Leptodinium dispertitum Cookson and Eisenack, 1965

Now Impagidinium. Originally Leptodinium, subsequently (and now) Impagidinium.

.Holotype: Cookson and Eisenack, 1965, pl.12, fig.5-6; Jan du Chêne et al., 1986, pl.149, figs.11-16
Paratype: Cookson and Eisenack, 1965
Locus typicus: SW Victoria, Australia
Stratum typicum: Late Eocene

Original description: Cookson and Eisenack 1965, p. 122-123
Description: Shell small, oval, without horn, tabulated, and divided equally by a relatively broad, helicoid girdle consisting of six plates. Plates smooth or faintly granular, bordered by transparent ledges. The longitudinal field on the ventral surface (representative of a longitudinal furrow), which extends from the apical plates to the antapical plate, is typically marked by three large plates; very occasionally the transverse wall between the two upper ones is incomplete. Archaeopyle formed by the removal of plate 3"". Tabulation: 3-4", 6"", 6g, 5""", 1p, 1"""".
Dimensions: holotype 62 Ám long, 57 Ám wide. Range 55-80 Ám long, 48-86 Ám wide.

Affinities:
Cookson and Eisenack, 1965. p. 123: L. dispertitum closely resembles L. maculatum Cookson and Eisenack, 1961 from Upper Eocene deposits in Rottnest Is., Western Australia. It is distinct from this species in that the surfaces of the plates are smooth or only faintly granular, not "distinctly notted" as in L. maculatum and the longitudinal field is usually divided, not continuous and furrow-like as in that species.