Pterocystis striata
From Siemensma, 1991

Pterocystis striata (Nicholls, 1983) Siemensma and Roijackers, 1988

Diagnosis: Cells 7-10 µm in diameter (fixed), with two kinds of scales. Spine-scales a hollow shaft, 3-7 µm long, 0.12-0.2 µm wide and tapered bluntly to a rounded apex. The proximal half of the spine shaft is bordered by an obovoid membrane with a peripherally thickened margin about 0.02 µm wide. The surface of the membrane is traversed with 20-42 radiating ribs (0.02 µm wide) connecting the margin of the membrane with the proximal half of the spine shaft. The base of the spine shaft is bent, drawing the central area of the membrane into a depression and imparting a spoon- or ladle-shaped appearance to the spine-scale. Plate-scales elliptical (1.4 x 2.2 µm) with a median tubular thickening approx. 0.07 µm wide with tapered ends and two-thirds the length of the scale. Edge of the scale ordered by a broad fold or thickened margin ca. one half  the width of the scale and patterned with numerous radially disposed ribs 0.02 µm wide. Similar ribs connect the median thickening to the scale margin.

Remarks: This species can be confused with A. pteracantha.

Pterocystis striata, plate scales were not visible. Rotes Wasser, Germany – Photomicrograph Eckhard Voelcker
Pterocystis striata, Rotes Wasser, Germany – Photomicrograph Eckhard Voelcker
Recent posts

Raphidocystis glabra

after Zlatogursky et al., 2018 Raphidocystis glabra Dürrschmidt, 1985 Diagnosis: Periplast 40-50 μm in diameter; spine-scales 4.6–15 μm; plate-scales 6-7 × 3-3.5 μm; tiny teeth

Read More »

Raphidocystidae

Raphidocystidae Zlatogursky, 2018 Diagnosis: centrohelids with monolayered plate-scales covering cell surface. Plate-scales with a hollow inflected margin. Sometimes trumpet-shaped or tubular spine-scales present, forming an

Read More »

Planhoogenraadia liboica

P. liboica – from Bonnet, 1979 Planhoogenraadia liboica Bonnet, 1979 Diagnosis: . Test relatively flat, with a dorsal convexity. Shell widest in the center. Aperture deep

Read More »

Deharvengia papuensis

Deharvengia papuensis, after Bonnet, 1979 Deharvengia papuensis  Bonnet, 1979 Diagnosis: Theca large, ovoid, very regular, colorless. Elliptical pseudostome bordered by a thick yellowish lip or

Read More »