Catalog entries: Tholospyris devexa
Original description: All representatives of Tholospyris devexa are characterized by a lattice shell and a pair of slender sagittal spines at the front-base of the sagittal ring. This subspecies is characterized by a tribladed basal ring.
Sagittal ring subpolygonal. 57 to 70 microns high, 48 to 54 microns thick, joined directly to front and back of lattice shell. Complete specimens have slender apical connector bar and no apical or axial spines. Short, vertical spine projects near base of sagittal ring ; short, broad, frontal spine. Single sculptured tubercle projecting from base of sagittal ring at intersect with primary lateral processes. On some specimens, the only basal connector bars are primary lateral bars joined to the basal ring; other specimens have primary lateral spines and no basal connector bars. A pair of short, sagittal-ring spines projects from the front-base of the sagittal ring.
Basal ring oval, indented sagittally, 85 to 120 microns wide, 40 to 54 microns thick, tribladed, enclosing two or four basal pores. Basal ring joined to front-middle and back-base of sagittal ring; lattice bars joined to basal ring irregular in number and position. Lattice shell 100 to 135 microns wide, 165 to 212 microns high, surrounding apex and base of sagittal ring; slight horizontal constriction at basal ring. Broad lattice bars separating small, subrounded, lattice pores on the lateral portions of the lattice shell. Three pairs of very large, sagittal. lattice pores covered by thin, perforated, lattice plates. Portions of lattice shell surrounding apex and base of sagittal ring composed of delicate, smooth, lattice bars separating many small, subcircular, lattice pores. Three tribladed lattice bars joining middle and apex to sagittal ring. No frontal, vertical or sternal pores. No lattice spines or lattice tubercles. Distinguishing characters (rw): Representatives of Tholospyris devexa devexa are distinguished from those of Tholospyris baconiana, Tricolospyris leibnitziana, Tholospyris procera and the type species of Tholospyris, T. cortinisca. by the presence of a pair of sagittal-ring spines at the front-base of the sagittal ring.
The minute protrusions on the single sagittal-ring tubercle can only be examined by stereoscan electron microscopy, and they were illustrated by Goll (1972, p1. 77, figs. 2-3). The pair of front-basal, sagittal-ring spines of Tholospyris devexa are homologous with the front of the basal ring of Tholospyris baconiana.
Remarks on original description: first appears within or directly below the Olduvai Event.
Last occurrence (top): within (-Ma, top in "Holocene" stage). Data source:
First occurrence (base): within (-Ma, base in stage). Data source:
Plot of occurrence data:
Tholospyris devexa devexa compiled by the radiolaria@mikrotax project team viewed: 25-11-2020
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