Microcodon clavus Ehrenberg, 1830
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Ulmisried, Pond of the convent Hegne, Mühlhalden pond, Simmelried
Phylogenetic tree: Microcodon clavus
Diagnosis:
- body conical with strongly arched back
- corona heart-shaped
- length 170–204 µm
- epipharynx red or violet
- mastax colored yellowish
- cerebral ganglion large
- uncus with 5-6 teeth
- one eyespot (adjacent to cerebral ganglion)
- foot long and slender
- toes conical, slightly curved
Microcodon clavus is a very common rotifer in my samples, but it never occurs in masses. In the samples, the specimens gather near the surface and are easy to collect.
Microcodon clavus is immediately recognizable not only by its trumpet-shaped body, but especially by its striking red and purple-coloured epipharynx. The epipharynx sits on a yellow-colored mastax. The stomach is usually yellowish or orange in color. This coloration clearly sets it apart from other rotifers. It is not known why the epipharynx is so strikingly red and purple in color.
Microcodon clavus can swim very fast, but can also stand in one place at times. In doing so, an adhesive thread is formed on which it “trundles”. However, I have never been able to recognize this adhesive thread.
More images and information on Microcodon clavus: Michael Plewka-Freshwater life-Microcodon clavus
Fig. 1 a-c: Microcodon clavus. L = 184 µm. A freely swimming specimen from dorsal. Obj. 60 X.
Fig. 2 a-c: Microcodon clavus. L = 210 µm. A slightly squashed specimen from dorsal (a) and from left (b, c). Note the apical eyespot (ES) and the red and pink colored epipharynx (EP). Obj. 40 X.
Fig. 3 a-c: Microcodon clavus. L = 200 µm. A second slightly squashed specimen from right. BL = bladder, MA = mastax, ST = stomach, Vit = vitellarium. Obj. 60 X.
Fig. 4: Microcodon clavus. L = 194 µm. A slightly squashed specimen from left with the visible dorsal antenna (DA). Obj. 60 X.
Fig. 5: Microcodon clavus. The trophi and the red/pink colored epipharynx (EP) in a strongly squashed specimen. FU = fulcrum, UC = uncus. Obj. 100 X.