Desmospyris spongiosa


Classification: rads_cenozoic -> Trissocyclidae -> Acanthodesmiidae -> Desmospyris -> Desmospyris spongiosa
Sister taxa: D. mamillata, D. rhodospyroides, D. spongiosa, D. stabiloides, D. sp.

Taxonomy

Citation: Desmospyris spongiosa Hays 1965
Rank: species
Basionym: Desmospyris spongiosa
Taxonomic discussion: Hays 1965 p.173 pl.2 fig.1

Catalog entries: Desmospyris spongiosa

Original description: Shell heavy, spongy, divided into two segments by indistinct collar stricture. Cephalis bilocular with indistinct sagittal stricture, wall thick, pores circular, irregular in size and arrangement, one to two times width at bars. Sagittal ring D-shaped, joined at base to walls of cephalis by four beams, forming four large basal pores. Thorax subcylindrical, transverse section oval, basally truncate, slightly constricted at mouth, wall often spongy and thinner than wall of cephalis. Basal feet usually not present, but some specimens show several poorly developed feet.

Dimensions variable except height of sagittal ring which, on the 50 specimens measured, varied only between 75 and 85µm. Length of shell 100-170µm, breadth 105-150µm, depth 70-125µm.

Description based on 50 specimens from cores V.16-116, 720 and 750 cm; V-16-130, 400 and 450 cm; V-16-59, 860 and 900 cm. Distinguishing characters (rw): The internal skeleton of this species is identical with that of Triceraspyris antarctica (Haeckel), illustrated by Riedel [1958, p.230, text fig.3] except that Desmospyris spongiosa lacks the three basal feet. It may be related to Gorgospyris (Thamnospyris) (?) perplexus, Campbell and Clark [1944, p.37, pl.5, fig.18], but their description based on one specimen is insufficient to determine this relationship.
D. spongiosa is distinguished from other members of this genus by the spongy shell and the absence of well-developed terminal feet.
Remarks on original description: D. spongiosa does not occur in the recent surface sediments of the area. It is usually an abundant member of zone Phi and has a range similar to the range of Eucyrtidium calvertense, i.e., its upper limit corresponding approximately to the change from red clay to diatomite deposition. In two cores, V-16-66 and V-17-88, Desmospyris spongiosa is a much less important part of the Phi-zone assemblage than it is in the other cores that contain this zone. Both of these cores were taken north of the present position of the Polar Front and have considerable numbers of warm-water species in their tops. In V-16-66 Calocyclas amicae and Lamprocyclas maritalis are found in the Phi below 720 cm. It may be that D. spongiosa was more restricted to cold water than the other members of the zone and thus is poorly represented m cores containing warm-water species.

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within Neogene Period (2.59-23.03Ma, top in Piacenzian stage). Data source: Lazarus et al. 2015 - "N age group"
First occurrence (base): within Neogene Period (2.59-23.03Ma, base in Aquitanian stage). Data source: Lazarus et al. 2015 - "N age group"

Plot of occurrence data:

References:

Hays, J. D. (1965). Radiolaria and late Tertiary and Quarternary history of Antarctic Seas. In, Llano, G. A. (ed.) Biology of the Antractic Seas II. Antarctic Research Series (AGU). 5: 124-184. gs


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Desmospyris spongiosa compiled by the radiolaria@mikrotax project team viewed: 31-10-2020

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