Difflugia corona with some spines and a number of teeth

 
Difflugia corona Wallich, 1864

Diagnosis: Test sub-spherical to spherical with a variable number (0-20, mean 5) of conical hollow spines inserted from the mid-line to the fundus part. Test composed of fine mineral grains, rounded particles of quartz and parts of diatom frustules, all agglutinated by organic cement. Aperture terminal, circular, with 9 to 15 denticulate lobes.

Dimensions: 140-320 µm (Leidy); 200-250 µm (Penard); 180-310 µm (Awerinzew); 180-230 µm (Cash); 155-200 µm(Hoogenraad & De Groot); 80-380 µm (Lahr & Lopes); my measurements 105-193 µm, mean 156 µm.

Ecology: in sediments, in sphagnum, on waterplants, often very common. This species has been found in icefield lakes high in the mountains (Monti 1906).

Remarks: Sometimes the shell has a tubercular structure as in D. tuberculata. The number of conical spines I counted in Dutch specimen is mostly 4-6.

Difflugia corona
Difflugia corona
Shell, dorsal and apertural view
Difflugia corona
Difflugia corona
Small spine, 33 µm long and spine with a mineral grain in the opening
Difflugia bidens
Drawing: Penard, in Faune Rhizopodique du Bassin du Léman, 1902
Aperture with 12 denticulate lobes.
Each lobe is a hollow structure at the outer most part.
Shell with tubercular structure
Shell with tubercular structure – stacked image

  

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