radiolaria - rads_cenozoic - Astrophacus inca

Astrophacus inca

Classification: rads_cenozoic -> Heliodiscidae -> Astrophacus -> Astrophacus inca
Sister taxa: A. inca, A. linckiaformis, A. sp.


Citation: Astrophacus inca (Clark and Campbell 1942)
Rank: species
Basionym: Heliodiscus inca

Taxonomic discussion:
(Clark and Campbell) 1942 p.38 pl.3 fig.17; Caulet 1991; Heliodiscus inca in Clark & Campbell, 1942

Catalog entries: Heliodiscus inca

Original description: Shell like a sunburst with nine very long conical rays (in one specimen eight), about four times longer than the basal diameter, tips sharp, round in cross section, mostly equidistant; cortical shell lenticular, strongly biconvex, with small circular pores sunken below elevated concave rims with sepaloid points, these points rarely bifurcated distally and giving to the shell a thorny appearance, the points breaking the continuity of the edge, about fifteen or more pores across a diameter and three to five or more in the interradii, cavity of the pores cylindrical, and that of the surrounding calyx concave, wall thin; medullary shell small (less than 0.25 diameter of the cortical shell), extremely dense so that its structure cannot be made out clearly, supporting beams hyaline, few, apparently corresponding to the rays in number, bars of the cortical framework thin.

Diameter of the cortical shell, 180µm; of medullary shell, 43µm; of pores, 10µm; length of rays, 85µm; width of wall, 6.6µm. Distinguishing characters (rw): Heliodiscus inca n. sp. has long rays, while the other species of this collection have shorter rays.
Remarks on original description: [The authors here list this species under the subgeneric name Heliodiscetta and include the subgeneric name in the species name.


Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within Paleogene Period (23.03-66.04Ma, top in Chattian stage). Data source: Lazarus et al. 2015 - "P age group"
First occurrence (base): within Paleogene Period (23.03-66.04Ma, base in Danian stage). Data source: Lazarus et al. 2015 - "P age group"

Plot of occurrence data:


Caulet, J. (1991). Radiolarians from the Kerguelen Plateau, Leg 119. Proceedings of the Ocean Drilling Program, Scientific Results. 119: 513-546. gs

Clark, B. L. & Campbell, A. S. (1942). Eocene radiolarian faunas from the Mt. Diablo area, California. Geological Society of America, Special Papers. 39: 1-112. gs


Astrophacus inca compiled by the radiolaria@mikrotax project team viewed: 18-9-2021

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