CATALOG OF ORIGINAL DESCRIPTIONS: Panarium penultimum Riedel 1957

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.

Higher levels: rads_cat -> P -> Panarium -> Panarium penultimum
Other pages this level: P. annularium, P. artophorum, P. facettarium, P. penultimum, P. pipettarium, P. tubularium

Panarium penultimum

Citation: Panarium penultimum Riedel 1957
Rank: species
Type specimens: pl.1, fig.1
Type repository: Holotype. Swed. D. S. Exped. Core 73, 911.5-912.5 cm. X 380. Probably S.I.O., La Jolla, California.
Described on page(s) : p.76
Family (traditional): Coccodiscidae

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Current identification:

Original Description
Cortical twin-shell shell constricted equatorially, with circular to irregularly rounded pores: its surface hearing prominent, obtuse protuberances. Distal chambers hemispherical, as caps on either end of cortical twin-shell, their length usually 0.2-0.3 that of twin-shell, somewhat narrower than twin-shell. Each cap surmounted by a spongy tube or tongue-shaped column, of which the width is approximately half that of the maximum breadth of twin-shell, or less. Outer medullary shell lenticular, inner one spherical.

Length of cortical twin-shell usually 100-12µm, its maximum breadth 80-105µm. Length of polar caps 25 - 40µm, of spongy polar columns 25-25-80µm. Distinguishing characters (rw): This species differs from other described members of the genus in the heavy protuberances of the cortical twin-shell. The polar terminations of the species here described are spongy columns rather than "hollow fenestrated tubes", but it seems undesirable to erect a separate genus based on this character. The definition of the genus Panarium should therefore be somewhat broadened to include forms in which the polar columns are spongy, and not hollow. Phylogeny (rw): There are indications that it was developed from a form having less conspicuous polar caps, and wider terminal spongy columns.


Riedel, W. R. (1957b). Radiolaria: a preliminary stratigraphy. Reports of the Swedish Deep-Sea Expedition, 1947-1948. 6(3): 59-96. gs


Panarium penultimum compiled by the radiolaria@mikrotax project team viewed: 24-1-2021

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