Catenula evelinae sensu Marcus 1945

Catenula evelinae Marcus, 1945 Fig. 2 E – H Sampling site. Sphagnum sp. 2. Description. Animals reach a length of 800 μm in the two-zooid stage; chains longer than two zooids were not observed. The body is cylindrical, with a narrowing and pointed posterior end (Fig. 2 E). The head is not separated from the body; however, it has a clearly distinguishable tripartition (Fig. 2 E). The first thickening at the head occupies the anterior tip, and the last one lies in front of the mouth. On each of the three parts, rounded granular epidermal inclusions are present (Fig. 2 G). The third thickening is surrounded by a ciliated ring (Fig. 2 H) split into four furrows on the ventral side. The mouth opening is located behind the ciliated ring, leading to a pharynx shaped like a comb, similar to the one in C. turgida. Between the second and third thickening, there is a statocyst with a single, spherical statolith (Fig. 2 F). The gut was brownish in our specimens, but the inner lining of the intestine was not clearly distinguishable. The posterior end of the body is crenulated and resembles a tail (Fig. 2 E). The cilia layer is uniform and covers the whole animal; no stiff cilia were observed. The worms are very easily culturable on Chalkley’s Medium with wheat grain at 20 ° C. In the cultures, they swim freely in the water column or crawl in the sediment at the bottom of the dish and prey on bacteria and small protozoans. Distribution. Brazil, bromeliads from São Paulo, Pinheiros River meadow (Marcus 1945); Brazil, wetland in Rio Grande do Sul (Braccini et al. 2017).