima – from Bobrov and Mazei, 2020 Bullinularia maxima Bobrov et Mazei, 2020 Diagnosis: Shell brown, opaque, elliptical in ventral view; ventral surface is

Read More »