Catalog entries: Orbula discipulus
Original description: Cephalis subspherical, poreless, but with numerous circular, pore-shaped depressions, bearing a slender cylindrical horn never observed complete, and sometimes tiny vertical and secondary lateral spines. Surface of cephalis and proximal thorax roughened with minute papillae. Collar stricture well defined externally, internally with six collar pores, as for 0. comitata but with collar structures not so weak. Thorax unevenly campanulate, except distally where it constricts to terminate in an apertural rim with surface minutely papillate. Three ribs extend approximately two-thirds down the length of the thorax, terminating as three short, rodlike feet at the point where the thorax begins to constrict. Thoracic pores angular to subcircular, irregular in size and arrangement; surface tuberculate.
(Based on twenty specimens). Length overall, exclusive of horn, 180-230µm; greatest width of thorax 190-255µm, diameter of aperture 105-140µm. Distinguishing characters (rw): This species is distinguished from 0. ducalis by its shape and irregularly arranged pores, and from 0. comitata by its greater size and irregularly arranged and relatively smaller pores.
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:
Orbula discipulus compiled by the radiolaria@mikrotax project team viewed: 5-8-2020
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