In August 2025 I found, in a several-weeks-old sample from the Schwemm Moor (Austria), a few specimens of the genus Spirotaenia that bears a strong resemblance to Spirotaenia endospira (s. fig. 1 a–b). However, there are two deviations from the described characteristics of Spirotaenia endospira (s. diagnosis above). The cells do have a length between 15–26 µm, but with a diameter of 4.5–5.0 µm (instead of 7–8 µm) they are very slender. In addition, the chloroplast in all cells shows at most a single twist. This is also the case in cells with a length of 26 µm.

All other characteristics agree with the description of Spirotaenia endospira. Because of these deviations, I would like to designate the find for now as Spirotaenia cf. endospira. Despite intensive searching, I was unable to find any further specimens in the sample container beyond those shown in fig. 1 a–b.