Lagenodifflugia vas, 335 and 354 µm (Naardermeer, the Netherlands)

 

Lagenodifflugia vas (Leidy, 1874)

Diagnosis: Test pyriform, often with a well-marked constriction of the neck, frequently circular in cross-section but sometimes slightly compressed, composed mainly of agglutinated mineral particles bound by an organic cement: aperture terminal, circular: internally the shell is partitioned into two regions by a diaphragm constructed as part of the shell wall but having a single, usually central orifice. Nucleus with numerous nucleoli of different size, the largest ones in the periphery, intermigled with smaller ones; in general nucleoli are smaller towards the center.

Dimensions: Length 125-348 µm; nucleus 54 µm (n=1).  Leidy gives a test length of 2/5 mm = 400 µm.

Ecology: Freshwater, between water plants and in sediments; also in wet Sphagnum.

Remarks: The original description is of Joseph Leidy (1874): “Test composed of angular quartz particles, generally coarse, shape pyriform, with the neck constricted where it joins the body; fundus obtuse; mouth large, circular. Entosarc bright green from the abundance of chlorophyll granules. Length of test 2/5 mm.; neck one-fourth to one-third the length of the test. Abundant in Absecon Pond, New Jersey.”

Stump (1943) made a study of the nuclear division of the organism. During metaphase eight to twelve “chromosomes” form a well-defined equatorial plate; average time for completion of the division was found to be eighty minutes.

Resembling Difflugia pyriformis in appearance except for the deeply constricted neck.

Lagenodifflugia vas
Lagenodifflugia vas
Nucleus, 54 µm
Lagenodifflugia vas
Distribution of nucleoli in the periphery
Lagenodifflugia vas
Lagenodifflugia vas
Shell 332 µm, the arrow points to hole in the diaphragm. Apertural view, with the eccentric hole visible.
Lagenodifflugia vas
Lagenodifflugia vas
Lagenodifflugia vas
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