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neptune records:
neptune records: 114
| Daughter taxa (time control age-window is: 0-800Ma) | Granddaughter taxa | ||||
| | | | Rhizosphaera neptune records: | |
| | | | Spongoplegma neptune records: 114 | |
Catalog entries: Rhizosphaeridae [no catalog entry yet]
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Published descriptions
Type genus: Rhizosphaera Haeckel 1860
Definition: Spherical entactinarians with a cortical and a single or double medullary shell. First medullary shell ovoid, or spherical, with spicule ectopically placed in its wall. Spicule with a median bar, two apical spines and four basal spines. All spines well developed, radially prolonged to the cortical shell, or short, prolonged only to the second medullary shell, or even shorter. Basal spines connected proximally by four arches on which the latticed skeleton of the first microspheric shell is built. Connection between these arches and first latticed medullary shell made by six bars forming a hexagon in apical view. Second medullary shell, when present, spherical, latticed or formed by a loose spongy fabric. Medullary shell connected to the cortical shell by six or usually many radial bars that may extend outside into external spines. Primary spines originate from the spicule or the first medullary shell, and/or secondary spines originate in the latticed or spongy second medullary shell.
Remarks: From the point of view of the nucleo-axopodial structure the living members of this group are of the centroaxoplastidian type (Hollande and Enjumet, 1960). The presence of an initial spicule was not mentioned by any of the previous authors, but it is always present, although difficult to recognise when the first microspheric shell is not observed apically or laterally, or when it is screened by a rather thick spongy external medullary fabric. The spicule is always located at the narrower pole of the ovoid first shell.
Range: Jurassic (Tithonian or older) to Recent, but more frequent during the Cainozoic.
Geological Range:
Last occurrence (top): Extant. Data source: Total of ranges of the species in this database
First occurrence (base): within Neogene Period (2.59-23.03Ma, base in Aquitanian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
References:
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Rhizosphaeridae compiled by the radiolaria@mikrotax project team viewed: 5-10-2026
Short stable page link: https://mikrotax.org/radiolaria/index.php?id=206416 Go to Archive.is to create a permanent copy of this page - citation notes |