Syracosphaera periperforata var. cylindrata 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 : 134

Syracosphaera periperforata var. cylindrata Archontikis, Young, Cros var. nov. HOL

Synonymy: Anthosphaera periperforata Kleijne 1991, p. 41 , Pl. IX, Figs. 5–6; Aubry (1999), p. 248, Fig. 6 (lower panel).

Anthosphaera periperforata type 1 Cros (2001), p. 81, Pl. 56, Figs. 1–2 ; Cros and Fortuño (2002), p. 59, Figs. 87A, 87C; Young et al. (2003), p. 90, Pl. 42, Fig. 5.

Derivatio nominis: From Latin cylindratus –a –um (adjective), cylindrical; referring to the somewhat cylindrical structure of the BCs.

Description: Coccosphere, usually spherical, composed of c. 40–80 BCs and c. 7–14 CFCs. BCs elliptical, rim one crystallite wide and loosely connected to a short cylinder-like distal cover at the central structure via c. 15–20 short, delicate connecting struts of crystal elements. The walls of the cylindrical structure are formed of compacted struts of crystallites, the top is nearly flat and typically without any central apical boss; however, some antapical coccoliths may bear a weak apical boss. CFCs with broad arch, supported by two short but robust columns, often with a central apical spine.

Remarks: The cylindrical form of the protrusion combined with the absence of a central apical boss readily separates the BCs of S. periperforata var. cylindrata . The CFCs are less distinctive, but generally less ornamented than those of other varieties.

Dimensions: Coccosphere diameter is c. 6 μm. BCs c. 1.0 μm long x c. 0.7 μm wide. CFCs c. 1.0 μm long and wide; CFCs’ distal process 1.0 μm high.

Holotype: Negative nº 140501 ( Plate 4 , Fig. 3 ), curated at the ICM (CSIC), Barcelona, Spain.

Paratype: Specimen illustrated at Plate 4 , Fig. 4 .

Type locality: Station Meso-96 E3/4, 40m water depth, collected from the NW Mediterranean Sea (41º23.0N 3º10.2E), cruise Meso-96, 1 July 1996.

Number of specimens studied: 7

Distribution: Sub-tropical waters

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.

Plate 4. Syracosphaera periperforata (Kleijne) Archontikis, Young, Cros comb. nov. HOL Scale bars = 1μm

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

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