
Difflugia nodosa (Leidy, 1879)
Diagnosis, Shell 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: According to Penard (1902): Shell length 350—420 µm long. My measurements: 317—522 µm, nucleus Ø 50—70 µm.
Habitat: I found numerous specimens in sediments of ditches around the nature reserve Naardermeer, in Gaasterland, Diepveen, Bert Bospad, a forest pond at Groeneveld and a meadow pond in Limburg, 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 to 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.

















