CATALOG OF ORIGINAL DESCRIPTIONS: Eoglobigerina operta Lipps 1964

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.

Higher levels: pf_cat -> E -> Eoglobigerina -> Eoglobigerina operta
Other pages this level: E. appressa, E. edita praeedita, E. eobulloides simplicissima, E. extensa, E. ferreri, E. fodina, E. maamouri, E. operta

Eoglobigerina operta

Citation: Eoglobigerina operta Lipps 1964
Rank: Species
Type locality: Eoglobigerina operta occurs near the top of the section studied, in Mohnian sample 34.
Type age (chronostrat): Miocene
Type specimens: Types: Holotype UCLA no. 34749; 100 unfigured paratypes UCLA no. 34750; 10 unfigured paratypes USNM no. 641569; all from sample 34, Mohnian.
Type repository: Los Angeles; University of California, , USA

Linked specimens: USNM-641569

Current identification/main database link:

Original Description
Test free, trochospiral, about 2 1/2 whorls, convex on spiral side, slightly concave to convex on umbilical side, umbilicus small, deep when open, or may be covered, outline lobulate, circular in small specimens, quadrate in large ones, edges broadly rounded on umbilical side, more sharply rounded on spiral side. Chambers inflated, spherical in early stages, becoming elongate tangential1y, chambers larger where adjacent to earlier chambers, then tapering and becoming smaller toward aperture, 4 to 5 in last whorl, latest chambers tend to coil onto umbilical side of test, final chamber commonly reduced and covering umbilicus. Sutures radial, depressed, more deeply incised on umbilical side. Wall smooth, very finely perforate. Aperture extraumbilical, semicircular, with small protruding lip, commonly covered by small modified terminal chamber with an umbilical-extraumbilical opening.

Size: Greatest diameter of holotype .204 mm; greatest thickness .136 mm.

Etymology: The specific name is from the Latin opertus, meaning "cover, hide," in reference to the covered or hidden aperture and umbilicus.

Extra details from original publication
Remarks: This new species is differentiated from other species by its tangentially elongate, tapering chambers. Globorotalia acostaensis Blow, 1959, and G. birnageae Blow, 1959, are similar to E. operta but the chambers are not as wide in the former. The generic assignment of Blow's species could not be determined from the original descriptions and illustrations, and they may not be related to Eoglobigerina.


Lipps, J. H. (1964). Miocene planktonic foraminifera from Newport Bay, California. Tulane Studies in Geology and Paleontology. 2: 109-133. gs V O


Eoglobigerina operta compiled by the pforams@mikrotax project team viewed: 28-10-2020

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