I find the hypotrichous ciliate Stichotricha aculeata very frequently in some of my localities. In fresh samples, however, the loricae with the ciliates are difficult to detect as they are often mixed with detritus. It is therefore necessary to leave the samples for 1-2 weeks to allow individuals to colonize the walls of the jar. Stichotricha aculeata also likes to settle on the floating coverslip.

In my sampling sites, Stichotricha aculeata occurs together with the similar species Stichotricha secunda, which, however, has symbiotic algae and can therefore be reliably distinguished from Stichotricha aculeata. Interestingly, Kahl (1932) confused Stichotricha aculeata and Stichotricha secunda, which must have been an absolute exception. As a result, many misidentifications have been made. I base my identification on the descriptions by Foissner et al. (1991).

The characteristics of the individuals of my poulation of Stichotricha aculeata completely agree with the description of Foissner et al. except for the size. The specimens I examined were between 150–240 µm long and sometimes reached twice the length given by Foissner et al. In the literature there are only few data on the length of Stichotricha aculeata. Often the lengths given by earlier authors were adopted. On the Internet, however, you can also find specimens up to 290 µm in length. I therefore consider it likely that the size of my specimens is within the variance of this species.