Filinia longiseta (Ehrenberg, 1834)
Most likely ID: n.a.
Synonym: n. a.
Sampling location: Pond of waste disposal company Constance, Lake Constance, Mühlhalden pond, Hagstaffel pond
Phylogenetic tree: Filinia longiseta
Diagnosis:
- body sac-shaped, plump, anteriorly transversely truncated, without foot
- two long lateral setae situated near head
- one long ventral seta situated at posterior third
- length of body (without setae) 130–252 µm
- two eyespots with lenses
- vitellarium with 8 nuclei
- circumapical ring of cilia
- two unci each with about 26 theeth
- resting egg with bubble shaped surface
- planktonic lifestyle
Filinia longiseta is one of the most common rotifers in the plankton. The species can be identified very easily by the three long setae, which can be moved very fast by strong muscles, enabling Filinia longiseta to jump quickly. This species occurs only in spring and summer. In autum, restings eggs are formed, which remain in the mother’s body and sink to the bottom of the water when the mother dies. The next generation hatches from these eggs in the following year. Filinia longiseta has two eyespots, which are equipped with two small lenses (s. fig. 5).
More images and information on Filinia longiseta: Michael Plewka-Freshwater life-Filinia longiseta
Fig. 1 a-c: Filinia longiseta. L = 172 µm (without setae). Three focal planes from the right of a freely swimming specimen. Obj. 40 X.
Fig. 2 a-c: Filinia longiseta. L = 181 µm (without setae). Lateral view from the right (a, b) and left (c) of a second, freely swimming specimen. Obj. 40 X.
Fig. 3: Filinia longiseta. Dorsal view of a slightly squashed specimen. CC = circumapical ring of cilia, DA = dorsal antenna, LA = lateral antenna, RM = retractor muscle for lateral seta. Obj. 60 X.
Fig. 4: Filinia longiseta. The trophi (Tr) in a strongly squashed specimen. LA = lateral antenna, St = stomach, Vi = vitellarium. Obj. 60 X.
Fig. 5: Filinia longiseta. The pair of eyespots (ES) with lenses (LE) in a strongly squashed specimen. Obj. 60 X.