Pappomonas flabellifera Manton and Oates 1975 emend. Thomsen and Østergaard

Thomsen, Helge A. & Østergaard, Jette B., 2014, Coccolithophorids in Polar Waters: Pappomonas spp. Revisited, Acta Protozoologica 53 (3), pp. 235-256 : 239-241

Pappomonas flabellifera Manton and Oates 1975 emend. Thomsen and Østergaard

Protoplast ca. 6 × 4 µm, with flagella up to 20 µm and a haptonema up to 8 µm long. The cell surface covered with oval calcified plates, 0.75 ± 0.07 × 0.46 ± 0.05 µm; the rims composed of 15–20 spade­shaped segments bluntly pointed distally and

1) Manton and Oates 1975 8) Espeland and Throndsen 1986 14) Ikävalko and Thomsen 1997

2) Manton and Sutherland 1975 9) Hansen et al. 1988 15) Ikävalko 1998

3) Manton et al. 1976a 10) Thomsen et al. 1988 16) Thomsen and Buck 1998

4) Thomsen and Oates 1978 11) Vørs 1992 17) Findlay and Giraudeau 2000

5) Thomsen 1979 12) Østergaard 1993 18) This publication

6) Thomsen 1981 13) Clausen et al. 1994 19) Thomsen unpublished

7) Christensen et al. 1985

ca. 0.1 µm high, separated at the base by narrow rod­shaped to triangular spacers; the plate surface a mosaic of elongated elements, with their long dimension parallel to the long sides of the oval except at the ends where the outermost bars continue to follow the line of the plate edg e. The number of lines of elements that can be counted along the short axis of a body coccolith is dependent on the overall size of the coccolith and varies from 3–6 with 3 being the most commonly observed number. At the flagellar pole of the cell, up to 15 conspicuous calcified appendages crowded together, each composed of a straight shaft ca. 1.0 µm long attached proximally to the surface of an oval base plate, marginally smaller than the ordinary oval plates but structurally similar, albeit with a less compact rim. Each appendage ends distally in an almost completely flattened fan­like blade ca. 1 µm long and up to 1.5 µm wide, in outline approximating to an inverted triangle with a point of 90° or less attached to the top of the shaft; the blade typically consists of two asymmetrically sized elements; the overlap between the shaft and the blade is short; the contour of the distal edge of the triangle variable but a central cleft always present; a few similar but smaller appendages, sometimes almost sessile on their base plates, scattered elsewhere on the cell.

Additional material of P. flabellifera from non-polar regions has been included here to help elucidate global morphological variability and the possible existence of morphological clusters that correlate with geographic realms. It is thus evident that cells collected off California ( Figs 15–17) are much similar to the South African type material when comparing e.g. details of the circumflagellar coccoliths (triangles with a simple median cleft separating two blades with a fairly simple geometry), whereas cells from Mexico ( Figs 13– 14) are almost mirror images of other South African cells ( Manton and Oates 1975, loc.cit. Fig. 13) characterized by carrying – with reference to cell dimensions at large – exceptionally prominent circumflagellar coccoliths with very pronounced lateral extensions on each blade. The Californian and Mexican cells are additionally characterized by encompassing body coccoliths carrying a simplified and almost sessile central process. These coccoliths tend to be most abundantly present in particular towards the antapical end of the cell. This feature was also recognized in material from South Africa and it is obvious that the morphology of the reduced appendages is indeed very similar. While realizing the scarcity of material available there is at least an indication of a possible minor morphological separation between a ‘warm’ water contingent of P. flabellifera (S. Africa, California, Mexico) and a ‘cold’ water Northern Hemisphere contingent.

Thomsen et al. (1991) provided evidence for a shared life history among species of Pappomonas and species of Trigonaspis Thomsen 1980a . The combination cell illustrated (loc.cit. Fig. 17) involved P. borealis and T. diskoensis Thomsen 1980a and further examples of this specific partnership are added here (see below). It is worth emphasizing that a combination cell involving P. flabellifera has not yet been found. However, the likely candidate based on biogeographical evidence, is T. minutissima Thomsen 1980a .

The currently known biogeographical range of P. flabellifera is summarized in Table 2.