Pterocystis anapoda

 

From Siemensma, 1991

Pterocystis anapoda Siemensma & Roijackers, 1988

Diagnosis: Cell diameter c. 12 µm. Spine-scales 6.5-10.6 µm long, shaft 0.21-0.26 µm in diameter, cylindrical, hollow, with a blunt apex; proximal part of the shaft strongly bent; shaft with a membranous base divided in two wings; base 2.4-3.0 µm long and 1.6-2.5 µm wide; its trapezoid shape resembles a spade or duckfoot; laterally these wings show a slightly convoluted marginal area which becomes distally broader; upper surface of the basal membrane is fairly smooth, at the lower surface the shaft is pronounced with a slight indication of radial ribs on both sides of the shaft; some spine scale membranes show a slight basal depression.
Plate scales are 3.8-4.1 X 1.8-2.8 µm, broadly elliptical to ovoid, with a central depression with one longitudinal rib and several radial ribs; surface of the plate-scales smooth, with a small marginal rim.

Remarks: The specific name refers to the duckfoot-like structure of the spine scales. This species has been collected once in large numbers from a small eutrophic ditch near the town of Bolsward in the northern part of the Netherlands.
Pterocystis anapoda shows some resemblance to Pterocystis pinnata but differs from the latter in the shape of the spine-scales:

  1. the apex of P. pinnata is rather sharply pointed while the apex of P. anapoda is abruptly cut off;
  2. the basal membrane of P. anapoda is more or less flat while that of P. pinnata shows a deep tapering depression;
  3. the wings of P. pinnata extend along the shaft and terminate subapically, whereas the wings of P. anapoda do not extend along the shaft;
  4. the shaft of P. pinnata is rather straight whereas that of P. anapoda is strongly bent.
Pterocystis anapoda, spine scales
Pterocystis anapoda, spine scales and plate scale
Pterocystis anapoda, plate scales
Recent posts

Campascus cyphoderiformis

Campascus cyphoderiformis – After Chardez et Gaspar, 1984 Campascus cyphoderiformis  Chardez et Gaspar, 1984 Diagnosis: Test very clear, hyaline, consisting of endogenous scales of 1.2

Read More »

Campascus insterstitialis

Campascus interstitialis – After Golemansky, 1981 Campascus interstitialis  Golemansky, 1981 Diagnosis: Test elongated, in the shape of a bottle with a curved, colorless, transparent and

Read More »

Campascus triqueter

Campascus triqueter – After Penard, 1899 and 1891 Campascus triqueter  Penard, 1899 Diagnosis: Test brownish or yellowish, build of organic material embedded with a large

Read More »

Campascus bidens

Campascus bidens – After Krascheninnikov, 1923 Campascus bidens Krascheninnikov, 1923 Diagnosis: Test as C. minutus, but with, in ventral view, two small tooth-like projections, facing

Read More »

Campascus dentatus

Campascus dentatus – After Edmondson and Kingman, 1913 Campascus dentatus Edmondson and Kingman, 1913 Diagnosis: Shell of yellowish, chitinoid material similar in general outline to

Read More »

Campascus simcoei

Campascus simcoei – After Nicholls, 2003 Campascus simcoei Nicholls, 2003 Diagnosis: Protoplast is Cyphoderia-like, with long, branching, filose pseudopods and included numerous, small spherical reddish-orange

Read More »