pforams@mikrotax - Acarinina alticonica

Citation: Acarinina alticonica Fleisher 1974

Basionym: Acarinina mattseensis alticonica

Synonyms:

Globigerina collactea (Finlay).—Bolli, 1957a:72, pl. 15: figs. 21-23 [G. rex Zone, Guayaguayare well 159, Trinidad].— Bolli, 1957b:162, pl. 35: fig. 18a, b [G. palmerae Zone, Navet Fm., Trinidad]. [Not Finlay, 1939.]
Acarinina mattseensis alticonica Fleisher, 1974: pl. 2: figs. 1-5 [lower Eocene Zone P8, DSDP Site 229, Arabian Sea].
Globorotalia (Acarinina) appressocamerata Blow, 1979:907-908, pl. 144: figs. 2, 4-9 (7=holotype) [Zone P8b, DSDP Hole 20C, South Atlantic Ocean].
Globorotalia (Acarinina) cf. appressocamerata Blow, 1979:907-908, pl. 144: figs. 1, 3 [Zone P8b, DSDP Hole 20C, South Atlantic Ocean].
Acarinina appressocamerata Blow.—Lu and Keller, 1995: pl. 3: figs. 9, 10 [Zone P7, DSDP Site 577, Shatsky Rise, north-west Pacific Ocean].

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]

Distinguishing features:
Parent taxon (Acarinina): Moderate to low trochospire; chambers ovoid, usually 4-6 in final whorl.
Wall muricate with pustules on umbilical shoulders;
This taxon: High trochospiral test with closely appressed, angular chambers; strongly muricate

Description

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]

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]

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

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]

Biogeography and Palaeobiology

Caribbean, South Atlantic, Tethys (Egypt). [Berggren et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Berggren et al. (2006b)

No data available. [Berggren et al. 2006]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts; based on comparison with other species of the genus.

Probably descended from A. soldadoensis and ancestral to A. pseudosubsphaerica n. sp. [Berggren et al. 2006]

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

Primary source for this page: Berggren et al. 2006 - Eocene Atlas, chap. 9, p. 262

References:

Berggren, W. A., Kent, D. V., Swisher, I. , C. C. & Aubry, M. -P. (1995b). A revised Cenozoic geochronology and chronostratigraphy. In, Berggren, W. A., Kent, D. V., Aubry, M. -P. & Hardenbol, J. (eds) Geochronology, Time Scales and Global Stratigraphic Correlations. SEPM (Society for Sedimentary Geology) Special Publication No. 54, 129-212. gs

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. Palaeogeography Palaeoclimatology Palaeoecology. 159(1): 1-51. 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 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. (1957b). Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I. 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: 97-123. gs

Bolli, H. M. (1957a). Planktonic foraminifera from the Eocene Navet and San Fernando formations 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: 155-172. gs

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

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 O

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. gs

Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. (85): 1-252. gs

test outline:	Subcircular	chamber arrangement:	Trochospiral	edge view:	Equally biconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Inflated	coiling axis:	Moderate-high	periphery:	N/A	aperture border:	Thin lip
umb chbr shape:	Inflated	umbilicus:	Narrow	periph margin shape:	Broadly rounded	accessory apertures:	None
spiral sutures:	Strongly depressed	umb depth:	Deep	wall texture:	Coarsely muricate	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Strongly depressed	final-whorl chambers:	4.5-5.5	N.B. These characters are used for advanced search. N/A - not applicable

Acarinina alticonica

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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