Classification: rads_cenozoic -> Spongodiscidae -> Spongodiscidae inc sed -> Plectodiscus
Sister taxa: Amphirhopalum, Coccolarcus, Euchitonia, Ommatogramma, Plectodiscus, Porodiscus, Spongasteriscus, Spongobrachium, Stylospongia, Tholodiscus, Trigonastrum
Daughter taxa (time control age-window is: 0-800Ma)
Plectodiscus bergontianus

neptune records:
Plectodiscus sp.

neptune records:


Citation: Plectodiscus Kozlova in, Petrushevskaya & Kozlova 1972
Rank: genus
Basionym: Plectodiscus

Catalog entries: Plectodiscus

Original description: Thin, biconvex skeleton, with oval, less frequently circular outline, consisting of frontal, equatorial, and sagittal girdles. The closed-spiral structure of girdles is of the Spironium type: wings of the same type of girdle form a one-half turn of the spiral, and at the point of their junction overlap each other. Fist system has fully developed girdles, its dimensions are 40-50µm; in the rest of the girdles only the equatorial girdle is fully developed, both sagittal and frontal girdles terminating at the point of their junction with the previous system. Distance between rings is greater than is the diameter of the central chamber. Inner spines are indistinct; rim of the disc is smooth or is covered by numerous short spines.

Depending on the degree of inclination of the plane of the girdles in relation to the main axes of the skeleton, the equatorial girdles appear from the surface (rest of girdles in corresponding cross-section) in the form of rings, as a single or double spiral, or in the form of rings connected by zigzag radial lines.


Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): at top of Piacenzian Stage (100% up, 2.6Ma, in Piacenzian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Aquitanian Stage (0% up, 23Ma, in Aquitanian stage). Data source: Total of range of species in this database

Plot of occurrence data:


Petrushevskaya, M. G. & Kozlova, G. E. (1972). Radiolaria: Leg 14, Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 14: 459-648. gs


Plectodiscus compiled by the radiolaria@mikrotax project team viewed: 15-5-2021

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