pforams@mikrotax - Rugotruncana pforams@mikrotax - Rugotruncana


Classification: pf_mesozoic -> Rugoglobigerinidae -> Rugotruncana
Sister taxa: Archaeoglobigerina, Bucherina, Kuglerina, Plummerita, Rugoglobigerina, Rugotruncana, Trinitella
Daughter taxa (time control age-window is: 0-800Ma)
Rugotruncana circumnodifer

Rugotruncana nothi

Rugotruncana subcircumnodifer

Rugotruncana sp.
Specimens which cannot be assigned to established species


Citation: Rugotruncana Brönnimann&Brown 1956
taxonomic rank: Genus
Type species: Rugotruncana tilevi Brönnimann and Brown, 1956
Taxonomic discussion: The revised definition of this genus given by Pessagno (1967, *2387, p. 368) stated, in part "coarse rugosities or costellae, always arranged in a distinctive meridorial [sic] pattern, present on the surface of the test," but does not agree with the characters of the type species. Topotypes of R. tilevi (received from N. K. Brown) do not have the meridional alignment of costellae shown in the original drawing. Furthermore, as was correctly shown in the original illustrations, the chambers of R. tilevi are much more globular and the costae more widely spaced than in Globotruncana circumnodifer subsp. subcircumnodifer Gandolfi, hence the two species are not synonymous as had been stated by Pessagno, and R. tilevi remains the correct name for the type species of Rugotruncana.

Original description: The calcareous hyaline test is trochospirally coiled. The small early chambers are globular, inflated, and globigerine-like. Later chambers are very slightly to strongly flattened and exhibit a keeled, imperiorate, peripheral band. The early chambers are smooth walled, but some or all later chambers exhibit fine discontinuous costellae or traces of costellae. The principal aperture is rounded, interiomarginal, and opens into a relatively large umbilicus. Long apertural flaps extend into the umbilicus, and in later chambers form a protruded, imperforate, umbilical cover-plate with accessory apertures.

Entries in the Catalog of original descriptions: Rugotruncana

Distinguishing features:
Parent taxon (Rugoglobigerinidae): Test trochospiral, chambers inflated, periphery rounded, not carinate; wall with pustules, costellae, or other rugosities; aperture umbilical, with portici or tegilla.
This taxon: Test with a low trochospiral coil, early chambers subglobular and inflated, later chambers slightly compressed, sutures curved on the spiral side and continuous with the peripheral carina, straight, radial, and depressed on the umbilical side, umbilicus wide, periphery with double-keeled imperforate carinal band; wall calcareous, finely perforate, surface strongly pustulose, adjacent pustules may coalesce into short costellae without distinct alignment, although resulting in a rugose surface; primary aperture interiomarginal, umbilical, elongate portici in the early chambers, later with distinctly protruding tegilla provided with accessory apertures.

Geological Range:
Last occurrence (top): at top of P. hariaensis zone (100% up, 66.4Ma, in Maastrichtian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within R. calcarata zone (75.06-75.91Ma, base in Campanian stage). Data source: Total of ranges of species in this database

Plot of range and occurrence data:


Loeblich, A. R. & Tappan, H. (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York. 1-1059. gs


Rugotruncana compiled by the pforams@mikrotax project team viewed: 24-6-2024

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Comments (2)

Le Coze

The taxonomic discussion states that G. tilevi remains the correct name for the type species of Rugotruncana but it is included in the synonyms of G. circumnodifer?

Jeremy Young(UK)

Indeed, I will point his out to Brian