Difflugia nodosa
Difflugia nodosa complex, 356 µm (Naardermeer) l. and 522 µm (Groeneveld) r.

 
Difflugia nodosa (Leidy, 1879)

Diagnosis: Test large, robust, pyriform, compressed in cross-section; fundus with 1-4 blunt conical projections; zoochlorellae present; nucleus large, spherical with large and small granules.

Dimensions: Penard 350-420 µm long. My measurements: 317-522 µm, nucleus Ø 50-70 µm.

Ecology: I found numerous specimens in sediments of ditches around the nature reserve Naardermeer, in Gaasterland, Diepveen, Bert Bospad and in a forest pond at Groeneveld, all in the Netherlands. Locally not rare.

Remarks: This species was first described by Leidy (1879) as a variety of Difflugia (pyriformis) oblonga. Cash (1909) described a new species, Difflugia crassa, but this species is probably identical with Difflugia nodosa. The photomicrographs on this page probably show different species.

DNA-research (Blandenier et al., 2017) showed that D. nodosa is a cryptic morphospecies including at least two species.

Difflugia nodosa
 
Difflugia nodosa, 368-392 µm, Diepveen, where I’ve also found tests up to 470 µm
Difflugia nodosa
 
Difflugia nodosa, 314-440 µm, Diepveen
Difflugia nodosa
Difflugia nodosa
Nucleus of D. nodosa, 50 µm in diameter, in DIC (left) and normal illumination.
Difflugia nodosa
Difflugia nodosa
Nucleus of D. nodosa, 60 µm in diameter – from Diepveen.
Difflugia nodosa - Ferry Siemensma
Difflugia nodosa, 390 µm, Naardermeer, l., and 415 µm, Groeneveld, Baarn, r.
Difflugia nodosa
Difflugia nodosa, 317-400 µm – Naardermeer, Netherlands
Difflugia nodosa
Difflugia nodosa, 400 µm-490 µm – Groeneveld, the Netherlands
Difflugia nodosa
Difflugia nodosa, 390 µm (left) and 336 µm, Naardermeer, the Netherlands
Difflugia nodosa
Some isolated shells from Groeneveld, all c. 450 µm.
Difflugia nodosa
Difflugia nodosa, about 450 µm, Groeneveld
Difflugia nodosa
Difflugia nodosa
Difflugia nodosa, 450 µm, Groeneveld, l., and 322 µm, Kortenhoefse Plassen, r.
Difflugia nodosa, 470 µm – Den Treek, the Netherlands
Difflugia nodosa
D. nodosa, 480 µm – Crailoo, the Netherlands

 

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