Ecology: Puna; on exposed rock. Elevation: ca. 4000 m. Distribution: Endemic to the tropical Andes (Peru).

Ecología: Puna; sobre rocas expuestas. Elevación: 4000 m de elevación. Distribución: Endémica para Perú. Sólo conocida de la localidad tipo (Perú)..

Zygodon petrophilus is characterized by tomentose stems 3-4 cm, imbrícate and somewhat 5-ranked leaves that are squarrose recurved when dry, ovate-lanceolate,  to 2 mm, few irregular teeth near apex, subpercurrent costa with distal 3/4 back roughened, distal 2/3 densely papillose cells, basal 1/3 with smooth cells, seta 5-6 mm, straight to slightly curved, 5-ribbed capsules to 2 mm, double peristome, pale, papillose 16 paired teeth exostome, endostome of 8 slender papillose segments (sometimes longer than exostome).