Pseudisotoma monochaeta (Kos, 1942) Isotoma sensibilis var. monochaeta Kos, 1942: 125. Pseudoisotoma unipila Stach, 1947: 321. Pseudisotoma monochaeta – Stach 1947: 316. MATERIAL EXAMINED. — Spain • 10 specimens; SSD-1, slides 05, 07, 09 and 10; Ortuño et al. leg.; MZNA • 2 specimens on slide and 6 in ethyl alcohol; SSD-2, slides 04 and 09; same data; MZNA • 1 specimen; SSD-6, slide 08; same data; MZNA • 1 specimen; SSD-7, slide 08; same data; MZNA • 3 specimens; SSD-17, slide 04; same data; MZNA • 10 specimens; SSD-18, slides 03 and 04; same data; MZNA • 4 specimens; SSD-20, slide 05; same data; MZNA • 2 specimens on slide and 9 in ethyl alcohol; SSD-22, slide 03; same data; MZNA • 2 specimens; SSD-11, slide 13; same data; MZNA • 1 specimen; SSD-12, slide 09; same data; MZNA • 1 specimen; SSD-27, slide 04; same data; MZNA • 5 specimens; SSD-29, slide 08; same data; MZNA • 1 specimen; SSD-30, slide 05; same data; MZNA • 3 specimens; SSD-31, slides 11 and 14; same data; MZNA. REMARKS It had already been cited in the Sierra de Guadarrama by Cassagnau (1954). Originally described in Slovenia (East of Julian Alps, 2350 m) (Kos 1942), it has been cited in mountainous areas throughout Europe, excluding Great Britain, Norway, Sweden and Finland. Cited in Ireland, Russia (Urals, Caucasus) and Japan (Potapov 2001).

Published as part of Baquero, Enrique, Jordana, Rafael & Ortuño, Vicente M., 2021, Distinctive Collembola Communities in the Mesovoid Shallow Substratum: Entomobryomorpha of the Sierra de Guadarrama National Park (Central Spain), pp. 37-78 in Zoosystema 43 (3) on page 46, DOI: 10.5252/zoosystema2021v43a3, http://zenodo.org/record/4487162