Syracosphaera periperforata (Kleijne) 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 (3 - 4), pp. 121-139 : 132

Species Syracosphaera periperforata (Kleijne) Archontikis, Young, Cros comb. nov. HOL

Basionym: Anthosphaera periperforata Kleijne 1991 Mar. Micropaleontol , vol. 17, p. 41, Plate IX, Figs. 3–4 non Figs. 5–6.

The species S. periperforata HOL is characterised by body-coccoliths, with a prominent perforate cy- cle. The perforations are elongate and typically show consistent anticlockwise obliquity in distal view. The central structure may be domal or conical. The circum-flagellar coccoliths have similarly constructed rims, with medium-sized arched processes (c. 1.0–1.5 μm long). It is an unusual taxon among extant holococcolithophores in showing strong chirality; if the perfora- tions are oblique, they are always directed anticlock- wise in distal view. The species is morphologically variable ( Cros and Fortuño 2002; our observations) in that 1) body-coccoliths and antapical coccoliths may or may not possess an apical boss on top of their central distal cover, 2) the central structure may be conical or dome-shaped, 3) the perforate cycle is variably de- veloped, and 4) circum-flagellar coccoliths may show a flat or a pointed top. If these characters are considered together, then they define a limited number of recurring morphotypes, and we believe these should be regarded as discrete taxa. One of the forms appears sufficiently well-separated to be treated as a distinct species, how- ever, for the other three, the evidence is less clear and therefore, we describe them as varieties.

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.