Catalog - Globigerina anguliofficinalis

Catalog - Globigerina anguliofficinalis Catalog - Globigerina anguliofficinalis

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina anguliofficinalis Blow 1969

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 -> G -> Globigerina -> Globigerina anguliofficinalis

Other pages this level: << < G. aequatorialis, G. aequilateralis, G. aequilateralis involuta, G. affinis, G. alanwoodi, G. almadenensis, G. alpigena, G. altispira, G. ampliapertura, G. ampliapertura cancellata, G. anconitana, G. angipora, G. angiporoides, G. angiporoides minima, G. angulata, G. anguliofficinalis, G. antarctica, G. antillensis, G. apertura, G. applanata, G. aptica, G. aquiensis, G. arabica, G. archaeobulloides, G. ariakensis, G. aspensis, G. aspera, G. asperula, G. atlantica, G. atlantis, G. atlantisae> >>

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Globigerina anguliofficinalis

Citation: Globigerina anguliofficinalis Blow 1969

Taxonomic rank: species

Type specimens: PM P 49582

Type age (chronostrat): Lower to middle Oligocene, Zone P. 19 (= Globigerina sellii Pseuclohastigerina barbadoensis Concurrent-range zone), basal part of the Cipero Formation, Flat Rock Silt Member. Ranges from the upper part of Zone P.l7 (uppermost Eocene) to Zone N. 2 (upper Oligocene). Holotype (figs. 1 2) and figured paratypes (figs. 3-5) from north of San Fernando (sample Cb. 1964), Trinidad, West Indies.

Type locality: Holotype (figs. 1 2) and figured paratypes (figs. 3-5) from north of San Fernando (sample Cb 1964), Trinidad, West Indies.

Type repository: London, UK; NHM

Linked specimens: London, UK; NHM (PM PF 49582) London, UK; NHM (PM P 49582)

Current identification/main database link: Ciperoella anguliofficinalis (Blow 1969)

Original Description

The small test consists of about 11 chambers arranged in a low trochospire with 4½ chambers comprising the last whorl. The chambers are slightly to moderately inflated, closely appressed but separated by deeply incised ventral intercameral sutures. The intercameral sutures are marked by radial bands of less coarsely perforate wall and are distinctly 'U' -shaped as in Globigerina angulisuturalis Bolli. The distinct ventral intercameral slitures are formed by a sharp 'in-turning' of the chamber walls and this 'in-turning' gives a moderately lobate appearance to the equatorial profile of the test.

The umbilicus is small, but deep and open and is surrounded by an imperforate area which grades into the imperforate lip of the final chamber. The aperture of the final chamber is a low arch, somewhat asymmetrically placed with respect to the umbilicus. On the dorsal side the intercameral sutures are less deeply incised, less 'U-shaped' than on the ventral side. The spire is low, depressed and the early chambers indistinctly separated one from the other. The wall is relatively densely perforate and the pores open into distinct pits between small rugosities. Wall calcareous, radial hyaline.

Size:

Maximum diameter of holotype 0.27 mm.

Extra details from original publication

The holotype of this small but distinctive taxon, G. anguliofficinalis, is a comparatively phylogenetically advanced specimen of the lineage which leads from G. officinalis to G. angulisuturalis. The earlier, less phylogenetically advanced, forms of G. anguliofficinalis show only four chambers in the final whorl and little invagination of the ventral chamber walls so forming intercameral sutures which are only slightly U-shaped.

This taxon gradually evolves into G. angulisuturalis (at the top of Zone N. I Globigerina ampliapertura Partial-range zone) by the adoption of a truly five-chamber last whorl (see figs. 1-5) and the migration of the aperture to a symmetrical intraumbilical position. G. anguliofficinalis also differs from G. angulisuturalis in having a less highly arched aperture, a more closed umbilicus, less inflated chambers and less deeply incised intercameral sutures especially over the equatorial-peripheral marginal area and over the dorsal-peripheral shoulders of the chambers. Frequently, four-chambered forms show the presence of abortive, small final chambers which are less coarsely perforate.

References:

Blow, W. H. (1969). Late middle Eocene to Recent planktonic foraminiferal biostratigraphy. In, Bronnimann, P. & Renz, H. H. (eds) Proceedings of the First International Conference on Planktonic Microfossils, Geneva, 1967. E J Brill, Leiden 380-381. gs

Olsson, R. K., Hemleben, C., Coxall, H. K. & Wade, B. S. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Ciperoella. In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 46(Chap 7): 215-230. gs