Xanthidium tubiferum var. palmatum White, 1842

Now Hystrichosphaeridium recurvatum. Originally Xanthidium tubiferum var. palmatum, subsequently Xanthidium palmatum (a desmid species), thirdly
Spiniferites palmatus, fourthly Cordosphaeridium palmatum, fifthly Hystrichosphaeridium palmatum (name illegitimate), sixthly Hystrichosphaeridium duplum.
Nomenclatural synonym of Xanthidium tubiferum var. palmaforme White, 1842 and Xanthidium tubiferum var. recurvatum White, 1842, which have the same holotype. Bronn, 1848, Sarjeant, 1964 and Stover and Evitt, 1978 regarded Xanthidium tubiferum var. palmatum (as Xanthidium palmatum) as the sr. synonym. However, when Downie and Sarjeant, 1965 transferred this species to Hystrichosphaeridium
Deflandre, 1937 they created a jr. homonym of Hystrichosphaeridium palmatum Deflandre and Courteville, 1939. Accordingly, Lentin and Williams, 1989 proposed the name Hystrichosphaeridium duplum as a nomen substitutum for Hystrichosphaeridium palmatum (White, 1842) Downie and Sarjeant, 1965. By doing this Lentin and Williams, 1989 created a nomenclatural jr. synonym of Xanthidium tubiferum var. recurvatum White, 1842, which has priority.
Holotype: White, 1842, pl.4, fig.12
Age: Senonian