I find Chaetonotus macrochaetus frequently and regularly in the Purren pond and the Simmelried. Mainly in the mud layer, but also in decaying plant masses. The species is quite characteristic with its long and thick spines, which have a small, distal secondary tip (s. fig. 6). The scales are trilobed and about 10 µm long in the middle of the body (s. fig. 5). All dorsal scales bear a spine, except for a field of small, keeled scales at the posterior end (s. fig. 7). On the ventral side there are small keeled scales and two elongate terminal scales that are also keeled (s. fig. 8). The ventral scales are supposed to be disc-shaped according to Schwank and Bartsch, 1990 (s. Literature). In my specimens they were rather oval and also oblong shaped, with a length of 3–4 µm (s. fig. 8).

A very similar species to Chaetonotus macrochaetus is Chaetonotus persetosus. The distinguishing features from Chaetonotus macrochaetus seem to be only minor. For example, the spines of the trunk are shorter and the ventral scales are slightly hexagonal in shape and lack a keel. My specimens had clearly keeled ventral scales, so Chaetonotus macrochaetus must be present here.