Dapcodinium wapellense (Pocock, 1972) emend. D÷rh÷fer and Davies, 1980

Now Opaeopsomus. Originally (and now) Opaeopsomus, subsequently Dapcodinium, thirdly Valvaeodinium.
Lentin and Williams, 1981, retained this species in Opaeopsomus Pocock, 1972.
Holotype: Pocock, 1972, pl.24, fig.14
Locus typicus: Western Canada
Stratum typicum: Callovian

Original descrpition: Pocock, 1972, p.97: Opaeopsomus wappellensis
Vesicle ellipsoidal to sphaerical; epitheca and hypotheca hemipshaerical; no apical or antapical processes developed; transverse furrow well delineated; parallel sided; helicoidal, 6 Ám wide, longitudinal furrow only faintly visible over part of its lengh. archaeopyle apical with free simple operculum; vesicle two-layered, casule smooth; about 5 Ám thick; tightly appressed to outer layer; sutures reflected by narrow raised ridges, 4 Ám high and less than 0.25 Ám wide; accessory ridges developed in addition to the sutural ridges; making determination of tabulation impossible; brocci of reticulum resulting from intersection of ridges, rounded and very variable in size; 1.0x5.0 Ám wide; thin membrane developed completely enveloping the vesicle and supported by the ridges; colorless to pale yellow; size range 42.9-45.0x39.6-43 Ám.

Emended diagnosis: D÷rh÷fer and Davies, 1980
Proximate dinoflagellate cysts with circular ambitus and slight apical horn. Tabulation expressed by sutural crests, surface otherwise smooth. Tabulation 4", 5a, 7", 7c, 7""", 4p, 1"""", 5s. Disintegration archeopyle, 4A + 5l + 7P initiating at 2a.

Affinities:
Pocock, 1972, p.97: Differs from Fovilarnax in posessing transverse and longitudinal furrows, thus indicating definite dinoflagellate affinity.