radiolaria - rads_cenozoic - Periarachnium <title>radiolaria - rads_cenozoic - Periarachnium


Classification: rads_cenozoic -> Plagiacanthidae -> Lophophaenidae -> Periarachnium
Sister taxa: << < Archipilium, Botryopera, Ceratocyrtis, Cryptogyrus, Dictyocephalus, Dictyocryphalus, Entepipedus, Gondwanaria, Lipmanella, Lithocampana, Lithomelissa, Lophophaena, Marimoum, Mitrocalpis, Pelagomanes, Periarachnium, Peromelissa, Phormacantha, P. inc sed castanoides, Plectacantha, Pseudocubus, Pseudodictyophimus, Pteroscenium, Steganocubus, Tripodocyrtis, Trisulcus
Daughter taxa (time control age-window is: 0-800Ma)
Periarachnium pauliani

neptune records:
Periarachnium periplectum

neptune records:


Citation: Periarachnium Haeckel 1882
Rank: genus
Basionym: Periarachnium Haeckel 1882
Taxonomic discussion: Nishimura 1990 reported differences in primary spicules and assigned this genus to the Theoperidae. Suzuki placed in Lampromitridae. Leaving in Lophophaenidae for now based on similar overall morphology to Ceratocyrtis - dbl 25.8.20.

Catalog entries: Periarachnium

Original description: 2a.Tribus: Sethocorida .Dyocyrtida aperta eradiata.
A. Sethocorida limbata = Lophophaenida. (Sethocorida margine ostii. laevi aut succiso).
AII. acuta (capitulo spinoso, non laevi).
IIb. secundo articulo conico, ostio nec coarctato nec dilatato.
b++ spinis capituli pluribus.
§4. secundo articulo spinis pallio arachnoideo incluso.

Translated description: 2a. Tribe: Sethocorida. Open eradiate dyocyrtids.
A. Sethocorida with a girdle = Lophophaenida (Sethocorida with a smooth or truncate apertural margin).
AII. Acute (with cephalis spiny, not smooth).
IIb. With the second segment conical and the aperture neither constricted nor dilated.
b++ With more than one cephalic spine.
§4. With the second segment enclosed by an arachnoidal mantle. (Translated from Latin by E.M.R. and W.R.R.)]




Biogeography and Palaeobiology

Similar species

Geographic distribution


Phylogenetic relations

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within (-Ma, top in "Holocene" stage). Data source:
First occurrence (base): within (-Ma, base in "Holocene" stage). Data source:

Plot of occurrence data:



Periarachnium compiled by the radiolaria@mikrotax project team viewed: 30-1-2023

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