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Rhizosphaera acrocladon Blueford, 1982

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Description: Three or four shells, average diameters of 250, 200, 70, and 20 Ám. Twenty to 40 conical spines, radiating from innermost outer shells, by-spiny, with pores irregularly elliptical, forming spongy delicate meshwork in some specimens. Pores of inner shelss of irregular shapes and varying sizes.
Holotype: Plate 3, figure 5, DSDP Site 66, core 1-4, section 3, 27-29 cm, England finder Y 29/2 (USNM 315055).
Distinguishing features:Large, with threee or four shells, many short, conical spines and large elliptical pores on the outer shell. Differs from Rhizosphaera serrata Haeckel, 1887 by possessing conical spines with no arches at the base and more robust inner shells.
Derivation of name: In reference to the termination of spines, from the Latin acro, sharp; and Greek clado, branch.
Occurence: Sparse presence at Sites 77 and 66 and absence at Site 289 probably results from the same conditions as for Rhizoplegma densum. A lower limit of this species is distinguishable in cores 77B-23 and 66-5. No upper limit has been determined.
Blueford 1982


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