resemblance (in some instances) to the stratigraphically younger (middle Eocene) A. topilensis. [Berggren et al. 2006]
Catalog entries: Globorotalia quetra
Type images:Distinguishing features: Like A. pseudotopilensis but with angular test; chambers loosely disposed to each other at ~ 90°; and with a distinct, but discontinuous, peripheral muricocarina.
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.
Wall type: Moderately to strongly muricate with concentration of muricae along peripheral margin of last whorl, nonspinose, normal perforate. [Berggren et al. 2006]
Morphology: Low trochospiral; test subquadrate, planoconvex; peripheral margin lobulate; chambers on umbilical side moderately inflated, flattened on spiral side; 4 broadly subtriangular chambers visible in umbilical view; anterior and posterior margins of last chamber flattened resulting in disjunct geometry with bordering chambers and conical apex of last chamber; sutures depressed/incised, curved to sinuous, radial; umbilicus relatively wide, deep; aperture an umbilical-extraumbilical, arch extending towards (but not to) the peripheral margin; 10-12 chambers in 2½ to 3 whorls on spiral side; chambers loosely disposed, meeting almost at right angles, increasing gradually in size; final chamber sometimes reduced in size; chambers lens-shaped, tangentially longer than radially broad in general, overlapping; sutures curved; discrete intercameral openings visible on some individuals (depending on preservation); planoconvex in edge view, final chamber distinctly anguloconical with high conical angle; periphery distinctly, but discontinuously, muricocarinate [Berggren et al. 2006]
Size: Maximum diameter of holotype 0.50 mm, thickness 0.38 mm. [Berggren et al. 2006]
Character matrix
test outline: | Subquadrate | chamber arrangement: | Trochospiral | edge view: | Planoconvex | aperture: | Umbilical-extraumbilical |
sp chamber shape: | Inflated | coiling axis: | Very low | periphery: | N/A | aperture border: | N/A |
umb chbr shape: | Inflated | umbilicus: | Wide | periph margin shape: | Broadly rounded | accessory apertures: | Sutural |
spiral sutures: | Moderately depressed | umb depth: | Deep | wall texture: | Coarsely muricate | shell porosity: | Finely Perforate: 1-2.5µm |
umbilical or test sutures: | Moderately depressed | final-whorl chambers: | 4.0-4.0 | N.B. These characters are used for advanced search. N/A - not applicable |
Geographic distribution: Widely distributed in (sub)tropical regions (Caribbean, Atlantic, Indo-Pacific, Tethyan/Mediterranean regions, North Caucasus) [Berggren et al. 2006]
Aze et al. 2011 summary: Low latitudes; based on Berggren et al. (2006b)
Isotope paleobiology: No data available [Berggren et al. 2006]
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: Descended from A. pseudotopilensis. [Berggren et al. 2006]
Most likely ancestor: Acarinina pseudotopilensis - at confidence level 4 (out of 5). Data source: Berggren et al. (2006) fig9.2.
Geological Range:
Notes: Zone E3 (upper part) to Zone E6. [Berggren et al. 2006]
Last occurrence (top): within E6 zone (50.20-50.67Ma, top in Ypresian stage). Data source: Eocene Atlas
First occurrence (base): in upper part of E3 zone (80% up, 54.7Ma, in Ypresian stage). Data source: Eocene Atlas
Plot of occurrence data:
Primary source for this page: Berggren et al. 2006 - Eocene Atlas, chap. 9, p. 310
Berggren, W. A. (1977a). Atlas of Palaeogene Planktonic Foraminifera: some Species of the Genera Subbotina, Planorotalites, Morozovella, Acarinina and Truncorotaloides. In, Ramsay, A. T. S. (ed.) Oceanic Micropaleontology. Academic Press, London 205-300. gs 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 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 Bolli, H. M. (1957d). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 61-82. gs V O Fleisher, R. L. (1974a). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project. 23: 1001-1072. gs V O Hillebrandt, A. , von (1962). Das Paleozän und seine Foraminiferenfauna im Becken von Reichenhall und Salzburg. Abhandlungen Bayerischen Akademie der Wissenschaften, Mathematisch-Naturwissenschaftliche Klasse, Neue Folge. 108: 1-182. gs Snyder, S. W. & Waters, V. J. (1985). Cenozoic planktonic foraminiferal biostratigraphy of the Goban Spur Region, Deep Sea Drilling Project Leg 80. Initial Reports of the Deep Sea Drilling Project. 80: 439-472. gs Stainforth, R. M., Lamb, J. L., Luterbacher, H., Beard, J. H. & Jeffords, R. M. (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. University of Kansas Paleontological Contributions, Articles. 62: 1-425. gs V O Warraich, M. Y. & Ogasawara, K. (2001). Tethyan Paleocene-Eocene planktic foraminifera from the Rakhi Nala and Zinda Pir land sections of the Sulaiman Range, Pakistan. Science Reports of the Institute of Geosciences, University of Tsukuba, Section B Geological Sciences. 22: 1-59. gs Warraich, M. Y., Ogasawara, K. & Nishi, H. (2000). Late Paleocene to early Eocene planktic foraminiferal blostratigraphy of the Dungan Formation, Sulaiman Range, central Pakistan. Paleontological Research, Tokyo. 4(4): 275-301, 218 figures, 273 aendices. gsReferences:
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Acarinina quetra compiled by the pforams@mikrotax project team viewed: 22-1-2021
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