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Paragloborotalia nana Bolli 1957 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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Species Paragloborotalia nana Bolli 1957



Diagnosis / Definition:
Pearson et al. (2006):
DESCRIPTION. Type of wall: Normal perforate, coarsely cancellate, sacculifer-type, spinose in life, heavy gametogenetic calcification is often present. Test morphology: Test very low trochospiral, globular, quadrate in outline, chambers globular, much inflated, embracing; in spiral view 4, occasionally 41/2 globular, embracing chambers in ultimate whorl, increasing slowly in size, sutures slightly depressed, straight, last 4 chambers make up about three-quarters of the test size, ultimate chamber may be slightly reduced in size; in umbilical view 4, occasionally 41/2 globular, embracing chambers, increasing slowly in size, sutures slightly depressed, straight, forming a cross, umbilicus very small sized, deep opening, sometimes closed off by surrounding chambers, aperture umbilical-extraumbilical, bordered by a narrow, often thickened, continuous, lip, ultimate chamber may be slightly reduced in size; in edge view chambers globular, spiral side flat, periphery rounded, aperture a low arch extending midway onto the peripheral edge, bordered by a thickened lip. Size: Maximum diameter of holotype 0.25 mm, minimum diameter 0.23 mm, maximum width 0.28 mm.
Discussion / Comments:
Chaisson & Leckie (1993):
Remarks: This species is a member of the spinose "opima" group, which is assigned to the genus Paragloborotalia (Spezzaferri, 1991). Bolli and Saunders (1985, p. 206) describe a gradual evolution of "Globorotalia continuosa" from "G. opima nana." Similar species: P. nana differs from P. continuosa in having a lower arched aperture and more embracing chambers.
Pearson et al. (2006):
DTSTTNGUISHING FEATURES.- Paragloborotalia nana is a small species, as the name suggests, and tends to be very conservative in morphology. A prominent lip is always present, which often nearly obscures the primary aperture- Paragloborotalia nana usually has 4 chambers in the final whorl. The slowly enlarging chambers in the final whorl give the test a compact, quadrangular appearance. The tight coiling, much inflated, embracing chambers, and very narrow umbilicus combined with straight radial sutures means that the sutures make out a cross pattern in both spiral and umbilical views in four-chambered specimens. P. nana is distinguished from P griffinoides in having a quadrate-shaped, more compact test. In P. nana, the chambers in the ultimate whorl increase more slowly in size with the ultimate chamber nearly equal in size to the penultimate chamber, thus developing a quadrate shape. PHYLOGENETIC RELATIONSHIPS.- P. nana evolved from P. griffinoides in the middle Eocene by developing more inflated, embracing chambers, and a slower rate of chamber size increase in the ultimate whorl. It was ancestral to P. opima in the Oligocene. GEOGRAPHIC DISTRIBUTION .- Worldwide in the low and mid-latitudes. STABLE ISOTOPE PALEOBIOL0GY.-Douglas and Savin (1978) and Poore and Matthews (1 984) recorded distinctly positive ò18O for th;s species indicating a deep planktonic habitat.
Systematics:

35
 Ordo Foraminiferida
  Superfamilia Globigerinaceae
   Familia Globigerinidae
    Genus Paragloborotalia
     Species Paragloborotalia nana
Synonym list:
Chaisson & Leckie (1993):
1957 Globorotalia opima nana Bolli. - Bolli : p.118 pl. 28; fig. 3a-c
1983 "Globorotalia" nana Bolli. - Kennett & Srinivasan : p.106 pl. 24; fig. 3-5
1993 Paragloborotalia nana Bolli. - Chaisson & Leckie : p.176 pl. 8; fig. 10-11
Pearson et al. (2006):
1957 Globorotalia opima nana Bolli. - Bolli : p.118 pl. 28; fig. 3a-c [Oligocene Globorotalia opima opima Zone, Cipero Fm., Trinidad]
1969 Globorotalia (Turborotalia) opima nana Bolli. - Blow : p.154 pl. 39; fig. 1 [lower Oligocene Zone P20, Cipero Fm., Trinidad]
1977 Globorotalia nana Bolli. - Krasheninnikov & Pflaumann : p.606 pl. 6; fig. 10-11c [Oligocene, DSDP Hole 369A, eastern North Atlantic Ocean]
1978 Globorotalia opima nana Bolli. - Toumarkine : p.714 pl. 8; fig. 3-4 [Oligocene Globorotalia opima opima Zone, DSDP Site 360, southeast Atlantic Ocean]
1985 Globorotalia opima nana Bolli. - Bolli & Saunders : p.202 fig. 26: 16a-c (holotype reillustrated); fig. 26: 15, 17-20 (paratypes) [Oligocene Globorotalia opima opima Zone, Cipero Fm., Trinidad]
1995 Jenkinsella opima nana Bolli. - Poag & Commeau : p.149 pl. 6; fig. 21, 22 [Oligocene, Hammond Well, Maryland]
2004 Paragloborotalia nana Bolli. - Pearson et al. : p.36 pl. 1; fig. 21 [middle Eocene Zone P1 1, Tanzania]
2006 Paragloborotalia nana Bolli. - Pearson et al. : p.86 pl. 5.8; fig. 1-16 (Pl. 5.8, Figs. 1-3: new SEMs of holotype of Globorotalia opima nana Bolli)
Specimen:
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM P5661
References:

Bolli,H.M. (1957):
Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I..
In: Studies in Foraminifery, Bulletin of the U.S. National Museum Vol. 215 Eds: Loeblich, A.R.Tappan, H.Beckmann, J.P.Bolli, H.M.Gallitelli, E.M.Troelsen, J.C. p. 97-123

Blow,W.H. (1969):
Late middle Eocene to Recent planktonic foraminiferal biostratigraphy.
In: Proceedings of the First International Conference on Planktonic Microfossils, Geneva 1967 Vol. 1 Eds: Bronnimann, P.Renz, H.H. p. 199-422

Krasheninnikov,V.A. and Pflaumann,U. (1977):
Zonal stratigraphy and planktonic foraminifers of Paleogene deposits of the Atlantic Ocean to the west of Africa (Deep Sea Drilling Project, Leg 41).
In: Initial Reports of the Deep Sea Drilling Project Vol. 41 Eds: Lancelot, Y..Seibold, E..and others p. 581-612

Toumarkine,M. (1978):
Planktonic Foraminiferal Biostratigraphy of the Paleogene of Sites 360 to 364 and the Neogene of Sites 362A, 363, and 364 Leg 40.
In: Initial Results of the Deep Sea Drilling Project Vol. 40

Kennett,J. and Srinivasan,M.S. (1983):
Neogene Planktonic Foraminifera - A Phylogenetic Atlas.

Bolli,H.M. and Saunders,J.B. (1985):
Oligocene to Holocene low latitude planktic foraminifers.
In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262

Chaisson,W.P. and Leckie,R.M. (1993):
High-Resolution Planktonic Foraminifer Biostratigraphy of Site 806, Ontong Java Plateau (Western Equatorial Pacific).
In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 130 Eds: Berger, W.H.Kroenke, L.W..Mayer, L.A..et al. p. 137-178

Poag,C.W.. and Commeau,J.A.. (1995):
Paleocene to middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: biostratigraphy, allostratigraphy, and sequence stratigraphy . Journal of Foraminiferal Research Vol. 25 p. 134-155

Pearson,P.N.; Nicholas,C.J..; Singano,J.M..; Bown,P.R..; Coxali,H.K..; van Dongen,B.E..; Huber,B.T.; Karega,A..; Lees,J.A..; Misaky,E..; Pancost,R.D..; Pearson,M.. and Roberts,A.P.. (2004):
Paleogene and Cretaceous sediment cores from the Kilwa and Lindi areas of coastal Tanzania: Tanzania Drilling Project Sites 1-5 . Journal of African Earth Sciences Vol. 39 p. 25-62

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

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