radiolaria - rads_cat - Acrosphaera australis radiolaria - rads_cat - Acrosphaera australis

CATALOG OF ORIGINAL DESCRIPTIONS: Acrosphaera australis Lazarus 1990

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 -> A -> Acrosphaera -> Acrosphaera australis
Other pages this level: A. arachnodictyna, A. australis, A. collina, A. cuniculiauris, A. echinoides, A. erinacea, A. inflata, A. labrata, A. mercurius, A. muse, A. pacifica, A. pseudarktios, A. simpla, A. spinosa coniculispina, A. spinosa fasciculopora, A. spinosa hamospina, A. spinosa longispina, A. streblospina, A. transformata

Acrosphaera australis

Citation: Acrosphaera australis Lazarus 1990
Taxonomic rank: species
Described on page(s) : p.712
Type specimens: pl.1, figs.1-2 (holotype), 3-4 (paratypes), 5-6; pl.2, fig.6
Type repository: Type specimens deposited in the paleontological collections of the Geologisches Institut, ETH Zurich.
Family (traditional): Collosphaeridae
Family (modern): Collosphaeridae

Current identification/main database link: Acrosphaera australis Lazarus 1990


Original Description

Smooth, hyaline sphere with large, irregularly spaced and shaped pores extended outward radially into tubes tube tips flared and in many of the pores joined to adjacent tube tips to form outer layer of hyaline bands or bridges between tube tips.

Etymology:
australis= southern.

Extra details from original publication
Distinguishing characters: Distinguished from other collosphaerids by the presence of an outer layer of elevated bands joining tube tips.
Phylogeny: Evolves from Acrosphaera murrayana (Haeckel) Strelkov and Reshetnyak, 1971 by the joining together of the flared tips of the tubes. This evolutionary transition is clearly seen in Leg 113 material, with transitional specimens being quite common in populations at the base of A. australis' range. The first appearance is defined by the first occurrence of specimens with more than one pair of pores joined by well developed bands. Specimens of A. murrayana still occur in these early, transitional populations.
Taxonomy: The generic assignment follows the revisions of Strelkov and Reshetnyak (1971) and Bjørklund and Goll (1979), which divide the collosphaerids into genera based on the presence or absence of tubes or spines. As noted by Bjørklund and Goll, even the current generic divisions in the collosphaerids are artificial, as evolutionary transitions between spinose, tubular, and unornamented forms are seen in fossil lineages. This is true in particular of the Acrosphaera murrayana - A. australis lineage, since A. murrayana is a spinose form, while A. australis is a tubular one. Acrosphaera is retained however until a better generic taxonomy for the collosphaerids becomes available.

References:

Lazarus, D. (1990). Middle Miocene to Recent radiolarians from the Weddell Sea, Antarctica, ODP Leg, 113. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 709-727. gs


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Acrosphaera australis compiled by the radiolaria@mikrotax project team viewed: 13-5-2025

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