Collotheca atrochoides Wierzejski, 1893
Collotheca atrochoides, total view. The images of these specimens seem to be the first findings of this species since its discovery by Wierzejski in 1893. In contrast to other Collotheca species C. atrochoides does not produce a gelatinous sheath, but is free-living in the boundary layer betwen the water column and the anoxic mud of Sphagnum ponds.
Collotheca atrochoides, specimen with egg; juxtaposition of 3 positions: left: retracted foot; middle: extended corona; right extended foot which does not have an adhesive disk.
Here is a video of a living specimen.
Collotheca atrochoides, part of the corona. In contrast to Atrochus tentaculatus, which does not have cilia in the corona, the cilia of this species are up to 80 µm long.
Collotheca atrochoides, this species could be observed swallowing actively detritus flakes. The diet of this specimen is euglenid flagellates (Trachelomonas sp.), but also Phacus sp./ Euglena sp. or heterotrophic flagellates or rhodobacteria could be observed in the stomach. Mx: Mastax with trophi; PV: proventriculus; St: stomach.
Collotheca atrochoides, the uncinate trophi are different from the drawing of the trophi of Atrochus tentaculatus by Wierzejski.
Collotheca atrochoides, the foot can be retracted completely into the trunk. The triangles mark the border of the "pocket" into which the foot is retracted.
Collotheca atrochoides, embryo; this is one of the few monogonont rotifers which is ovoviviparous.
Images courtesy of Dr. Martin Kreutz; Litzelstetten.
Location: Simmelried near Konstanz(1); pond II
Habitat: in the boundary layer betwen the water and the anoxic mud (upper 10cm of the mud)
Date: 2014
freshwater life
marine life