pforams@mikrotax - Acarinina africana

pforams@mikrotax - Acarinina africana pforams@mikrotax - Acarinina africana

Acarinina africana

Classification: pf_cenozoic -> Truncorotaloididae -> Acarinina -> Acarinina africana
Sister taxa: A. aquiensis ⟩⟨ A. medizzai, A. collactea, A. pentacamerata, A. aspensis, A. interposita, A. echinata, A. pseudosubsphaerica, A. alticonica, A. soldadoensis, A. cuneicamerata, A. angulosa, A. africana, A. sibaiyaensis, A. esnehensis, A. mckannai, A. subsphaerica ⟩⟨ A. bullbrooki, A. punctocarinata, A. boudreauxi, A. rohri, A. topilensis, A. praetopilensis, A. mcgowrani, A. quetra, A. pseudotopilensis, A. wilcoxensis, A. esnaensis> >>

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Taxonomy

Citation: Acarinina africana (El Naggar 1966)

Taxonomic rank: species

Basionym: Globorotalia africana

Synonyms:

Globorotalia africana El Naggar, 1966:193-194, pl. 23: figs. 4a-c [G. aequa / G. esnaensis Subzone, G. velascoensis Zone, Gebel Owaina, Egypt].
Morozovella africana (El Naggar).—Kelly and others, 1998:158-159, fig. 5D [upper Zone P5, from within carbon isotope excursion of late Paleocene Thermal Maximum, ODP Hole 865C, Allison Guyot, central equatorial Pacific Ocean].
Not Globorotalia (Morozovella) africana El Naggar.—Blow, 1979:983, pl. 104: figs. 7-10.
Not Acarinina aff. africana (El Naggar).—Pardo and others, 1999:44, pl. 2: figs. 13-14.

Taxonomic discussion: Acarinina africana is a very distinctive and short-lived taxon that is characteristic of the Paleocene-Eocene Thermal Maximum (PETM) event (Kelly and others, 1998). [Berggren et al. 2006]

Catalog entries: Globorotalia africana

Type images:

holotype: G. africana
holotype: G. africana

Distinguishing features:
Parent taxon (Acarinina): Moderate to low trochospire; chambers ovoid, usually 4-6 in final whorl.
Wall muricate with pustules on umbilical shoulders;
This taxon: Like A. sibaiyaensis but with axially-compressed test, strongly lobulate peripheral margin, and chambers change ontogenetically from globular to more lenticular shapes.

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
They are being edited as the site is developed and comments on them are especially welcome.

Description

Diagnostic characters:

Acarinina africana is distinguished from A. sibaiyaensis by its axially-compressed test, strongly lobulate peripheral margin, and manner in which its chambers change ontogenetically from globular to more lenticular shapes. [Berggren et al. 2006]

Morphology:

Peripheral outline oval, elongate, strongly lobulate; weakly planoconvex to biconvex; test axially compressed; peripheral margin acutely pinched, occasionally with weak muricate keel; chambers triangular on both umbilical and spiral sides; low trochospiral; approximately 10-12 chambers arranged in approximately 3 whorls; chambers vary ontogenetically, with early chambers globular to subconical and later chambers more lenticular, strongly compressed; moderate rate of chamber expansion; sutures gently curved, radial, slightly raised to depressed; primary aperture a low umbilical-extraumbilical arch extending to peripheral margin, sometimes with faint lip; typically 4-6 chambers in final whorl; umbilicus narrow. [Berggren et al. 2006]

Wall type:

Muricate, normal perforate, nonspinose. [Berggren et al. 2006]

Size:

Diminutive, typically <0.20 mm; holotype dimensions: maximum diameter: 0.30 mm; minimum diameter: 0.20 mm; thickness: 0.14 mm (last chamber) (El Naggar, 1966, p. 194). [Berggren et al. 2006]

Character matrix
test outline: Lobate chamber arrangement: Trochospiral edge view: Equally biconvex aperture: Umbilical-extraumbilical
sp chamber shape: Subtriangular coiling axis: Very low periphery: N/A aperture border: Thin lip
umb chbr shape: Subtriangular umbilicus: Narrow periph margin shape: Subangular accessory apertures: None
spiral sutures: Strongly depressed umb depth: Deep wall texture: Moderately muricate shell porosity: Finely Perforate: 1-2.5µm
umbilical or test sutures: Strongly depressed final-whorl chambers: 4-6 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Ranges from tropical to temperate regions; central equatorial Pacific (ODP Site 865), New Jersey Coastal Plain (Bass River),
Tethyan deposits of northern Africa (Egypt) and probable occurrences in Spain (Alamedilla). [Berggren et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Berggren et al. (2006b)

Isotope paleobiology

Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts; based on comparison with other species of the genus.

Phylogenetic relations

This species is closely related to A. sibaiyaensis and was probably derived from A. esnehensis via A. sibaiyaensis during the period of intense environmental stress associated with the PETM event. [Berggren et al. 2006]

Most likely ancestor: Acarinina sibaiyaensis - at confidence level 4 (out of 5). Data source: Berggren et al. (2006) fig9.2.

Biostratigraphic distribution

Geological Range:
Notes: Restricted to Zone E1, most commonly found within carbon isotope excursion interval of the PETM, although rare specimens (?reworked) have been observed at stratigraphically higher horizons (Kelly and others, 1998). [Berggren et al. 2006]
Last occurrence (top): at top of E1 zone (100% up, 55.8Ma, in Ypresian stage). Data source: Eocene Atlas
First occurrence (base): at base of E1 zone (0% up, 56Ma, in Thanetian stage). Data source: Eocene Atlas

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Taxon plotted: Acarinina africana, synonyms included - Acarinina africana; Globigerinita africana;
See also space-time plot :: Samples map :: Parent: Acarinina

Primary source for this page: Berggren et al. 2006 - Eocene Atlas, chap. 9, p. 261

References:

Berggren, W. A., Pearson, P. N., Huber, B. T. & Wade, B. S. (2006b). Taxonomy, biostratigraphy, and phylogeny of Eocene Acarinina. 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 9): 257-326. gs 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

El-Naggar, Z. R. (1966). Stratigraphy and planktonic foraminifera of the Upper Cretaceous-Lower Tertiary succession in the Esna-Idfu region, Nile Valley, Egypt, U. A. R. Bulletin of the British Museum (Natural History). supplement 2: 1-291. gs

Kelly, D. C., Bralower, T. J. & Zachos, J. C. (1998). Evolutionary consequences of the latest Paleocene thermal maximum for tropical planktonic foraminifera. Palaeogeography Palaeoclimatology Palaeoecology. 141: 139-161. gs

Pardo, A., Adatte, T., Keller, G. & Oberhänsli, H. (1999). Paleoenvironmental changes across the Cretaceous-Tertiary boundary at Koshak, Kazakhstan, based on planktic foraminifera and clay mineralogy. Palaeogeography Palaeoclimatology Palaeoecology. 154: 247-273. gs

Acarinina africana compiled by the pforams@mikrotax project team viewed: 25-4-2025

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test outline:	Lobate	chamber arrangement:	Trochospiral	edge view:	Equally biconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Subtriangular	coiling axis:	Very low	periphery:	N/A	aperture border:	Thin lip
umb chbr shape:	Subtriangular	umbilicus:	Narrow	periph margin shape:	Subangular	accessory apertures:	None
spiral sutures:	Strongly depressed	umb depth:	Deep	wall texture:	Moderately muricate	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Strongly depressed	final-whorl chambers:	4-6	N.B. These characters are used for advanced search. N/A - not applicable