Xanthidium complex (White, 1842) Bronn, 1848

Now Oligosphaeridium complex. Originally Xanthidium tubiferum var. complex (a desmid varietas), subsequently Xanthidium complex, thirdly Hystrichosphaeridium complex, fourthly (and now) Oligosphaeridium complex.
Tax. sr. synonym of Hystrichosphaeridium elegantulum Lejeune-Carpentier, 1940, according to Deflandre, 1946.
Tax. sr. synonym of Hystrichosphaeridium himalayense Mehrotra and Sinha, 1981, according to Jain and Garg, 1986.
Tax. sr. synonym of Oligosphaeridium cephalum Sah et al., 1970, according to Lejeune-Carpentier and Sarjeant, 1981 and Jain, 1981.
Holotype: White, 1842, pl.4, fig.11; lost, according to Davey and Williams, 1966
Neotype: Davey and Williams, 1966, pl.7, fig.1; designated by Davey and Williams, 1966
Age: Senonian