radiolaria - rads_cenozoic - Joergensenium clevei radiolaria - rads_cenozoic - Joergensenium clevei

Joergensenium clevei

Classification: rads_cenozoic -> Actinommidae -> Quinquecapsulariidae -> Joergensenium -> Joergensenium clevei
Sister taxa: J. arcticum, J. clevei, J. rotatile, J. sp.


Citation: Joergensenium clevei Dumitrica&Bjørklund, in Ikenoue et al. 2016
taxonomic rank: species
Basionym: Joergensenium clevei Dumitrica and Bjørklund, in Ikenoue et al. 2016
2016 Joergensenium clevei - Ikenoue et al Text-figure 2.3; Plate 7

Catalog entries: Joergensenium clevei

Original description: Description: Test as with the genus, consisting of 3 concentric shells of which one is cortical and two medullary. Cortical shell thin-walled, spherical with numerous polygonal (usually pentagonal or hexagonal) pores arranged irregularly and of relatively equal size (Pl. 7, Figs 1a, 2a). It is covered by numerous small by-spines originating not in the vertices of the pore frames but on the intervening bars of the frames (Pl. 7, Fig. 1). Sometimes, and on some portions, they can be interconnected by very thin bars. Microsphere has a shape of a short pentagonal prism with one lateral edge simple and straight or slightly curved, representing the MB, and the other four curved and provided with an additional radial bar (ad) in their middle. All corners represent points of origin of 10 rays, of which 2, at the ends of MB, are apical (A), 4 are basal (B), and the other 4 are antapical (ant), refer to Text-Fig. 2.3. At the level of the second medullary shell, all these rays are interconnected by arches forming a second prismatic shell with curved edges that repeats the fundamental shape of the microsphere. Second medullary shell has 7 cupolas erected on these edges (some cupolas are seen in Pl. 7, Figs 1b, 2c-e) and corresponding to the 7 facets of the polygonal prism. Cupolas are well marked especially in axial view, which is the view along the MB. All the 14 rays originate in the microsphere periphery in the arches of the second medullary shell, and only occasionally1-2 rays may be prolonged as thin rays up to the cortical shell. The tops of the 7 cupolas are at the origin of 7, three-bladed radial bars that traverse the cortical shell and extend outside it into pointed spines that usually are not longer than their inner portion.


Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source:
First occurrence (base): within Recent modern (0.00-0.00Ma, base in "Holocene" stage). Data source:

Plot of occurrence data:


Ikenoue, T., Bjørklund, K. R., Dumitrica, P., Krabberoed, A. K. & Kimoto, K. (2016). Two new living Entactinaria (Radiolaria) species from the Arctic province: Joergensenium arcticum n. sp. and Joergensium clevei n. sp. Marine Micropaleontology. 124: 75-94. gs


Joergensenium clevei compiled by the radiolaria@mikrotax project team viewed: 17-7-2024

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