radiolaria - rads_cenozoic

Dumitrica, in De Wever et al. 2001 -

Type genus: Heliodiscus Haeckel 1881

Definition: Test consisting of medullary and cortical shells. Medullary shell double
with eccentric microsphere. Cortical shell lenticular, discoid, ovoid or spherical, single
or multiple, connected to medullary shell by numerous radial bars.

Remarks: When lenticular or discoid, the members of this family resemble some
members of the family Coccodiscidae from which they differ in the eccentric position
of the microsphere.

Range: Palaeocene to Recent.

Lazarus et al. 2021 -

Spumellarians with a double medullary shell, and with the innermost located
eccentrically. Cortical shell, in the original definition by Haeckel , was the key character -
lenticular or discoidal, usually with radiating spines in equatorial plane. This definition was
modified by the work of Hollande and Enjumet (1960), Dumitrica (1978) and others to be based on
the, discovered by them, eccentric innermost medullary shell and now includes genera with
spherical or ellipsoidal cortical shells more typical of Actinommidae, e.g. Excentrodiscus and
Excentrosphaerella.

Geological Range:
Last occurrence (top): Extant. Data source: Total of ranges of the species in this database
First occurrence (base): within Paleogene Period (23.03-66.04Ma, base in Danian stage). Data source: Total of ranges of species in this database

Daughter taxa (time control age-window is: 0-800Ma)		Granddaughter taxa
	Astrophacus neptune records: 15	Astrophacus inca Astrophacus linckiaformis Astrophacus sp.
	Excentrococcus neptune records: 93	Excentrococcus annulatus Excentrococcus sp.
	Excentrosphaerella neptune records: 3	Excentrosphaerella sphaeroconcha Excentrosphaerella sp.
	Heliodiscus neptune records: 299	Heliodiscus asteriscus Heliodiscus echiniscus Heliodiscus hexasteriscus Heliodiscus tunicatus Heliodiscus sp.

Heliodiscidae

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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