Ericiolus mattioliae 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 : 185

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

Figs 16–20

DESCRIPTION: Coccosphere shape unknown, possibly subspherical or saddle-shaped but found collapsed, and with 30–60 nannoliths. Nannoliths with three coplanar rays, equally positioned, with delicate bifurcations near their tips; the bifurcations are short and have short, upturned tips. On the distal side, laths extend vertically up from each ray, developing from the centre of the nannolith to about two-thirds of the length of the ray. The laths are slightly higher at the centre giving a curved profile, and are slightly thickened along their distal edge. On the proximal side of the nannolith, grooves run along the rays from the bifurcation to the centre of the nannolith, where they unite to form a small central pore ( Fig. 18 , upper arrow).

DIMENSIONS: Coccosphere diameter c. 4.5 μ m; nannoliths 0.6–1.3 μ m long and wide. Ray 0.4–0.6 μ m long. Laths 0.3–0.6 μ m long.

HOLOTYPE: Stub no. 704/2 deposited at the facilities of NHM, UK ( PM NF 5517 285–33). Specimen shown in Fig. 16 .

PARATYPE: Stub no. 704/2 deposited at NHM, UK ( PM NF 5517 285–31). Specimen shown in Fig. 17 .

TYPE LOCALITY: 32°10.74 ʹ S, 29°49.56 ʹ W, depth 72 m, 2 November 2008, AMT18 Cruise, Station CTD089 .

DISTRIBUTION: Subtropical low-photic waters.

NUMBER OF SPECIMENS STUDIED: 4.

ETYMOLOGY: After Professor Emanuela Mattioli (Université Claude Bernard Lyon 1) in recognition of her contributions to the field of Jurassic and Lower Cretaceous coccolithophore palaeoceanography.

REMARKS: The species differs in showing three coplanar rays with a small bifurcation occurring near the tips of the rays.In addition, the nannoliths bear delicate laths that form a calyx distally and they develop from the nannolith central spine towards the tips of the rays by becoming progressively shorter. The laths are also seen to develop along the nannolith rays, across their axis.

Figures

Figs 16–20. SEM micrographs of Ericiolus mattioliae sp. nov. Scale bars = 1 μm. Fig. 16. Holotype. Coccosphere with star-shaped nannoliths showing three rays with small bifurcation at their tips (arrows). Fig. 17. Paratype. Coccosphere with nannoliths showing, in distal view, delicate laths that develop from approximately one-quarter from the tip of the ray (arrow; side view) towards the nannolith centre, vertically up. Fig. 18. Detailed view of star-shaped nannoliths of the specimen shown in Fig. 17. Proximal nannolith side with a central pore made by axial grooves (upper arrow); distal nannolith side showing a star-shaped calyx reaching approximately one-quarter of the tip of the ray (lower arrow). Fig. 19. Collapsed individual nannoliths with bifurcation at the tip of the rays. Arrow indicates the lath-made calyx in side view. Fig. 20. Collapsed coccosphere specimen. Nannoliths bearing delicate laths that become progressively higher towards the nannolith centre, forming a calyx. The elements of the calyx appear blockier at its distal end (arrow).