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

[Adnatosphaeridium buccinum, Hultberg, 1985c, p. 106, pl.1, figs.A-B.

Holotype: Hultberg, 1985c, pl.1, fig.A.]
Locus typicus: Limhamn area, southern Sweden
Age: Late Maastrichtian

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Original description: [Hultberg, 1985, p. 106]:

Description:
Chorate cyst, composed of autophragm only. The surface of the autophragm is smooth. The shape of the cyst is subspherical.
The paratabulation is expressed by intratabular processes. The processes are slender, hollow, or with a conical cavity in the proximal end. The process-tips are buccinate, and in some processes, expand to form a small, perforated platform. The processes are interconnected by trabeculae. The paratabulation is gonyaulacacean, paratabulation formula: 4', 6''', xc, lp, 6''', 1''''.
The archeopyle is apical, type tA. Operculum free.
Paracingulum is not discernible.
Parasulcus is clearly indicated by a perforated platform, interconnecting the processes corresponding to paraplates 6'', 6''', and 1-2'''.