Pterocystis scaposa
From Siemensma, 1991

Pterocystis scaposa (Dürrschmidt, 1987) Siemensma, 1991

Diagnosis: Periplast, ca. 10 µm in diameter (measurement based on whole mount); details of protoplast unknown. Scales of two types. Plate scales, 1.2-1.5 X 0.6-0.8 µm, are patternless, except for a vestigially developed axial thickening. Spine scales, (1.1) 1.9-2.3 (7.2) µm long, consist of shaft, base-plate and lateral wings. Shaft narrow, non tubular, tapering to a blunt apex. Wings, ca. 0.08 µm broad, to be found on either side of the shaft. They are broadest just beyond the base-plate but then narrow gradually towards the distal end of the shaft. Base-plate, ca. 0.5 µm in dia­meter, reniform or heart-shaped, surrounded by a narrow peripheral rim.

Ecology: from the Banado Cruces, southern Chile (Dürrschmidt, 1985). Distribution: Chile, Sri Lanka.

Remarks: A. scaposa is remarkable in that two otherwise always separate charac­teristics are combined in its spine scales: lateral wings and heart-shaped base-plates.

Variation within A. scaposa is most noticeable with regard to the size of the spine scales. Whereas those from the majority of the Chilean habitats and from Sri Lanka vary from 1.9 to 2.3  µm, those from a swamp near Puerto Montt, Chile are 1.2 µm long. There is, however, no reason to believe that this difference should be considered anything but infraspecific variation. It may indicate the presence of different clones, or different stages in the cell or life cycle.

Recent posts

Difflugia key ovoid

Difflugia Group 1 Key characters: Test < 60 µm. Test in cross section rounded. Test with rounded fundus. Pseudostome with smooth circular edge. Test not

Read More »

Difflugia: ovoid tests

Difflugia – group 1 Test < 60 µm. Test in cross section rounded. Test with rounded fundus. Pseudostome with smooth circular edge. Test not spherical

Read More »

Difflugia ampla

Difflugia ampla, after Rampi, 1950 (l) and Gauthier-Lièvre et Thomas, 1958 (r) Difflugia ampla Rampi, 1950 Diagnosis: Test broadly pyriform, with a wide and rounded

Read More »

Difflugia parva

Difflugia parva, from Gauthier-Lièvre et Thomas, 1958 Difflugia parva  (Thomas, 1954) Ogden, 1983 = Difflugia oblonga var. parva Thomas, 1954 Diagnosis: Test pyriform, tapering evenly from

Read More »