radiolaria - rads_cenozoic - Protoscenium

Protoscenium


Classification: rads_cenozoic -> Plagiacanthidae -> Plagiacanthidae (ss) -> Protoscenium
Sister taxa: Plagiacantha, Plectagonidium, Protoscenium, Rhabdolithis, Tetraplecta
Daughter taxa (time control age-window is: 0-800Ma)
Protoscenium simplex

neptune records:
Protoscenium sp.

neptune records:

Taxonomy

Citation: Protoscenium Jørgensen 1905
Rank: genus
Basionym: Protoscenium

Catalog entries: Protoscenium

Original description: The usual four, primary spines are present, all about equally developed, the apical one (D), however, perhaps best. The basal spines form a very flat pyramid; they are most distinctly directed downwards at the free ends. The primary verticil with three branches on each main spine is well developed, on each of the three basal ones, however, the downwards pointing (outwards pointing) branch is wanting, while the two others everywhere point regularly upwards and outwards. On the apical spine (D) all three branches are well developed and lie about parallel to the basal spines. All the main spines have also a protruding middle stem, which is about equal in length to the primary branches. Between sets of two of those primary branches which are nearest and belonging to different main spines, a strong, connecting arch is developed near their ends. Of such arches, there are altogether 9, 3 basal and 6 apical ones. Of the three basal ones, one runs in a ventral direction, between the ventral branches of the lateral spines, the two others laterally, between the dorsal branches of the lateral spines and the corresponding branches of the dorsal spine (A). From the dorsal branch of the apical spine two apical arches extend to the right and left branch of the dorsal spine, and in the same way, two apical arches from the apical spine's (D) right lateral branch to the two branches of the right, lateral spine, and two apical arches from the left, lateral branch of the apical spine to the two branches of the left, lateral spine. These arches all meet in twos the branches at the same point, at a short distance from their end. There may also he found a weaker, secondary arch branch extending from the same points of the primary branches, but connecting together in twos the branches of the same main spine, or connecting these branches with the protruding middle stem. In this way, a network which is, on the whole, very open, is formed of very large meshes and thin beams with 9 short spikes protruding from a regular verticil of three branches (the 6 spikes being basal, the 3 apical) and 4 longer simple spikes (3 basal, 1 apical).
Remarks on original description: Jorgensen here considers his specimen Protoscenium simplex [Cleve] to be synonymous with Plectanium simplex Cleve,1899a [pl.3, fig.3]. However, Frenguelli [1951, p.281] indicates that the Cleve specimen is a silicoflagellate. Because Jorgensen's specimen is probably a radiolarian, we consider it, Protoscenium simplex [Cleve] in Jorgensen1905, pl.133, pl.15, fig.69, x660 rather than Cleve's specimen to be the type species by monotypy of Protoscenium.

Description


Morphology:


Size:

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source: Total of range of species in this database
First occurrence (base): at base of Gelasian Stage (0% up, 2.6Ma, in Piacenzian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Jørgensen, E (1905). The protist plankton and diatoms in bottom samples: Radiolaria. In, Nordgaard (ed.) Hydrographical and biological investigation in Norwegian Fjord. 49-151. gs


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Protoscenium compiled by the radiolaria@mikrotax project team viewed: 7-8-2022

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