pforams@mikrotax - Sigalia rugocostata

Sigalia rugocostata

Classification: pf_mesozoic -> Heterohelicidae -> Sigalia -> Sigalia rugocostata
Sister taxa: S. carpatica, S. decoratissima, S. deflaensis, S. rugocostata, S. sp.


Citation: Sigalia rugocostata Nederbragt, 1991
Rank: Species
Basionym: Sigalia deflaensis rugocostata
Taxonomic discussion: As in the biserial S. deflaensis, there is considerable variation in the strength of the ornamentation and in the extent to which the sutures are raised. Forms with only slightly raised sutures grade into V. eggeri, and forms with strongly raised sutures and very fine costae grade into S. decoratissima. However, the complete range of variation is not found in a single sample. In the El Kef section, S. rugocostata is accompanied by common V. eggeri, and rare specimens that are transitional to S. decoratissima. In samples that contain a S. decoratissima population, S. deflaensis and S. rugocostata are very rare and V. eggeri specimens are absent. [copied from Chronos database]

Type images:

Original description: Early chambers biserial, gradually to rapidly increasing in size when added, followed by up to 6 sets of multiserial chambers. Individual chambers and chamberlets subglobular, wider than high or deep; sutures of earlier chambers raised above the surface of the test. Chamber surface as well as sutures covered by thin to thick costae; ornamentation and raised sutures more strongly developed on the early part of the test. Apertures a simple arc, bordered by small flanges.

Entries in the Catalog of original descriptions: Sigalia deflaensis rugocostata

Emended description:


Wall type:


Character matrix
test outline:Subtriangularchamber arrangement:Multiserialedge view:Compressedaperture:Multiple
sp chamber shape:Inflatedcoiling axis:N/Aperiphery:N/Aaperture border:Thin flange
umb chbr shape:Inflatedumbilicus:N/Aperiph margin shape:N/Aaccessory apertures:None
spiral sutures:Raised beadedumb depth:N/Awall texture:Finely costateshell porosity:
umbilical or test sutures:Raised beadedfinal-whorl chambers:4.0-7.0 N.B. These characters are used for advanced search. N/A - not applicable

Geological Range:
Last occurrence (top): within D. asymetrica zone (84.19-86.71Ma, top in Santonian stage). Data source: [copied from Chronos database]
First occurrence (base): within D. asymetrica zone (84.19-86.71Ma, base in Coniacian stage). Data source: [copied from Chronos database]

Plot of range and occurrence data:


Nederbragt, A. J. (1991). Late Cretaceous biostratigraphy and development of Heterohelicidae (planktic foraminifera). Micropaleontology. 37: 329-372. gs


Sigalia rugocostata compiled by the pforams@mikrotax project team viewed: 28-9-2022

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Le Coze

Citation: Sigalia rugocostata (Nederbragt, 1991) no brackets needed no genus transfer.

Jeremy Young (UK)


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