From Fensome et al., 2019:
Homotryblium ssp. breviradiatum (Cookson and Eisenack, 1961b, p.44, pl.2, figs.10–11) Lentin and Williams, 1977b, p.75. Holotype: Cookson and Eisenack, 1961b, pl.2, figs.10–11. Originally Hystrichosphaeridium floripes subsp. breviradiatum, subsequently Cordosphaeridium floripes subsp. breviradiatum, thirdly (and now) Homotryblium floripes subsp. breviradiatum. Age: Late Eocene.

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