Euchlanis dilatata (Ehrenberg,1832)

Most likely ID: n.a.


Synonym: n.a.


Sampling location: Purren pond, Mainau pond, Ulmisried, Bussenried, Bündlisried, Simmelried


Phylogenetic tree: Euchlanis dilatata



  • body ovoid
  • dorsal plate in cross-section arc of a circle, with U-shaped notch posteriorly
  • ventral plate little smaller than dorsal plate, broadly rounded posteriorly
  • length of lorica 150–320 µm, width 130–255 µm
  • slender toes 50–100 µm long, parallel sided with a short tip
  • trophi with 8 club-shaped teeth (4 per uncus)
  • a pair of setae at the distal end of first foot segment
  • one eyespot with lens
Euchlanis dilatata

I find Euchlanis dilatata in almost all my sampling sites, mainly between floating water plants. Essential for the identification is the shape of the dorsal and ventral plate. In Euchlanis dilatata the dorsal plate is evenly curved in cross section, like a circular section and without keel. The ventral plate is smaller than the dorsal plate and evenly, broadly rounded at the posterior end. The long toes are narrow and parallel-sided. This rotifer is feeding on diatoms, desmids and small algae.


More images and information on Euchlanis dilatata: Michael Plewka-Freshwater life-Euchlanis dilatata


Fig. 1 a-c: Euchlanis dilatata. L = 315 µm (of lorica). Three focal planes of a freely swimming specimen. Obj. 20 X.


Fig. 2 a-b: Euchlanis dilatata. L = 274 µm (of lorica). Two focal planes from ventral. Note that the ventral plate (VP) is smaller than the dosal plate (DP). Obj. 40 X.


Fig. 3: Euchlanis dilatata. Dorsal view with the dorsal antenna (DA) and one of the two lateral antennae (LA). NT = nephredial tubes. Obj. 40 X.


Fig. 4: Euchlanis dilatata. The red eyespot (ES) with a lens (LE) in a strongly squashed specimen. Obj. 60 X.


Fig. 5 a-b: Euchlanis dilatata. Two focal planes of the trophi in a strongly squashed specimen. Note the club-shaped teeth (CT) of the unci. Obj. 60 X.