Resumen:
Simple Summary The material for this study was obtained after intensive sampling in the colluvial mesovoid shallow substratum (MSS) of the Sierra de Guadarrama National Park using 33 subterranean sampling devices (SSD). The data were obtained from the first extraction of the traps between May and October of 2015. This paper presents the results for a small part of the total Collembola captured (4.4% of the total for this sampling), namely, the Neelipleona and Symphypleona. Eleven species belonging to seven families were identified, two of which are new species. Based on the results of this study, and others previously published on Collembola of the MSS in the Sierra de Guadarrama National Park, the presence of epigeal and edaphic species is observed, which, in general, are not as abundant as the newly discovered species. The high abundance and extensive presence in the hypogean environment of most of the new species discovered are indicative that the MSS has a unique and distinct Collembola community. Megalothorax minimus (Neelidae) and Sphaeridia pumilis (Sminthurididae) had already been identified in surface sampling from Sierra de Guadarrama. In Europe, Sminthurinus gisini (Katiannidae) seems to be associated with environments at specific altitudes, and has little representation in this sampling. Pygmarrhopalites custodum Baquero and Jordana sp. nov. (Arrhopalitidae) coexists with two previously identified surface occurring species of the same family (P. elegans and Arrhop
