Aylostera iscayachensis was described (as Rebutia (Digitorebutia) iscayachensis) in Succulenta 56, p. 3, by Walter Rausch in 1977.

Here is the text of the description in Latin, as published, with my own English translation below. You should look up the original description for more details, drawings and photographs.

Rebutia (Digitorebutia) iscayachensis Rausch spec. nova

Simplex, globosa ad brevicylindrica, radice rapiformi carnosa, 20 mm diametens, atroviridis et valde fusco-violaceo-asperata; costis 11, recte adscendentibus vel paululum tortis, crenis transversis in gibberes ca. 4 mm longos et latos divisis; areolis ovalibus,, 2-3 mm longis, clare-fusco-tomentosis; aculeis marginalibus 8-9 accumbentibus, 2-3 mm longis, flavidis, basi incrassata fuscis; aculeo centrali O. Floribus 35 mm longis et diametientibus; ovario roseo, receptaculo viridulo, squamis fuscis, pilis et setis albis tecto; phyllis perigonii exterioribus lanceolatis, violaceo-roseis, medio-viridi-striatis; phyllis perigonii interioribus spathulate-rotundis, rubris et intus violaceo-roseis; fauce violaceo-rosea, filamentis violaceis, stylo viridi, 22 mm longo, 6 mm eius cum receptaculo connato, stigmatibus 8 viridibus. Fructu et seminibus Rebutiae pygmaeae (Fries) Br. et R. modo. Patria: Bolivia, apud Iscayachi, 3.500 m alt.

Typus: Rausch 335 B, depositus in Herbario Collectionis Plantarum Succulentarum Municipali Turicensi, Helvetia.

English translation

Rebutia (Digitorebutia) iscayachensis Rausch spec. nova

Unbranched, spherical to short cylindrical, with fleshy tuberous roots; 20 mm in diameter, epidermis dark green and strongly flushed with brownish purple; ribs 11, straight or slightly twisted, divided by transverse notches into ± 4 mm long and broad tubercles. Areoles oval, 2-3 mm long, with light brown felt; marginal spines 8-9, lying flat, 2-3 mm long, yellowish with thickened, brown base. No central spine.

Flower 35 mm long and in diameter; ovary pink and flower tube greenish with dark brown scales, white hairs and bristles; outer petals lanceolate, purple-pink with green central stripe; inner petals spatulate-round, red and purplish-pink inside; throat purplish pink. Purple stamens, green pistil 22 mm long, 6 mm of which fused with the flower tube; stigmas 8, green. Fruit and seed as Rebutia pygmaea (Frisian) Br. & R.

Habitat: Bolivia, near Iscayachi at 3500 m.

Type Rausch 335 B, deposited in the Herbarium of the Municipal Succulent Plant Collection in Zurich, Switzerland.