Diagnosis.—Small, subcircular to ovoid to arrowhead-shaped, convex mounds (hyporelief ) or concave pits (epirelief ), usually with medial keel; occurring in small to large groups; medial keel may or may not be present (Häntzschel, 1975; Głuszek, 1995; Garvey & Hasiotis, 2008).