The Small World of Freshwater Gastrotrichs
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  • head five-lobed with elongated anterior lobe and cephalion
  • posterior lash almost circular, the two anterior ones reduced to tufts
  • lateral spines short, simple and only slightly curved
  • spines single or in small bundles, posterior ones not or only very slightly protruding the trunk
  • terminal spines of caudal lobes equally long and simple

9 Species:

Setopus abarbita

Setopus aequatorialis

Setopus bisetosus

140 µm - 150 µm
Dorsal scales: posterior setolae on small keel scales; terminal spine 45µm; spines in 5 groups of one short ventral spine (10-15 µm) and one longer lateral spine (ca. 40 µm); anterior and last group unpaired, i.e. 8 spines per side
Ventral scales: naked; only one pair of eyelashes; eyelash tufts on head typical

Setopus chatticus

Setopus dubius

Setopus iunctus

Setopus lemnicola

Setopus primus

120 µm - 186 µm
Dorsal scales: No scales; dorsolaterally 3 pairs of single, slightly curved spines (46µm); two simple terminal spines (40-54 µm).
Ventral scales: no scales; 4 eyelash tufts in two rows

Setopus tongiorgii

84 µm - 140 µm
Dorsal scales: Terminal spines with secondary apices on triangular scale rudiments; unequal in length (27-30 µm; 43-55 µm); numerous dorsolateral spines with secondary apices on scale rudiments; 21 per side.
Particularities: scaled ventral interciliate field