Exochosphaeridium striolatum subsp. truncatum

"subsp. truncatum" (Davey, 1969a, p.164-166, pl.7, figs.1-3) Lentin and Williams, 1973, p.56.  Emendations: Masure, 1988b, p.129 and Harker and Sarjeant in Harker et al., 1990, p.73-74, both as Pervosphaeridium truncatum.  Holotype: Davey, 1969a, pl.7, fig.2; Masure, 1988b, pl.4, figs.6A-B; text-fig.5, nos.1-2.  NOW Pervosphaeridium truncatum.  Originally Exochosphaeridium striolatum var. truncatum, subsequently Exochosphaeridium striolatum subsp. truncatum, thirdly Exochosphaeridium? truncatum, fourthly (and now) Pervosphaeridium truncatum.  Age: Cenomanian. Parent: Exochosphaeridium striolatum