Acarinina africana


Classification: pf_cenozoic -> muricate non-spinose -> Truncorotaloididae -> Acarinina -> Acarinina africana
Sister taxa: A. africana, A. alticonica, A. angulosa, A. aspensis, A. boudreauxi, A. bullbrooki, A. coalingensis, A. collactea, A. cuneicamerata, A. echinata, A. esnaensis, A. esnehensis, A. interposita, A. mcgowrani, A. mckannai, > >>

Taxonomy

Citation: Acarinina africana (El Naggar 1966)
Rank: Species
Basionym: Globorotalia africana
Synonyms:
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:

Short diagnosis: 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.

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.

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]

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

Test 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]

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:Lobatecoiling axis:Lowchamber arrangement:Trochospiralumbilicus:Narrow
edge view:Planoconvexumbilical or test sutures:Strongly depressedspiral sutures:Strongly depressedshell porosity:Finely Perforate: 1-2.5
wall texture:Moderately muricateaperture:Extraumbil.-periphaperture border:Thin lipaccessory apertures:None
periphery:N/Aumb chamber shape:Subtriangularsp chbr shape:Subtriangularperiph margin shape:Subangular
umb depth:Deepdiameter mm:0.3width mm:breadth mm:0.14
final-whorl chambers:4.0-6.0

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 very heavy δ13C and relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

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]

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): within E1 zone (55.81-55.96Ma, top in Ypresian stage). Data source: Eocene Atlas
First occurrence (base): within E1 zone (55.81-55.96Ma, base in Ypresian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Berggren et al. 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 9, p. 261

References:

Berggren, W.A.; Pearson, P.N.; Huber, B.T. & Wade, B.S., (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Acarinina. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Allen Press, Lawrence, Kansas, pp. 257-326.

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, 1413 pp.

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) Geology, supplement 2: 1-291.

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.

Pardo et al 1999 [sorry, not in our bibliography yet]


Acarinina africana compiled by the pforams@mikrotax project team viewed: 29-5-2017

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