Spirostomum teres

Macek, Miroslav, Medina, Ximena Sánchez, Picazo, Antonio, Peštová, Dana, Reyes, Fernando Bautista, Hernández, Jorge Ricardo Montiel, Alcocer, Javier, Ibarra, Martín Merino & Camacho, Antonio, 2020, Spirostomum teres: A Long Term Study of an Anoxic-Hypolimnion Population Feeding upon Photosynthesizing Microorganisms, Acta Protozoologica 59 (1), pp. 13-38 : 28

Spirostomum teres identification

Morphologically, the ciliates from all three lakes showed the same characteristics and, if observed in vivo, they were brown-yellowish with cortical granules but almost without visible large food particles that could change its colour.

Both in DAPI and protargol treated samples, the ciliature, membranells and morphology of cytostoma were in good agreement with the S. teres Cláparède & Lachmann, 1858 description ( López-Ochoterena 1966; Dra- gesco and Dragesco Kerneis 1986; Foissner et al. 1992; Şenler and Yildiz 2004; Fernandes and da Silva-Neto 2013; Boscaro et al. 2014; Shazib et al. 2016, 2019). However, the macronucleus was found more elongated and curved although not in such extent as for S. yagiui Shigenaka, 1959 . It should not be so surprising because the morphological species S. teres contains several molecular clades ( Boscaro et al. 2014; Shazib et al. 2016, 2019), which could be related to different environ- ments. But it is quite strange that almost the same mor- phology was observed in two Mexican populations, one from a hyposaline lake Alchichica (9 g L –1), the other from a freshwater lake La Preciosa (1.1 g L –1) and from a karstic lake La Cruz (Cuenca, Spain).