H. wallichii coccosphere, scale bar 1 micron

Description:

Helicosphaera wallichii (Lohmann 1902) Okada & McIntyre 1977 [Coccolithophora] Like H. carteri but: central-area with oblique twisted slits; bridge typically better developed; and liths perhaps slightly larger.  NB Slits obliquity: In distal view the slits are rotated about 10-20° clockwise (and so away from the wing), this is the “normal” sense of obliquity in Helicosphaera, as shown by many fossil species. The Pleistocene species H. inversa is similar but shows the opposite sense of obliquity. HOL phase - unknown but H. wallichii often co-occurs with Syracolithus dalmaticus in our samples (Geisen et al., 2004).