Oroscena carolae


Classification: rads_cenozoic -> Orosphaeridae -> Oroscena -> Oroscena carolae
Sister taxa: O. carolae, O. sp.

Taxonomy

Citation: Oroscena carolae Friend & Riedel 1967
Rank: species
Basionym: Oroscena carolae
Taxonomic discussion: Friend & Riedel 1967 p. 225 Pl. 2 Figs 9-10 Pl. 3 Figs. 1-2

Catalog entries: Oroscena carolae

Original description: Shell single, subspherical to ellipsoidal, rarely ovoidal. Lattice coarse to fine. Upper spines club-shaped to cylindrical; lower spines variable. Lattice lamellar, with pores varying greatly in size between specimens. Pores are usually triangular or quadrangular, sometimes slightly rounded, and often appear more rounded when viewed obliquely because of the thickness of the bars. Bars circular to elliptical in cross section, the radial dimension being the greater one. Ribs seldom conspicuous but can usually be distinguished in apical area, where they often form a three-rayed figure or a cross. Spines very approximately 20-40 in number. Spines on upper end of shell are radial, and those on lower end tend to be curved downward. Bases of spines rarely elevated above shell surface. Spines at upper end of shell vary from short and club-shaped to long, thin and rod-shaped, between individuals. Spines at lower end of shell rod-shaped, laterally branched, rarely digitately branched, or club-shaped with branched tip Surface texture of spines usually rough.

(Based on 26 specimens randomly selected from approximately 3,100 observed) Shell length 0.8-1.5 mm., breadth 0.8-1.4 mm. Length of spines at upper end of shell 0.8-1.0 mm. Diameter of pores 20-290┬Ám. Distinguishing characters (rw): 0. carolae differs from all other observed species of Oroscena in this size range in the following combination of characters: bars tending to be wider radially than tangentially, ribs not very conspicuous, spine bases generally not pyramidally elevated, upper spines not digitately branched and not curved and flattened.
The above broad species description is based on more than 3,000 individuals, almost all of which have their lower spines broken off. The characters which remain (size of pores, prominence of ribs, form and number of unbroken spines, and shape of shell) all vary slightly but in no discernible pattern which could be used to subdivide the group. If only complete specimens with intact lower spines were taken into account, it might be possible to subdivide the group into more than one species, but the majority of incomplete specimens could not be assigned among the species thus defined. For the present, therefore, a broadly defined species seems to have practical advantages.
Some specimens (plate 3, figure 3) from the upper part of the range of this species have generally larger pores separated by bars which are occasionally wider tangentially than radially. These individuals are only hesitantly included in this species.

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within Paleogene Period (23.03-66.04Ma, top in Chattian stage). Data source: Lazarus et al. 2015 - "P age group"
First occurrence (base): within Paleogene Period (23.03-66.04Ma, base in Danian stage). Data source: Lazarus et al. 2015 - "P age group"

Plot of occurrence data:

References:

Friend, J. K. & Riedel, W. R. (1967). Cenozoic orosphaerid radiolarians from tropical Pacific sediments. Micropaleontology. 13(2): 217-232. gs


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Oroscena carolae compiled by the radiolaria@mikrotax project team viewed: 22-10-2020

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Short stable page link: http://mikrotax.org/radiolaria/index.php?id=204845 Go to Archive.is to create a permanent copy of this page - citation notes



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