Achomosphaera communis, (Corradini, 1973, p.151, pl.22, figs.1a–b; pl.33, figs.1,3), Sarjeant, 1981, p. 122.

NOW Cordosphaeridium. Originally (and now) Cordosphaeridium, subsequently Achomosphaera. Lentin and Williams (1985, p.3) retained this species in Cordosphaeridium.

Holotype: Corradini, 1973, pl.22, figs.1a-b.
Age: Late Cretaceous.
Locus typicus: Viano, Reggio Emilia, Italy
Stratum typicum: Late Cretaceous-?Paleocene

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Original description as Cordosphaeridium commune: [Corradini, 1973, p. 151]:

Diagnosis:
Ovoidal central body with wall composed of thick, granulate endophragm, and thinner, slightly fibrous periphragm.
Processes solid, cylindrical to taeniate, with broad base and distal terminations aculeate.
Archeopyle precingular.

Description:
Chorate dinoflagellate cyst having a quite thick, granular endophragm (+/-2µm) and a more thin, slightly fibrous periphragm.
Processes solid, cylindrical taeniate with broad, fibrous base, having thickened ribs extending along their length until the apex. Distal margin terminating with a sort of a rosette of spines, sometimes bifid and arranged in a more or less regular pattern. Adjacent processes are occasionally united proximally by low ribs or crests. There are 28 to 32 processes, unequal in width but not strongly varying in length. The width of the processes is mostly unrelated to the position they occupy on the central body. Only the few sulcal processes are normally thin and lacking in distal rosette.
Precingular, well developed archeopyle with basal margin showing often medially a little cut corresponding to the connection zone of two cingular plates.

Dimensions:
Holotype: diameter of the central body 62x75 µm, length of the processes 30-38 µm.
Range: diameter of the central body 52-(63)-78 x 60-(73)-90 µm. length of the processes 20-(30)-50 µm.