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Acarinina alticonica Fleisher 1974 from: Pearson, P.N.Olsson, R.K.Hemleben, C.Huber, B.T.Berggren, W.A. (2006): Atlas of Eocene Planktonic Foraminifera. p. 1-513
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Anonymous: Unedited TaxonConcept data
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Species Acarinina alticonica Fleisher 1974


Diagnosis / Definition:
Pearson et al. (2006):
DESCRIPTION. Type of wall: Densely muricate, particularly around umbilicus. 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 2 1/2 whorls; intercameral sutures weakly curved and incised; chambers rounded in edge view. Size: Maximum diameter of holotype of A. alticonica: 0.3 1 mm; axial elevation: 0.30 mm (Fleisher, 1974, p. 10 13); Maximum diameter of holotype of A. appressocamerata: 0.37 mm (Blow, 1979, p. 907)
Discussion / Comments:
Pearson et al. (2006):
DISTINGUISHlNG FEATURES.- 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. 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 jormosa, M. lens formis, M. subbotinae, among others). Fleisher 'S (1 974) 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. PHYLOGENETIC RELATION SHIPS .- Probably descended from A. soldadoensis and ancestral to A. pseudosubsphaerica n. sp. STRATIGRAPHIC DISTRIBUTION.- Zone E4-E7. GEOGRAPHIC DISTRIBUTION.- Caribbean, South Atlantic, Tethys (Egypt). STABLE ISOTOPE PALEOB1OLOGY.- No data available.
Systematics:

35
 Ordo Foraminiferida
  Superfamilia Globigerinaceae
   Familia Truncorotaloididae
    Genus Acarinina
     Species Acarinina alticonica
Synonym list:
Pearson et al. (2006):
1957 Globigerina collactea Finlay. - Bolli : p.72 pl. 15; fig. 21-23 [G. rex Zone, Guayaguayare well 159, Trinidad]
1974 Acarinina mattseensis alticonica Fleisher. - Fleisher : pl. 2; fig. 1-5 [lower Eocene Zone P8, DSDP Site 229,Arabian Sea]
1979 Globorotalia (Acarinina) appressocamerata Blow. - Blow : p. 907-908 pl. 144; fig. 2, 4-9 (7=holotype) [Zone P8b, DSDP Hole 20C, South Atlantic Ocean]
1979 Globorotalia (Acarinina) aff. appressocamerata Blow. - Blow : p. 907-908 pl. 144; fig. 1, 3 [Zone P8b, DSDP Hole 20C, South Atlantic Occan]
1995 Acarinina appressocamerata Blow. - Lu & Keller : pl. 3; fig. 9, 10 [Zone P7, DSDP Site 577, Shatsky Rise, north-west Pacific Ocean]
2006 Acarinina alticonica Fleisher. - Pearson et al. : p.267 pl. 9.2; fig. 1-8 (Pl. 9.2, Figs. 1-3: reillustration of holotype of Acarinina mattseensis alticonica Fleisher) (Pl. 9.2, Figs. 4-8: reillustration of holotype and paratypes of Globorotalia (Acarinina) appressocamerata Blow)
Specimen:
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 211525
References:

Bolli,H.M. (1957):
The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad, B.W.I . Bulletin of the U.S. National Museum Vol. 215 p. 61-82

Fleisher,R.L. (1974):
Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A.
In: Initial Reports of the Deep Sea Drilling Project Vol. 23 Eds: Whitmarsh, R.B.Weser, O.E.Ross, D.A. p. 1001-1072

Blow,W.H. (1979):
The Cainozoic Globigerinida. 3 Vols p. 1413 pp

Lu,G. and Keller,G. (1995):
Planktic Foraminiferal Faunal Turnovers in the Subtropical Pacific during the Late Paleocene to Early Eocene . Journal of Foraminiferal Research Vol. 25 p. 97-116

Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006):
Atlas of Eocene Planktonic Foraminifera. p. 1-513
Anonymous: Unedited TaxonConcept data
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