Nannotax Enabling nannofossil research

Description: Coccospheres artichoke-like, formed of numerous plate-like, slightly curved, nannoliths. The nannoliths are single calcite crystals with c-axis parallel to the length.

Remarks: Typically the nannoliths are slightly tapered and terminated at the broader end by a pair of crystal faces. They are easily overlooked in the light microscope butcan be reliably identified and have yielded very strong palaeoceanographic signals in Quaternary sediments. They are also readily obserarvable in well-peserved Pliocene and Late Miocene sediments, with unambiguous occurrence at least to NN10 and less certainly to NN5.

Ecology: Florisphaera profunda is an exclusively deep-photic species, usually occurring below the deep-chlorophyll maximum and is most abudant below oligotrophic surface waters. It occurs in sediments at much higher abundances than classic surface oligotrophic taxa such Umbellosphaera or Discosphaera and so is more reliable as an indicator of surface water oligotrophy.

Florisphaera is abundant in modern deep photic communities and is believed to be an Haptophyte but its precise affinities are uncertain. The coccospheres are artichoke-like with individual liths formed of single calcite crystals. Very abundant in well preserved Neogene open-ocean sediments, but easily overlooked and so rarely recorded. Monospecific.

Range: NN5? to 21.

Varieties: Modern F. profunda is rather variable, there are three formally described varieties, and several undescribed forms so it may in fact be a plexus of several species. See Quinn et al. (2005) for a longer review and much new data:

• Florisphaera profunda var. profunda Okada and McIntyre, 1980 - liths ending with straight of zig-zag edge.
• Florisphaera profunda var. elongata Okada and McIntyre, 1980 - liths more elongate, ending in an obtuse angle.
• Florisphaera profunda var. rhinocera Quinn et al. 2005 - liths ending straight edge with spine formed from ridge along dextral (right hand) side.