Acrosphaera spinosa group?
Irregular pores and many irregularly arranged spines scattered about the surface, some of the latter extending from the pore-rims. Spine and pore patterns are variable. Shell diameter: 60 to >200 µm. Various authors attempted to group the different morphotypes within this taxon. (C. Polycystina (Spumellaria) 2).
Nigrini and Moore (1979) recognized 4 closely related species: Polysolenia aktios Nigrini, very similar to Acrosphaera spinosa but restricted to the Subarctic (103-238 µm); Polysolenia flammabunda (Haeckel), with somewhat larger pores and longer spines (81-136 µm); Polysolenia lappacea (Haeckel), spines curved and often interconnected (81-109 µm); and Polysolenia spinosa (Haeckel) (81-164 µm). Boltovskoy and Riedel (1980) recognized 3 formae (A, B and C) of this species in Southwestern Atlantic planktonic materials.
Ref.: Strelkov and Reshetnjak (1971), Boltovskoy and Riedel (1980).