Syracosphaera lafourcadii ( Lecal 1967 ) Archontikis, Young, Cros, 2020

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, pp. 121-139 : 129

Species Syracosphaera lafourcadii ( Lecal 1967) Archontikis, Young, Cros comb. nov. HOL

Basionym: Helladosphaera (Cyclohelladosphaera) lafourcadii Lecal 1967 Hydrobiologia vol. 29, pp. 326– 328, text-figs. 21, 22, figs. 28–30.

Synonymy: Anthosphaera lafourcadii (Lecal) Kleijne (1991) , p. 41, Pl.7 IX, Figs. 1–2 ; Winter and Siesser (1994), p. 148, Fig. 165; Aubry (1999), p. 247, Fig. 5; Cros (2001), p. 80, Pl. 55, Figs. 5–6; Cros and Fortuño (2002), p. 148, Fig. 86D; Young et al. (2003), p. 90, Pl. 42, Fig. 2 ; Dimiza (2006), p. 82, Pl. XXVI, Fig. 4 ; Malinverno et al. (2008), p. 137, Fig. 109.

Description: Coccosphere, spherical in shape, with c. 60–70 BCs and c. 10 CFCs. BCs consist of an ellipti- cal, narrow rim that is tightly connected to a vaulted central structure, made delicately of less regular crys- tallites. Several struts of one or two crystals width connect the dome-like distal cover with the rim, leaving pores in the perforate cycle, consistently present. No apical boss can be observed on top of the BCs’ central distal cover. CFCs possess a broad but low (height similar to width) leaf-like process, with a large arched opening.

Remarks: BCs are similar to those of S. molischii var. molischii HOL , but smaller and with noticeably less regular crystallites. The CFCs are distinctively dif- ferent, having a well-formed arch and lacking the large leaf-like extension.

Dimensions: Coccosphere diameter c. 4–5 μm. BCs c. 0.8 μm long x 0.6 μm wide. CFCs’ distal process c. 0.8 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.

Fig. 1. Map of the sampling locations, where Anthosphaera was observed.

Fig. 2. Schematic representation and terminology of Anthosphaera coccosphere and holococcolith types.