In December 2022, I found a 162 µm long gastrotrich in the mud of the Simmelried, with features suggesting an assignment as Ichthydium bifasciale. The head is long oval and slightly narrowed towards the front. Apically, there is an almost rectangular cephalion that slightly protrudes (s. fig. 5). According to Schwank (1990), the soft cuticle of Ichthydium bifasciale is completely naked. Only a few species within the genus Ichthydium have a slight longitudinal striping on the dorsal side (e.g. Ichthydium fossae). However, in my specimen, I was able to recognize very delicate scales at high magnification, both on the dorsal and ventral sides (s. figs. 6 and 8). These very delicate scales are lanceolate, with a distal, simple spine (s. fig. 7). The scales are 12–15 µm long. The spines account for about 60% of the scale length. The spines overlap the lanceolate parts of the scales, giving the impression that they are keeled. However, this is not the case. Identical scales are found on the ventral side (s. fig. 9). The toes are very short, about 10 µm, and conically shaped (s. fig. 10). At the entrance of the intestine, a ring-shaped thickening can be seen, which is typical for the genus Ichthydium (s. fig. 4 b). The pharynx is almost cylindrical, without thickening, and about 40 µm long (s. fig. 4 a).

Although my specimen is about 15% longer than described by Schwank and delicate scales could be observed, it still appears to be Ichthydium bifasciale, as both the typical body shape with the elongated head and the shape of the intestine, pharynx, and furca match. My specimen is also identical to a specimen of Ichthydium bifasciale found and photographed by Dr. Michael Müller in 2019 (s. Mikroskopie Forum – Ichthydium bifasciale). However, he was unable to detect scales on his specimen, which may have been due to the fact that the images were taken with oblique lighting, which could not contrast the very delicate scales. Verification of whether the scales of Ichthydium bifasciale are a constant feature can only be verified with further findings.

The similar species Ichthydium brachykolon does not have a rectangular cephalion, the toes are significantly longer (17–18 µm), and the head is wider than the body. Additionally, the pharynx of Ichthydium brachykolon has a distinct thickening in the middle, and the body is somewhat smaller at about 130 µm.