Ericiolus bendifii Archontikis, J.G. Millán, A. Winter & Jer. R. Young, 2023

Archontikis, Odysseas A., Millán, Josué G., Winter, Amos & Young, Jeremy R., 2023, Taxonomic re-evaluation of Ericiolus and Mercedesia (Prymnesiophyceae) and description of three new species, Phycologia 62 (2), pp. 179-193 : 184-185

Ericiolus bendifii Archontikis, J.G. Millán, A. Winter & Jer. R. Young sp. nov.

Figs 8–15

SYNONYMY: Ericiolus ? sp. sensu Young et al. (2003, p. 85, pl. 39, fig. 14).

DESCRIPTION: Coccosphere shape unknown, possibly subspherical or saddle-shaped but found collapsed. It consists of c. 50–70 triradiate, star-shaped nannoliths probably forming a single-layered cover. Nannoliths with three coplanar bifurcate rays. The rays are symmetrically arranged (120° angle between them) and bifurcate near the centre of the nannolith with the bifurcations directed radially. The bifurcations are parallel-sided, and tips of each bifurcation are directed distally. On the distal side of the nannolith, there is an elongate central spine with a robust terminal knob. On the proximal side of the nannolith, axial grooves run along the rays from the bifurcations to the centre where they meet to form a small central pore ( Fig. 12 ).

DIMENSIONS: Coccosphere diameter 2.5–4.5 μ m; nannoliths 0.3–0.6 μ m long and wide. Ray 0.1–0.3 μ m long.

HOLOTYPE: Stub no. 302/2 deposited at the facilities of NHM, UK ( PM NF 4663 193–64). Specimen shown in Fig. 8 .

PARATYPE: Stub no. 459/2 deposited at NHM, UK ( PM NF 4814 275–53). Specimen shown in Fig. 9 .

TYPE LOCALITY: North-western Mediterranean and Alboran Seas (37° 25.8 ʹ N, 0°25.3 ʹ W, depth 42.5 m ( DCM), October 1999, MATER-II Cruise, Station 69–11).

DISTRIBUTION: Subtropical low-photic waters.

NUMBER OF SPECIMENS STUDIED: 16.

ETYMOLOGY: After Professor El Mahdi Bendif (Institut des Sciences de la Mer de Rimouski), in recognition of his contributions to the field of extant coccolithophore genetics.

REMARKS: Young et al. (2003) previously reported the holotype when examining plankton assemblages of Mediterranean waters and identified via SEM the possession of bifurcate rays in its nannoliths. The authors argued that this specimen (their p. 85, pl. 39, fig. 14, labelled as ‘ Ericiolus ? sp.’) was reminiscent of Ericiolus , and although its morphology was incompatible with the generic description, the form probably represented a closely related taxon. This is now confirmed via our morphologic and biometric findings and therefore, it is established as a discrete morphospecies. The species differs in possessing nannoliths with three bifurcated rays, vertically directed ray-tips and an elongate central spine with a terminal knob. The bifurcation occurs near the nannolith centre.

Figures

Figs 8–15. SEM micrographs of Ericiolus bendifii sp. nov. Scale bars = 1 μm. Fig. 8. Holotype. Coccosphere with star-shaped nannoliths showing three bifurcate rays and a central spine (arrow) with a robust terminal knob on distal side. Fig. 9. Paratype. Central spine with a terminal knob at the centre of the nannolith and ray tips deflected upwards (arrow). Fig. 10. Collapsed monomorphic coccosphere with star-shaped nannoliths. Fig. 11. Nannoliths with three coplanar rays showing bifurcation near their centre (arrow). Fig. 12. Detail of star-shaped nannoliths in proximal view showing a central pore (arrow) made by axial grooves that run along the rays. Fig. 13. Collapsed coccosphere showing nannoliths with a central spine that is oriented outward. Fig. 14. Collapsed coccosphere; the nannoliths surrounding the coccosphere show their central spine outward (arrow). Fig. 15. Detailed view of an individual nannolith showing a long (arrow) central spine that terminates in a prominent knob.