Hystrichosphaeridium speciale Lentin and Williams, 1981, nom. subst. pro Hystrichosphaeridium? irregulare (Merrill, 1895) Sarjeant, 1964, non Hystrichosphaeridium irregulare Pocock, 1962

Originally Geodia? irregularis, subsequently Hystrichosphaeridium speciale. See also Hystrichosphaeridium irregulare (combination illegitimate).
Tax. jr. synonym of Xanthidium tubiferum var. complex (now Oligosphaeridium complex) White, 1842, according to Harker and Sarjeant in Harker et al., 1990.
Holotype: Merrill, 1895, text-fig.14
Age: Early Cretaceous