Kariphilus muscorum was first described by Kahl (1931) as Saprophilus muscorum. Corliss (1960) transferred the species to the genus Sathrophilus, and Jankowski (2007) finally transferred it to the newly created genus Kariphilus. The only species in the genus established by Jankowski is Kariphilus muscorum.

I found Kariphilus muscorum in a moss sample in March 2021. Kahl also found the population he describes in a few lines in moss. The ciliate has a relatively large mouth opening compared to its body size, which is located in the anterior half. A membranelle of long cilia is visible inside. At 25–28 µm, my specimens were smaller than those described by Kahl (35 µm).

Apart from this deviation, all other characteristics correspond to Kahl’s description. Particularly striking and explicitly mentioned by Kahl is the short emptying canal of the subterminal contractile vacuole (s. fig. 1 c). In my specimens, I was able to identify isolated, rod-shaped extrusomes with a length of 1.8 µm (s. fig. 1 f). In the cytoplasm of various specimens, I was able to identify symbiotic bacteria, but these were difficult to contrast. The margin of the ciliate appears slightly wavy due to indentations where the cilia originate.