Acarinina africana Naggar 1966 from: Pearson, P.N.Olsson, R.K.Hemleben, C.Huber, B.T.Berggren, W.A. (2006): Atlas of Eocene Planktonic Foraminifera. p. 1-513 . |
Notice: This catalogue page may contain unedited data.
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Species Acarinina africana Naggar 1966 |
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Diagnosis / Definition: |
Pearson et al. (2006):
DESCRIPTION.
Type of wall: Muricate, normal perforate,
nonspinose.
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.
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). |
Discussion / Comments: |
Pearson et al. (2006):
DISTINGUISHING FEATURES.-
Acarinina africana
is distinguished from A. sihaiyaensis by its axially compressed
test, strongly lobulate peripheral margin, and
manner in which its chambers change ontogenetically
from globular to more lenticular shapes.
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).
PHYLOGENETIC RELATIONSHIPS.-
This species
is closely related to A. sibaiyaensis and was probably
derived from A. esnehensis via A. sihaiyaensis during
the period of intense environmental stress associated with
the PETM event.
STRATIGRAPHIC RANGE.-
Restricted to Zone El,
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).
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).
STABLE ISOTOPE PALEOBIOL0GY.-
No data
available. |
Systematics: |
35 Ordo Foraminiferida
Superfamilia Globigerinaceae
Familia Truncorotaloididae
Genus Acarinina
Species Acarinina africana
Species Acarinina boudreauxi
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Synonym list: |
Pearson et al. (2006):
1966 Globorotalia africana El Naggar. - El-Naggar : p. 193-194 pl. 23; fig. 4a-c [G. aequa / G. esnaensis Subzone, G. velascoensis
Zone, Gebel Owaina, Egypt]
1998 Morozovella africana El Naggar. - Kelly et al. : p. 158-159 fig. 5D [upper Zone P5, from within
carbon isotope excursion of late Paleocene Thermal
Maximum, ODP Holc 865C, Allison Guyot, central
equatorial Pacific Ocean]
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Specimen: |
Natural History Museum, London, Inventory number: USNM 494823
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References: |
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. . Bull. Br. Mus. nat. Hist. ser. Geol. Vol. 2 p. 1-291
Blow,W.H. (1979): The Cainozoic Globigerinida. 3 Vols p. 1413 pp
Kelly,.; Bralower,. and Zachos,. (1998): On the demise of the Early Paleogene Movozovella velascoensis lineage: terminal progenesis in the planktonic foraminifera . Palaios Vol. 16 p. 507-523
PARDO,A..; Keller,G. and Oberhansli,H.. (1999): Paleoecologic and paleoceanographic evolution of the Tethyan realm during the Paleocene-Eocene transition . Journal of Foraminiferal Research Vol. 29 p. 37-57
Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006): Atlas of Eocene Planktonic Foraminifera. p. 1-513
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