Trichocerca porcellus Gosse, 1851
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Simmelried
Phylogenetic tree: Trichocerca porcellus
Diagnosis:
- body stocky, almost cylindrical and ventrally curved
- head separated from body
- anterior margin of lorica with two small teeth
- dorsal keel inconspicuous
- length 120–185 µm (with toes)
- two inward curved toes, of almost equal length
- two secondary, short toes (hard to see)
- one cervical eyespot
- distal end of left manubrium T-shaped
I usually find Trichocerca porcellus between floating plant masses. The body shape and the strongly ventrally curved toes may be characteristic, but a reliable classification is only possible via the trophi, as there is a risk of confusion with the very similar species Trichocerca intermedia. This species has similar dimensions and a similar appearance to Trichocerca porcellus, but the distal end of the left manubrium of Trichocerca intermedia is L-shaped and not T-shaped as in Trichocerca porcellus (s. fig. 2).
Trichocerca porcellus is described as a common and variable species. The variability is mainly related to the body size and the length of the two toes. These are usually almost the same length, but can also vary in length.
More images and information on Trichocerca porcellus: Michael Plewka-Freshwater life-Trichocerca porcellus
Fig. 1 a-d: Trichocerca porcellus. L = 117 µm (with toes). Different focal planes from left of a freely swimming specimen. BL = bladder, CG = cerebral ganglion, ES = eyespot, Int = intestinum, ST = stomach, TR = trophi. Obj. 60 X.
Fig. 2: Trichocerca porcellus. The trophi of the strongly squashed specimen as shown in fig. 1 a-d. Note the T-shaped distal end of the left manubrium (MA). FU = fulcrum. Obj. 100 X.
Fig. 3: Trichocerca porcellus. The toes (TO 1, TO 2) in a strongly squashed specimen and the two secondary toes (ST 1, ST 2). Obj. 100 X.