Hystrichosphaeridium diktyoplokus ssp. latum Klumpp, 1953; Emendation: Sarjeant, 1981, p.106-107, as Plethysyrinx lata - however, see Lentin and Williams (1985, p.72).

Now Cordosphaeridium latum. Originally Hystrichosphaeridium diktyoplokus ssp. Iatum, subsequently Cordosphaeridium diktyoplokus ssp. Iatum, thirdly Areosphaeridium diktyoplokus ssp. Iatum, fourthly Plethysyrinx lata, fifthly (and now) Cordosphaeridium latum.

Holotype: Klumpp, 1953, pl.18, figs.8-9
Age: Eocene