Gastropus stylifer (Imhof, 1891)
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Lake Constance
Phylogenetic tree: Gastropus stylifer
Diagnosis:
- length 102 – 242 µm
- laterally flattened
- body field bottle shaped
- ringed foot with two toes
- foot can be extended at the ventral side
- one eye spot in anterior third
- liquid in body cavity is colored pink
- stomach colored brown, green and blue due to prey (dinoflagellates)
- mastax with pre-pharyngeal tube
I have found Gastropus stylifer so far exclusively in the plankton of Lake Constance. The rotifer can be identified by its pouch-like shape and its beautiful pink, blue and yellow coloration. Gastropus stylifer feeds exclusively on dinoflagellates. These are sucked out with a pre-pharyngeal tube. The suction force is generated by the mastax, which is located almost in the middle of the body. The tube can be partially extended (s. fig. 2). As another special feature Gastropus stylifer has a ringed foot with two toes, which can be extended through an opening on the ventral side.
More images and information on Gastropus stylifer: Michael Plewka-Freshwater life-Gastropus stylifer
Fig. 1 a-c: Gastropus stylifer. L = 115 µm. A freely swimming specimen in lateral view from right. Note the extendable foot on the ventral side (F). Obj. 60 X.
Fig. 2: Gastropus stylifer. L = 122 µm. A freely swimming specimen with an extended pre-pharyngeal tube (PT) used to suck out dinoflagellates. 60 X.
Fig. 3 a-b: Gastropus stylifer. L = 115 µm. A freely swimming specimen in lateral view from right. Note the extendable foot on the ventral side (F). BL = bladder, PT = pre-pharyngeal tube, Vit = vitellarium. Obj. 60 X.
Fig. 4: Gastropus stylifer. L = 115 µm. A strongly squashed specimen. The pre-pharyngeal tube (PT) is pushed outside the specimen as a result of the pressure of the cover slip. ES = eye spot, TR = trophi. Obj. 100 X.