Heliodiscus bipolaris, Dumitrica, 2019

Dumitrica, Paulian, 2019, Cenozoic Spumellarian Radiolaria With Eccentric Microsphere, Acta Palaeontologica Romaniae 15 (1), pp. 39-60 : 52

Heliodiscus bipolaris n. sp

Figures 8d, e, h

Description. Medullary test double, prunoid with an eccentric microsphere. Cortical shell ovoid in face view and lenticular in side view, the broader part at the end where the microsphere is closer to the outer medullary shell. The two ends of cortical shell with a bunch of numerous irregular and short spines. No opening visible at these ends.

Material. A single specimen in DSDP 21-206-29 CC.

Holotype. The illustrated specimen, coll. MGL 103560 .

Dimensions. Diameter of microsphere 14 μm, of outer medullary shell 40-50 μm, length of cortical shell 135 μm, breadth of cortical shell shell 102 μm.

Etymology. Having two poles.

Remarks. This species differs from the other species of the genus by not having a circular outline but en elliptical one in face view and peripheral spines only at the two ends of the cortical shell.

Range and occurrence. Late Miocene, New Caledonia Basin, DSDP 21-206-29 CC.

Figures

Fig. 8 a, c - Excentrococcus annulatus Dumitrică; a – mature specimen, face view, DSDP 21-205-7-1, 70-72 cm, scale bar 100 μm; c – other specimen, transversal section along the longitudinal axis showing the eccentric microsphere, DSDP 21-206-29CC, scale bar = 100 μm. b, f, g - Heliodiscus riedeli nov. sp., PROA 96P. d, e, h – Heliodiscus bipolaris nov. sp. focused at centre, on surface, and in lateral view, respectively, scale bar = 50 μm, DSDP 21-206-29CC.