radiolaria - rads_cenozoic - Amphipternis alamedaensis radiolaria - rads_cenozoic - Amphipternis alamedaensis

Amphipternis alamedaensis

Classification: rads_cenozoic -> Amphipyndacidae -> Amphipternis -> Amphipternis alamedaensis
Sister taxa: A. alamedaensis, A. clava, A. sp.


Citation: Amphipternis alamedaensis
taxonomic rank: species
Basionym: Phormocampe alamedaensis Campbell & Clark 1944

Catalog entries: Phormocampe alamedaensis

Original description: Shell rather large, tall, narrow, and generally conical (20-25°); cephalis (primary joint) inflated and like a prominent knob or handle; thorax, abdomen, and postabdomen (terminal 6 or 8 joints) generally similar in shape, increased regularly in diameter and breadth from initial to ultimate end, except penultimate joint which is relatively largest, and out of proportion with others, shell joints distinctly separated by transverse septal bands, individual indentations on each side of bands, and by separate median bulges which give lateral contour character of a saw edge, joints sometimes asymmetrical; ultimate joint incurved, with free edge having numerous (about 22), tiny, triangular teeth; wall uniformly thin; surface trim; pores uniformly subcircular, increased in diameter relative to joint in which they lie, with smallest at cephalic end, but wholly lacking in cephalis, and in penultimate joint they are smaller in diameter than in joints immediately above and below, pores shallow, distinctly separated and well spaced in the clear shell material, about 12-16 around joint, and in 5-6 vertical tiers, usually in subregular (mildly spiral) rows in either direction.
Remarks on original description: The authors here list Phormocampe alamedaensis under the subgeneric name Cyrtocorys and include the subgeneric name in the species name.[comment from RadWorld database]


Biogeography and Palaeobiology

Similar species


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:



Amphipternis alamedaensis compiled by the radiolaria@mikrotax project team viewed: 17-6-2024

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