CATALOG OF ORIGINAL DESCRIPTIONS: Globorotalia (Acarinina) broedermanni subsp. anapetes Blow 1979

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 -> Globorotalia (Acarinina) -> Globorotalia (Acarinina) broedermanni anapetes
Other pages this level: G. (Acarinina) appressocamerata, G. (Acarinina) broedermanni anapetes, G. (Acarinina) cuneicamerata, G. (Acarinina) matthewsae, G. (Acarinina) praeaequa, G. (Acarinina) praeangulata

Globorotalia (Acarinina) broedermanni anapetes

Citation: Globorotalia (Acarinina) broedermanni subsp. anapetes Blow 1979
Rank: sub-species
Type locality: B. P. sample RS.24, Kilwa, Tanzania;
Type age (chronostrat): Middle Eocene, Lower Lutetian, Zone P.11 (Globigerapsis kugleri zone).
Type specimens: Holotype PM PF 64595 Paratype PM PF 64593, PM PF 64591, PM PF 64590, PM PF 64594, PM PF 64592
Type repository: London, UK; NHM

Linked specimens: London, UK; NHM (64593) London, UK; NHM (64591) London, UK; NHM (64594) London, UK; NHM (64592) London, UK; NHM (PM PF 64595)

Current identification/main database link: Pearsonites anapetes (Blow 1979)


Original Description
The test is coiled in a low, fairly lax, trochospire with about 18-20 chambers comprising the spire and with 9 chambers present in the final convolution of the test. The dorsal side of the test is sensibly flat and the dorsal sides of the chambers are not inflated. The ventral side of the test is vaulted so that in axial profile the test is virtually plano-convex. The dorsal intercameral sutures of the last whorl of chambers are proximally nearly radial but become retrorse towards the periphery; the intercameral sutures show neither limbation nor pseudolimbation but are slightly incised. Ventrally, the intercameral sutures are uniformly radial, moderately incised, especially for the last few chambers of the last convolution. The earlier chambers of the last convolution in ventral aspect are not inflated but the later chambers become slightly ventrally inflated. Dorsally the chambers are about as equally radially broad as they are tangentially long, but ventrally the chambers of the last convolution are cuneiform with distinct umbilical shoulders. For at least the last convolution of the test, the chambers do not increase rapidly in size so that the equatorial profile is sub-circular in outline.
 'The virtually plano-convex axial profile is not marked by an acute peripheral margin but is gently rounded to sub-acute. There is no marked concentration of muricae over the peripheral margin but the muricae are more densely arranged over the ventral surfaces of the later chambers of the final whorl especially. The umbilicus is deep and widely open so that the relict apertures of most of the chambers of the final convolution open directly into it. The primary aperture of the final chamber is interiomarginal, umbilical-extraumbilical but does not extend greatly towards the peripheral margin so that, because of the widely open umbilicus, there is an approach toward an intraumbilical apertural condition; the aperture possesses a narrow apertural lip which extends posteriorly to be confluent with the broad apertural lips of the relict apertures within the umbilical depression. The wall of the test is composed of calcite, which from other specimens, appears to be arranged in layers of very small microgranules without any geometrical radial arrangement. The wall is perforate with the mural-pores opening between muricae which apparently arise from the confluence and junction of the inter-pore ridges.

Size: Maximum diameter of holotype 0.32 mm.

Extra details from original publication
The paratypes (figs. 1-5) show the generally flat dorsal surface and the widely open umbilicus characteristic for the taxon. The aperture shows a distinct approach to an intraumbilical condition which seems to be a general feature frequently seen in the end-members of many globorotaliid lineages. Globorotalia (Acarinina) broedermanni anapetes differs from G. (A.) broedermanni broedermanni (see Blow, 1979, op. cit., Part 3, pl. 88, figs. 1-3) in possessing a more widely open umbilicus, a more intraumbilical apertural system, a laxer coiling-mode and a more distinctly planoconvex test. In these features anapetes may be regarded as showing typical morphological trends usually associated with end-members (?phylogerontic) of various globorotaliid lineages. However, in this G. (A.) convexa - G. (A.) Iodoensis - G. (A.) broedermanni lineage, the morphogenetic trends do not proceed so far as to produce a wholly 'globigerinid' (vel muricoglobigerinid in this case) apertural system.

References:

Berggren, W. A., Olsson, R. K. & Premoli Silva, I. (2006a). Taxonomy, biostratigraphy and phylogenetic affinities of Eocene Astrorotalia, Igorina, Planorotalites, and Problematica (Praemurica? lozanoi). In, Pearson, P. N. , Olsson, R. K. , Hemleben, C. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 41(Chap 12): 377-400. gs V O

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs


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Globorotalia (Acarinina) broedermanni anapetes compiled by the pforams@mikrotax project team viewed: 26-11-2020

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