Chaetonotus (Zonochaeta) cf. trichostichodes Schwank, 1990

Schwank, Peter & Kånneby, Tobias, 2014, Contribution to the freshwater gastrotrich fauna of wetland areas of southwestern Ontario (Canada) with redescriptions of seven species and a check-list for North America, Zootaxa 3811 (4), pp. 463-490 : 475

Chaetonotus (Zonochaeta) cf. trichostichodes Schwank, 1990

Localities. A pond in the Puslinch district.

Material. 1 specimen.

A very small animal, only 90 µm in total body length. Unfortunately the single specimen was lost before sufficient observations could be made.

Body 18 µm at its widest point. Head with distinct cephalion and two pairs of short sensory ciliary tufts. Furca only 9–11 µm in total length. Scales are keeled and without spines; the edges are very hard to observe because of the small size. Nine to ten dorsal columns with approximately 18–20 scales in each column. In the middle of the trunk region, four straight simple spines, 18–20 µm, form a girdle. The dorsal scales lateral to the girdle have distinct spines, which are much shorter than the spines of the girdle. Two pairs of elongate spines are situated at the base of the furcal branches. The posterior pair 6–7 µm in length and the anterior pair 3–4 µm in length. A longer spine, 9–10 µm can be seen in the area of the caudal incision between the furcal branches. None of these 5 spines extend beyond the furcal branches.

Pharynx with two bulbs, the posterior one is twice the size of the anterior one.

The animal is very short and stumpy and therefore very similar to the small species Chaetonotus (Z.) trichostichodes Brunson, 1950 and Chaetonotus (Z.) pygmaeus Schwank, 1990 . However, both of those species have more reduced scales and 5 girdle spines compared to only 4 girdle spines in the studied specimen, and neither has elongated spines at the caudal end.