Orbula ducalis


Classification: rads_cenozoic -> Theoperidae -> Bekomidae -> Orbula -> Orbula ducalis
Sister taxa: O. comitata, O. discipulus, O. ducalis, O. sp.,

Taxonomy

Citation: Orbula ducalis Foreman 1973
Rank: species
Basionym: Orbula ducalis

Catalog entries: Orbula ducalis

Original description: Cephalis subspherical in lateral view, subtriangular in transverse section, with corners of triangle truncate coinciding with position of vertical and secondary lateral bars which protrude as tiny thorns. Apical horn may be small, thorn-like, or larger and cylindrical. Cephalis and proximal thorax poreless, minutely papillate. Cephalis pitted apically, distally frequently nodose. Internally the collar stricture has six collar pores as in 0. comitata. Externally the collar stricture not distinct as the contour of the cephalis merges with that of the thorax. Thorax with two distinct flaring expansions, the distalmost much broader than the first; subtriangular in transverse section. Aperture constricted, subtriangular, surrounded by a rounded rim with surface minutely papillate. Three ribs extend from the collar stricture and terminate in three short feet at the point where the thorax constricts. Thoracic pores subcircular, arranged quincuncially in vertical rows, gradually increasing in size to the point of greatest expansion; surface tuberculate.

(Based on twenty specimens) Length of cephalis and thorax 100-150µm; greatest width of thorax 190-245µm, of aperture 120-160µm. Distinguishing characters (rw): This species is distinguished from 0. comitata and 0. discipulus as described under those species.

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:


logo

Orbula ducalis compiled by the radiolaria@mikrotax project team viewed: 8-8-2020

Taxon Search:
Advanced Search

Short stable page link: http://mikrotax.org/radiolaria/index.php?id=204839 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics