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Xanthidium palmatum
Xanthidium palmatum (White, 1842) Bronn, 1848
Now Hystrichosphaeridium recurvatum. Originally Xanthidium tubiferum var. palmatum (a desmid varietas), subsequently Xanthidium palmatum, thirdly Spiniferites palmatus, fourthly Cordosphaeridium palmatum, fifthly Hystrichosphaeridium recurvatum; see also Hystrichosphaeridium palmatum (name illegitimate) and Hystrichosphaeridium duplum (name illegitimate). 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 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
Now Hystrichosphaeridium recurvatum. Originally Xanthidium tubiferum var. palmatum (a desmid varietas), subsequently Xanthidium palmatum, thirdly Spiniferites palmatus, fourthly Cordosphaeridium palmatum, fifthly Hystrichosphaeridium recurvatum; see also Hystrichosphaeridium palmatum (name illegitimate) and Hystrichosphaeridium duplum (name illegitimate). 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 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