Sleighophrys pustulata was first described by Foissner from Venezuela in 2005. He found this species in samples from dried-up puddles on a cattle pasture. No other locations for this trachelophyllid ciliate have been known so far.

I found Sleighophrys pustulata in June 2026 in the Gieringer Weiher near Kitzbühel in Austria. This is a largely untouched raised bog. The samples were taken in shallow pools around the pond. In the samples, the specimens accumulated at the surface of the samples.

The most striking feature of Sleighophrys pustulata is an approximately 6–8 µm thick epicortical layer that covers the entire body of the ciliate, except for the apical mouth opening. The epicortical layer is a mucous layer into which intricately shaped scales, called lepidosomes, are embedded. In Sleighophrys pustulata, two different types of lepidosomes are present. Their exact shape can only be seen under an electron microscope. The larger form of these lepidosomes is roughly bell-shaped and can also be easily recognized under a light microscope (s. figs. 3, 4 and 5). In top view, they appear as dotted rings, similar to a bracelet (s. fig. 4). This corresponds exactly to the form as described by Foissner.

Another important feature is the size and shape of the extrusomes. Foissner observed larger, acicular shaped extrusomes with a length of 12–16 µm and a second form that is rod-shaped and only 2.5 µm long. In my populations, I was also able to observe these forms of extrusomes, but with slightly different lengths. The acicular extrusomes of type 1 were 10–11 µm long (s. fig. 3), while the rod-shaped extrusomes of type 2 were consistently 4.3 µm long (s. fig. 6). Since only one population from Venezuela has been studied so far, I consider these deviations to be the usual variability within the species.

The remaining features also corresponded to the description of Sleighophrys pustulata by Foissner. There are two widely separated macronuclei with an ellipsoidal shape, each with an attached micronucleus (s. fig. 3). The contractile vacuole is terminal (s. fig. 2 a). All the specimens I observed contracted under the coverslip, which caused them to take on a bottle shape and have a correspondingly shortened body length. However, this behavior was also observed by Foissner.