Plationus patulus (Müller, 1786)

Most likely ID: n.a.


Synonym: Brachionus patulus, Platyias patulus


Sampling location: Ulmisried, Simmelried


Phylogenetic tree: Plationus patulus



  • length 165 – 265 µm
  • anterior end of carapace with 10 spines
  • posterior end of lorica with 2 spines
  • dorsal side with fields and granulation
  • foot tripartite
  • 2 slender toes with pointed ends
  • one eyespot
  • foot opening surrounded by short spines
Plationus patulus

I found Plationus patulus in 1996 and 2005 exclusively in Simmlried. In my other finding areas I have been unableto detect the species. After 2005 I have not found any other specimen. Plationus patulus is easily recognized by the 10 spines on the front edge of the lorica (s. fig. 2). In contrast to species of the genus Brachionus the foot of Plationus patulus is not curled but jointed (s. figs. 1 and 3b).


More images and information of Plationus patulus: Michael Plewka-Freshwater life-Plationus patulus


Fig. 1: Plationus patulus. L = 288 µm (with foot). Ventral view of a slightly squashed specimen with a fully extended foot. Obj. 20 X.


Fig. 2: Plationus patulus. L = 275 µm (with foot). Ventral view of a slightly squashed specimen in brightfield illumination. Note the 10 spines at the anterior end of the lorica (1-10). Obj. 20 X.


Fig. 3 a-b: Plationus patulus. Two focal planes of the short spines surrounding the foot opening (arrows). FT = foot, LA = lateral antennae, TO = toes. Obj. 40 X.


Fig. 4: Plationus patulus. Ventral view with with the large red eyespot. Obj. 40 X.


Fig. 5: Plationus patulus. The trophi in a strongly squashed specimen. Obj. 100 X.