Amphicraspedum prolixum


Classification: rads_cenozoic -> Spongodiscidae -> Euchitoniidae -> Amphicraspedum -> Amphicraspedum prolixum
Sister taxa: A. murrayanum, A. prolixum, A. sp.

Taxonomy

Citation: Amphicraspedum prolixum Sanfilippo & Riedel 1973
Rank: species
Basionym: Amphicraspedum prolixum
Taxonomic discussion: Sanfilippo and Riedel 1973 p.524 pl.11 figs.1-5 pl.28 fig.5

Catalog entries: Amphicraspedum prolixum

Original description: Elongated cylindrical skeleton, thickened at the ends, with or without a median swelling. Central structure in some specimens quite indistinct, consisting of only one or two rings, in others more distinct, with several closely spaced concentric rings. Two opposite arms greatly variable in length, consisting of a central core with pronounced longitudinal Structure, surrounded by a more irregularly spongy sheath which also covers the central structure and distally merges into the expanded terminations of the arms. Spongy terminations of the arms either knoblike, conical, or flatly expanded, and in many specimens hearing few to many spines or thorns which can sometimes be seen to be continuations of the longitudinal structural elements of the arms.

Based on 20 specimens] Length from center to end of spongy arm 235-830┬Ám.

Because specimens with very long arms are more susceptible to breakage than are those with short arms, this range of measurements is not as meaningful as it is with most other species. Specimens with very long arms will not to often be sufficiently well preserved to show a complete arm, as will specimens with shorter arms. Distinguishing characters (rw): This species is distinguished from other members of the A. prolixum group by the longer arms and more pronounced longitudinal structure, and from Amphymenium splendiarmatum Clark and Campbell (1942, p.46, pl. 1, figs. 12, 14) in that the latter has transversely chambered arms, not expanded terminally, and a less extensive spongy sheath. In rare specimens of A. prolixum, the expanded terminations of the arms are flanked by two spines similar to those of A. murrayanum.

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:

Sanfilippo, A. & Riedel, W. R. (1973). Cenozoic Radiolaria (exclusive of theoperids, artostrobiids and amphipyndacids) from the Gulf of Mexico, Deep Sea Drilling Project Leg 10. Initial Reports of the Deep Sea Drilling Project. 10: 475-608. gs


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Amphicraspedum prolixum compiled by the radiolaria@mikrotax project team viewed: 17-5-2021

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