Acarinina subsphaerica


Classification: pf_cenozoic -> muricate non-spinose -> Truncorotaloididae -> Acarinina -> Acarinina subsphaerica
Sister taxa: << < A. mcgowrani, A. mckannai, A. medizzai, A. nitida, A. pentacamerata, A. praetopilensis, A. primitiva, A. pseudosubsphaerica, A. pseudotopilensis, A. punctocarinata, A. quetra, A. rohri, A. sibaiyaensis, A. soldadoensis, A. strabocella, A. subsphaerica, A. topilensis, A. wilcoxensis,

Taxonomy

Citation: Acarinina subsphaerica (Subbotina 1947)
Rank: Species
Basionym: Globigerina subsphaerica
Synonyms:
Taxonomic discussion: The strongly conical spire and small, tightly coiled muricate test makes this one of the most distinctive taxa of the middle Paleocene. Yet it remains one of the least understood taxa among the acarininids. Although Subbotina described subsphaerica as resembling "a slightly bursting chestnut" (1947:108), she also indicated that the test is "reticulate, finely porous," but she made no mention of its most distinctive character: its high conical spire. In fact, Subbotina (1953:53) retained subsphaerica among her "polythalamous species of Globigerina" characterized by possessing five or more closely packed chambers in the last whorl (together with such taxa as edita Subbotina, compressa Plummer, pseudobulloides Plummer, postcretacea Mjatliuk, and tarchanensis Subbotina and Chutzieva). This oversight is difficult to comprehend and may be partly ascribed to the poor state of preservation (recrystallized tests) of most northern Caucasus Paleocene material. It remained for Shutskaya (1958) to
provide the first adequate characterization of this taxon, to clearly illustrate the high degree of variability in this taxon (Shutskaya, 1958, 1970a), in particular, its distinctive high spire, and to transfer it to its appropriate home in the genus Acarinina. In fact, Morozova (1958, fig. 5), in a paper dealing with the morphologic characters important in the classification of Paleogene taxa of the Globigerinidea, observed that the microspheric generation among "globigerinids" typically possess a higher spire and more whorls of chambers than megalospheric forms, and she cited Globigerina subsphaerica Subbotina as a good illustration of this feature.
This taxon has been considered a junior synonym of Acarinina mckannai (White) by some workers (Hillebrandt, 1962; Krasheninnikov and Ponikarov, 1965; Stainforth et al., 1975; Berggren, 1977) because of their supposed similarity. The latter is distinguished by its significantly larger test, relatively low spire, and more evolute coiling pattern resulting in a wide and open umbilicus. In our material, A. mckannai stratigraphically appears somewhat higher/later than A. subsphaerica from which we suggest it is descended (cf. Stainforth
etal., 1975).
We note that moderately to high-spired morphotypes with
surficial morphology/ornament comparable to A. subsphaerica occur in upper lower to lower middle Eocene; these may represent a continuation of the late Paleocene acarininid radiation or an independent early Eocene radiation. This issue, however, is beyond the scope of this study. Similar high-spired acarinids, which we regard as synonymous with A. subsphaerica, have been described from middle Paleocene deposits in Azerbaizhan, Tadzhikistan, and the Crimea. These include Globoconusa quadripartitaformis Khalilov (1956), Acarinina falsospiralis Davidzon and Morozova (1964), and Acarinina microsphaerica Morozova (1967). Globigerina chascanona Loeblich and Tappan (1957a) is a small, very high-spired pustulose form, which we regard as an immature stage of A. subsphaerica. Both Blow (1979) and Huber (1991b) noted these small forms, which they placed in chascanona. Larger (adult) forms of A. subsphaerica have been identified in middle Paleocene coastal plain deposits from Alabama and New Jersey by Loeblich and Tappan as Globigerina spiralis Bolli. [Olsson et al. 1999]

Catalog entries: Globigerina chascanona;
Globigerina subsphaerica;

Type images:

Short diagnosis: This species is characterized by its strongly elevated spire and the tightly coiled, small test which gives it a sphaerical, globular shape. The umbilicus is narrow and deep and is surrounded by coarse pustules (muricae). Specimens usually have a diminutive final chamber with an arched aperture.

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: This species is characterized by its strongly elevated spire and the tightly coiled, small test which gives it a sphaerical, globular shape. The umbilicus is narrow and deep and is surrounded by coarse pustules (muricae). Specimens usually have a diminutive final chamber with an arched aperture. [Olsson et al. 1999]

Character matrix

test outline:Lobatecoiling axis:Lowchamber arrangement:Trochospiralumbilicus:Narrow
edge view:Inequally biconvexumbilical or test sutures:Moderately depressedspiral sutures:Moderately depressedshell porosity:-
wall texture:Finely muricateaperture:Umbilicalaperture border:N/Aaccessory apertures:None
periphery:N/Aumb chamber shape:Subtriangularsp chbr shape:Trapezoidalperiph margin shape:Broadly rounded
umb depth:Deepdiameter mm:0.27width mm:0.25breadth mm:-
final-whorl chambers:5.0-6.0

Biogeography and Palaeobiology


Geographic distribution: This species appears global in distribution in spite of an apparent bias to a Tethyan distribution, which is probably related to numerous citations in the Russian literature (Figure 22). [Olsson et al. 1999]
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (1999)

Isotope paleobiology: No data available. [Olsson et al. 1999]
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: Acarinina subsphaerica evolved from A. nitida by an increase in spire height and the development of a coarsely muricate umbilical surface, which is a feature characteristic of all subsequent acarininids. Both A. subsphaerica and A. nitida share an anguloconic, umbilically inflated test as juveniles and, in many of the geologically older examples, a flat or gently domed spiral surface. Acarinina subsphaerica gave rise to A. mckannai by an increase in whorl expansion rate. [Olsson et al. 1999]

Biostratigraphic distribution

Geological Range:
Notes: Subzone P4a. We have not found A. subsphaerica associated with P3b faunas in any of our material nor have we found it to occur above the middle part of Zone P4 at low latitudes. Indeed, it is the short and distinct stratigraphic range of this taxon that renders it so useful for subdivision of Zone P4. We recognize high-spired acarininids from the upper Paleocene at the high southern latitude ODP Site 690. (This taxon was recently recorded by Lu and Keller (1995) in younger stratigraphic levels at DSDP Site 577 (Shatsky Rise), northwestern Pacific Ocean and by Huber (1991b) at ODP Site 738, southwestern Kerguelen Plateau (southern Indian Ocean) near the Paleocene/Eocene boundary.) [Olsson et al. 1999]
Last occurrence (top): within P4b subzone (57.79-60.52Ma, top in Thanetian stage). Data source: Olsson et al. 1999
First occurrence (base): within P4a subzone (60.52-60.73Ma, base in Selandian stage). Data source: Olsson et al. 1999

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 52

References:

Berggren, W.A. & Norris, R.D., (1997). Biostratigraphy, phylogeny and systematics of Paleocene trochospiral planktonic foraminifera. Micropaleontology, Supplement 1, 43: 1-116.

Berggren, W.A., (1977). Atlas of Palaeogene Planktonic Foraminifera: some Species of the Genera Subbotina, Planorotalites, Morozovella, Acarinina and Truncorotaloides. In: Ramsay, A.T.S. (Editor), Oceanic Micropaleontology. Academic Press, London, pp. 205-300.

Berggren, W.A.; Kent, D.V.; Swisher, I., C.C. & Aubry, M.-P., (1995). A revised Cenozoic geochronology and chronostratigraphy. In: Berggren, W.A. et al. (Editors), Geochronology, Time Scales and Global Stratigraphic Correlations. SEPM (Society for Sedimentary Geology) Special Publication No. 54.

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.

Hillebrandt, A., (1962). Das paleozan und seine Foraminiferenfauna im Becken von Reichehall und Salzburg. Abhandlungen Bayerische Akademie der Wissenschaften Mathematisch Naturwissenschaftliche Klasse, 108: 1-182.

Krasheninnikov & Ponikarov 1965 [sorry, not in our bibliography yet]

Morozova, V.G., (1958). K sistematike i morfologii paleogenovykh predstavitelei nadsemeistva Globigerinidea [Addition to the systematics and morphology of the Paleogene members of the Superfamily Globigerinidea]. Voprosy Mikropaleontologii, 114: 22-52.

Olsson, R.K.; Hemleben, C.; Berggren, W.A. & Huber, B.T., (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Contributions to Paleobiology. Smithsonian Institution Press, Washington, DC, 1-252 pp.

Shutskaya, E.K., (1958). Variability in some lower Paleogene planktonic foraminifera from the northern Caucasus. Voprosy Mikropal, Moscow, 1958(2): 86.

Stainforth, R.M.; Lamb, J.L.; Luterbacher, H.; Beard, J.H. & Jeffords, R.M., (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. The University of Kansas Paleontological Contributions, 62: 1-425.

Subbotina, N.N., (1947). Danian and Paleogene foraminifera of the northern Caucasus. Vses Neft Nauchno-Issled . Geol . -Razved . Inst. (VNIGRI) [All-Union Petroleum Scientific Research Geological Prospecting Institute], Microfauna of the oilfields of the Caucasus, Emba, and Central Asia, 1947: 39-160.

Subbotina, N., (1953). Foraminiferes fossiles d'URSS Globigerinidae, Globorotaliidae, Hantkeninidae. Bureau de Recherches Geologiques et Minieres, 2239: 1-144.


Acarinina subsphaerica compiled by the pforams@mikrotax project team viewed: 23-5-2017

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