Syracosphaera marginiporata Knappertsbusch 1993

Archontikis, Odysseas A., Young, Jeremy R. & Cros, Lluïsa, 2020, Taxonomic Revision and Classification of Extant Holococcolithophores Previously Placed in the Genus Anthosphaera Kamptner emend. Kleijne 1991, Acta Protozoologica 59 (3 - 4), pp. 121-139 : 129

Species Syracosphaera marginiporata Knappertsbusch 1993 HOL

Synonymy: Anthosphaera sp. type B Cros and For- tuño (2002), p. 60, Figs. 88B, 112C–112D; Percopo et al. (2011), p. 256, Fig. 30.

Syracosphaera marginiporata HOL Šupraha et al. (2018) , p. 27, Fig. 4c .

Description: Coccosphere, spherical but usually seen collapsed, with c. 80–140 tiny BCs and c. 5–10 CFCs. BCs elliptical, with a single-crystallite-width rim and a rounded central structure, formed from sev- eral, usually large, angular crystals typically with open- ings in between. The rim appears separated from the central structure, i.e. there is a gap, where the perforate cycle would be. CFCs with a large central arch attached to the rim by robust lateral columns of large crystallites; vertical process extends as a large thin leaf with rounded to somewhat straight sides that are constructed by small crystallites arranged in characteristically ordered disposition.

Remarks: BCs’ central structure is made by a few crystallites; it is perforated and bears no apical boss or any other structure on top. The perforate cycle does not possess any crystallites. The central structure is not attached to the rim by any visible calcification, but both the rim and the distal cover are supported by an organic baseplate.

Dimensions: Coccosphere diameter c. 4 μm. BCs c. 0.6 μm long x 0.4 μm wide. CFCs’ distal process is c. 1 μm high.

Figures

Plate 3. Scale bars = 1μm 1–2. Syracosphaera lafourcadii (Lecal) Archontikis, Young, Cros comb. nov. HOL Complete coccospheres composed of CFCs that bear low distal processes (see arrows) and BCs with distal covers made of irregularly ar- ranged crystallites. 3–4. Syracosphaera origami (Cros and McGrane) Archontikis, Young, Cros comb. nov. HOL Coccospheres with highly ornamented CFCs showing triangle-shaped distal processes (fig. 3, arrow) and BCs with an organic base-plate in proximal view (fig. 4, arrow a) and a rim that supports delicate struts of crystallites holding the origami-like paper boat distal covers (fig. 4, arrow b) in distal view.