From Williams, Lentin and Fensome 1998 - Lentin and Williams Index of Fossil Dinoflagellates:

[Achomosphaera reticulata, Clarke and Verdier, 1967, p. 41-42, pl.8, figs.2-3; text-fig.16.

Holotype: Clarke and Verdier, 1967, pl.8, fig.2]
Locus typicus: Isle of Wight, England
Age: Cenomanian-Santonian

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Original description: [Clarke and Verdier, 1967, p. 42]:

Diagnosis:
Body reticulate, processes solid.

Description:
Outline of body circular. Wall up to 3 microns thick. Sculpture of body reticulate, uniformally distributed. Muri thin, luminae rounded or polygonal. Numerous processes arise from the body without obvious symmetry. These are long, being approximately half the body diameter in length, solid or with a narrow canal which terminates at the point of division distally. The initial division is a bifurcation or trifurcation becoming polyfid towards the distal extremity. The processes are smooth except for a general encroachment of the body sculpture proximally.
A precingular archaeopyle is an obvious feature of most specimens; other than this the specimens show no obvious orientation.

Dimensions:
Measurements: Holotype Range
Diameter of body 48 µm 38-53 µm
Length of processes 21-26 µm 15-28 µm

Affinities:
A. reticulata differs from the type species in the sculpture of the main body.