Pulvinosphaeridium oligospinosum (Eisenack, 1934 ex Eisenack, 1938) Eisenack, 1954

Now Estiastra? oligospinosa (an acritarch species). Originally Hystrichosphaeridium oligospinosum, subsequently Pulvinosphaeridium oligospinosum, thirdly Veryhachium oligospinosum (an acritarch species), fourthly Goniosphaeridium oligospinosum (an acritarch species), fifthly (and now) Estiastra? oligospinosa (an acritarch species); see also Ovum hispidum ssp. oligospinosum (name not validly published).
Holotype: Eisenack, 1934, pl.4, fig.18; lost, according to Eisenack et al., 1973
Age: Silurian (based on material from an erratic)