Acarinina alticonica


Classification: pf_cenozoic -> muricate non-spinose -> Truncorotaloididae -> Acarinina -> Acarinina alticonica
Sister taxa: A. medizzai, A. collactea, A. pentacamerata, A. aspensis, A. echinata, A. pseudosubsphaerica, A. alticonica, A. soldadoensis, A. interposita, A. cuneicamerata, A. angulosa, A. africana, A. sibaiyaensis, A. esnehensis, A. mckannai, A. subsphaerica, A. bullbrooki, A. punctocarinata, A. boudreauxi, A. rohri, A. topilensis, > >>

Taxonomy

Citation: Acarinina alticonica Fleisher 1974
Rank: Species
Basionym: Acarinina mattseensis alticonica
Synonyms:
Taxonomic discussion: This is a distinct early Eocene acarininid with superficial resemblance to the (predominantly) Paleocene morphotype Acarinina subsphaerica (Shutskaya). Blow (1979, p. 907) drew attention to these similarities in describing his new species Acarinina appressocamerata but observed that appressocamerata differed from subsphaerica in having more angulate chambers on the umbilical side and a more sharply delimited, more open, quadrate-shaped umbilicus (compared to the more rounded chambers and more restricted umbilicus in subsphaerica). Blow (1979, p. 908) also observed the lack of stratigraphic overlap between these two forms. Acarinina subsphaerica is abundant in Zone P4, and its last common occurrence in tropical sites has been used to subdivide Zone P4 (Berggren and others, 1995), although it may range higher in higher latitudes (Olsson and others, 1999, Berggren and others, 2000). Our detailed studies in Egypt have shown A. alticonica to appear in mid-Zone E4, a little lower than recorded by Blow (1979, p. 908). It forms a distinct component of early Eocene faunas (together with A. interposita, A. pentacamerata, A. soldadoensis, Morozovella formosa, M. lensiformis, M. subbotinae, among others).
Fleisher’s (1974) species Acarinina mattseensis alticonica, which he described as having a restricted range in Zone P8 (=E6) in the Arabian Sea, appears to be a prior synonym exhibiting the same morphologic characters recorded by Blow (1979) in describing appressocamerata. While Fleisher drew attention to superficial resemblance of his taxon with Subbotina senni, he firmly rejected any affinity between the two forms. [Berggren et al. 2006]

Catalog entries: Acarinina mattseensis alticonica;

Type images:

Short diagnosis: This form is distinguished by its strongly muricate test with a high trochospire and closely appressed, angular chambers. It is distinguished from A. subsphaerica and A. pseudosubsphaerica n. sp. by having more compressed, angular chambers and a less high-spired test.

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 form is distinguished by its strongly muricate test with a high trochospire and closely appressed, angular chambers. It is distinguished from A. subsphaerica and A. pseudosubsphaerica n. sp. by having more compressed, angular chambers and a less high-spired test. [Berggren et al. 2006]

Wall type: Densely muricate, particularly around umbilicus. [Berggren et al. 2006]

Test morphology: Medium to high trochospiral, biconvex to subspherical, weakly lobulate test; circular outline, rounded periphery in edge view; in umbilical view equatorial profile slightly lobate, 5 moderately inflated, embracing, appressed, angulate chambers in last whorl, gradually increasing in size, tightly coiled around relatively narrow, deep umbilicus which is bordered by circumumbilical coalescence of prominent muricae; intercameral sutures radial, weakly incised; aperture a low arched, umbilical-extraumbilical slit bordered by distinct lip; on spiral side 11-12 chambers, tangentially longer than radially broad, coiled in 2½ whorls; intercameral sutures weakly curved and incised; chambers rounded in edge view. [Berggren et al. 2006]

Size: Maximum diameter of holotype of A. alticonica: 0.31 mm; axial elevation: 0.30 mm (Fleisher, 1974, p. 1013); Maximum diameter of holotype of A. appressocamerata: 0.37 mm (Blow, 1979, p. 907) [Berggren et al. 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Equally biconvexaperture:
umb chamber shape:Inflatedcoiling axis:Moderate-highperiphery:N/Aaperture border:Thin lip
sp chbr shape:Inflatedumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
umbilical or test sutures:Strongly depressedumb depth:Deepwall texture:Coarsely muricateshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:Strongly depresseddiameter mm:0.31width mm:breadth mm:0.3
final-whorl chambers:4.5-5.5

Biogeography and Palaeobiology


Geographic distribution: Caribbean, South Atlantic, Tethys (Egypt). [Berggren et al. 2006]
Aze et al. 2011 summary: Low to middle 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: Probably descended from A. soldadoensis and ancestral to A. pseudosubsphaerica n. sp. [Berggren et al. 2006]

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

Biostratigraphic distribution

Geological Range:
Notes: Zone E4-E7. [Berggren et al. 2006]
Last occurrence (top): within E7 zone (45.72-50.20Ma, top in Lutetian stage). Data source: Eocene Atlas
First occurrence (base): in mid part of E4 zone (50% up, 53.6Ma, 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. 262

References:

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.

Berggren, W.A.; Van Fossen, M.; V., K.D.; Norris, R.D. & Quillévéré, F., (2000). Integrated Paleocene calcareous plankton magnetobiochronology and stable isotope stratigraphy: DSDP Site 384 (NW Atlantic Ocean): , v. 159, p. 1-51. Paleogeography Palaeoclimatology Palaeoecology, 159(1): 1-51.

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.

Bolli, H.M., (1957). Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera: U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, DC, pp. 97-123.

Bolli, H.M., (1957). Planktonic foraminifera from the Eocene Navet and San Fernando formations of Trinidad. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera: U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, D.C., pp. 155-172.

Finlay, H.J., (1939). New Zealand foraminifera: Key species in stratigraphy - no. 2. Transactions of the Royal Society of New Zealand, 69(1): 89-128.

Fleisher, R.L., (1974). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project, 23: 1001-1072.

Lu, G. & Keller, G., (1995). Planktic foraminiferal faunal turnovers in the subtropical Pacific during the Late Paleocene to Early Eocene. Journal of Foraminiferal Research, 25: 97-116.

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.


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Acarinina alticonica compiled by the pforams@mikrotax project team viewed: 19-11-2017

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