Hystrichodinium? amphiacanthum Cookson and Eisenack, 1958

Now Omatidium. Originally Hystrichodinium, subsequently Hystrichodinium?, thirdly (and now) Omatidium.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Hystrichodinium.

Holotype: Cookson and Eisenack, 1958, pl.5, fig.9
Locus typicus: Omati, Papua
Stratum typicum: Late Jurassic or Neocomian

Original description: Cookson and Eisenack, 1958, p. 37
This is a delicate form and most of the specimens are imperfectly preserved. The shell of the type is almost sphaerical and is provided with a narrow, faintly marked girdle and nine processes, four at one pole, five at the other. The processes are long and pointed, and widen towards the membrane. The membrane of the shell is delicate and no trace of surface markings remains. The main features of this species, i.e., the median girdle and the polar position of the processes, have been confined by less perfect paratypes.
Dimensions: Type 173 Ám overall, shell 52x71 Ám; processes 43-62 Ám long.