radiolaria - rads_cenozoic - Astrophacus linckiaformis

Astrophacus linckiaformis

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


Citation: Astrophacus linckiaformis (Clark and Campbell) Caulet 1986
Rank: species
Basionym: Heliodiscus linckiaformis

Catalog entries: Heliodiscus linckiaformis

Original description: Shell small, with five short rays dividing the shell into a bivium and trivium with the bilateral axis passing through the middle ray of the trivium as in the starfish, spines hardly twice the diameter of a pore in length, strongly four-angled, angles decurrent near the tip, distally sharp, spreadingat the base with sweepingly concave sides to the expanded base and with riblets extending into the ray; corticular shell lenticular, very strongly biconvex, with very large, fairly uniform, subcircular pores, these sometime confluent, two or three flowing together with a common rim, the pores with very thin rims, about fifteen or sixteen across a diameter and six to nine in an interradius; cavities of the pores cylindrical; surface flush, with slight points; framework clear but with thick bars; medullary shell less than 0.3 the diameter of the cortical shell, with few large, coarse pores and thick, dense framework, supporting beams twelve, thin, more or less equally distributed around the periphery.

Diameter of cortical shell, 150µm; of medullary shell, 40µm; of pores, 12.2µm; thickness of wall, 6.6µm; length of ray, 21µm. Distinguishing characters (rw): Heliodiscus linckiaformis n. sp. differs from H. pentasteriscus n. sp. in smaller size (150 as against 200µm) in shorter rays (21 as against 60.6µm) and in very much larger pores (twice the diameter of those of the latter). Both species have five 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:



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

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