Difflugia bidens
 
Two shells from the same sample, 310 µm (Naardermeer, Netherlands)

 

 

Difflugia bidens Penard, 1902

 

Diagnosis: test ovoid, compressed in cross-section, relatively smooth; fundus usually with 2-3 small spines; pseudostome large, circular, without collar; nucleus finely granulated, large, sometimes with a globular structure inside.

 

Dimensions: Penard 250-270 µm long. My measurements: 307-366 µm.

 

Ecology:I found several specimens in detritus from the bottom of ditches in the nature reserve Naardermeer in the Netherlands (GPS 52.281278 - 5.118853). This species has also been recorded for Hungary by Julia Török (1998) and for Canada.

 

Remarks: This species has usually two spines, hence the name bidens.

 

Difflugia bidens nucleus
Difflugia bidens nucleus
Nucleus, 80 µm in diameter; left: DIC, right: normal illumination
Difflugia bidens
Drawing: Penard in Faune Rhizopodique du Bassin du Léman, 1902
Difflugia bidens
Difflugia bidens, 366 µm, front and side view (Naardermeer, the Netherlands)
Difflugia bidens
Four Difflugia species in one sample; left: Difflugia bidens and right: Difflugia nodosa, Naardermeer, the Netherlands
Difflugia bidens, part of the shell
Difflugia bidens
Difflugia bidens, spine
Difflugia bidens
Difflugia bidens, from the Pénard Collection in Geneva - Photographed by Thierry Arnet, as part of the Pénard project (https://commons.wikimedia.org/w/index.php?curid=40497788)
Difflugia bidens
Difflugia bidens
D. bidens, 315 and 270 µm, Naardermeer, the Netherlands