Globorotaloides eovariabilis Huber & Pearson 2006 from: Pearson, P.N.Olsson, R.K.Hemleben, C.Huber, B.T.Berggren, W.A. (2006): Atlas of Eocene Planktonic Foraminifera. p. 1-513 . |
Notice: This catalogue page may contain unedited data.
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Species Globorotaloides eovariabilis Huber & Pearson 2006 |
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Diagnosis / Definition: |
Pearson et al. (2006):
DESCRIPTION.
Type of wall: Normal perforate, coarsely
cancellate, succulifer-type wall texture, often with
corroded interpore ridges reeking in a remnant wall
texture consisting of distinct 'rosettes' around the pores.
Test morphology: Test outline lobate, subcircular
in axial view, axial periphery rounded to very slightly
compressed, biconvex, oval to egg-shaped in edge view;
3-31/2 whorls of slightly inflated chambers arranged in a
flattened to slightly elevated trochospire; 14- 15
chambers in adult tests, 41/74 in the final whorl increasing
moderately in size; umbilicus shallow to moderately
deep and narrow; umbilical suture:-moderately
depressed, radial; spiral initially indistinct, later weakly
depressed, radial; aperture a low umbilicalextraumbilical
arch extending one-third towards
peripheral margin, surrounded by a broad lip that extends
into the umbilical area.
Size: Holotype (USNM 523429) maximum
diameter 0.18 mm, breadth 0.10 mm; paratype a (USNM
523430) maximum diameter 0.13 mm, breadth 0.80 mm;
paratype b (USNM 523430) maximum diameter 0.15
m. breadth 0.93 mm. |
Discussion / Comments: |
Pearson et al. (2006):
ETYMOLOGY.- Named as "dawn" vaiabilis because
of its superficial resemblance to the much younger
species Globorotaloides vuriabilis Bolli.
DISTINGUISHING FEATURES.- Differs from
Globorotaloides quadrocameratus n. sp. by having 41/2
to 6, rather than 4-41/2, final whorl chambers that are
less inflated and increase more gradually in size; differs
from Globorotaloides variabilis by its smaller size and
less flat inner whorl.
DISCUSSION.-This form has been widely recognized
at high latitude sites using various species names and
open nomenclature. It is included in Globorotaloides
because of its coarsely cancellate wall texture and low,
sometimes flattened spiral coil. Specimens frequently
exhibit corroded interpore ridges with a remnant surface
texture consisting of a distinct rosette pattern (PI. 5.4,
Figs. 4, 13-15). A high latitude form from the lower
Eocene of Site 690 (Maud Rise) that may be related to
this species was designated by Stott and Kennett (1990,
pl. 5, figs. 3-4) as "Tenuitella" reissi (Loeblich and
Tappan). This morphotype has a similar coarsely
reticulate wall texture but it is higher spired and the
equatorial margin is more compressed.
PHYLOGENETIC RELATIONSHIPS.- Descended
from Globorotaloides quadrocamerutus n. sp. during the
early Eocene. Intermediate morphologies can be found
(e.g.,Pl. 5.5, Figs. 13-15).
GEOGRAPHIC DISTRIBUTION.-Found at deep-sea
sites in southern and northern high latitudes but not at
middle or low latitudes.
STABLE ISOTOPIC PALEOBIOLOGY.- No data available.
TYPE LOCALITY.- The holotype and paratype are
from the middle Eocene of ODP Hole 647A (Sample
647A-50R-5,101 cm) in the Labrador Basin. which was
assigned to calcareous nannofossil Zone NP 16 by Firth
(1989). |
Systematics: |
35 Ordo Foraminiferida
Superfamilia Globigerinaceae
Familia Globigerinidae
Genus Turborotalita
Species Globorotaloides eovariabilis
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Synonym list: |
Pearson et al. (2006):
1975 Clavigerinella? columbiana Petters. - McKeel & Lipps : p.258 pl. 3, fig. Xa-c (partim; not pl. 4: fig. 6a, b =
Parasubbotina eoclava Coxall, Huber, and Pearson) [lower middle Eocene, Elkton Siltstone, Coast Ranges,
Oregon]. [Not Petters, 1954.]
? 1979 Globorotalia (Turborotalia) pseudoimitata Blow. - Blow : p. 1104-1105 pl. 101, fig. 1-3 [upper Paleocene Zone
P5, DSDP Site 47, Shatsky Rise, northwest Pacific Ocean];
pl. 106, fig. 2-10;
pl. 108, fig. 1-3 [lower Eocene Zone
P6, Hole 20C, South Atlantic Ocean]
p 1983 Globorotalia munda Jenkins. - Krasheninnikov & Basov : p.841 pl. 10; fig. 101 [lower Eocene, DSDP
Site 511, Falkland Plateau, South Atlantic].[Not Jenkins,
1966.]
1990 Globorotaloides aff. testarugosa Jenkins. - Stott & Kennett : p.560 pl. 7; fig. 11 [middle Eocene Zone
AE415, ODP Hole 689B, Maud Rise, southern South
Atlantic]
1991 Globorotaloides aff. testarugosa Jenkins. - Huber : p.440 pl. 7; fig. 19, 20 [lower
Oligocene, Zone AE9, ODP Hole 738B, Kerguelen
Plateau, southern Indian Ocean]. [Not Jenkins, 1971 .]
1991 "Planorotalites" reissi Loeblich & Tappan. - Huber : p.440 pl. 4; fig. 18-20 [lower Eocene Zone AE4/5,
ODP Hole 738C, Kerguelen Plateau, southern Indian
Ocean]. [Not Loeblich and Tappan, 1957.]
1991 Globorotaloides aff. suteri Bolli. - Nocchi et al. : p.268 pl. 4; fig. 4, 5 [lower middle Eocene Zone E8-
E9, ODP Site 699, southern South Atlantic]. [Not Bolli,
1957b.]
1992 Globorotaloides suteri Bolli. - Berggren : p.564 pl. 4; fig. 4 [upper Eocene G. suteri Zone ODP Hole 748B,
Kerguelen Plateau, southern Indian Ocean]. [Not Bolli,
1957b.]
1992 Globorotaloides sp. 1 Berggren. - Berggren : p.568 pl. 4; fig. 11 [upper Eocene G. suteri Zone, ODP Hole 748B, Kerguelen
Plateau, southern Indian Ocean]
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Specimen: |
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 523429
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 523430a
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 523430b
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References: |
McKeel,D.R.. and Lipps,J.H. (1975): Eocene and Oligocene planktonic foraminifera from the central and southern Oregon coast range . Journal of Foraminiferal Research Vol. 5 p. 1-5
Blow,W.H. (1979): The Cainozoic Globigerinida. 3 Vols p. 1413 pp
Krasheninnikov,V.A. and Basov,I.A. (1983): Cenozoic planktonic foraminifers of the Falkland Plateau and Argentine Basin, Deep Sea Drilling Projejt Leg 71. In: Initial Reports of the Deep Sea Drilling Project Vol. 71 Eds: Ludwig, W.J.Krasheninninov, V.A. p. 821-845
Stott,L.D. and Kennett,J.P. (1990): Antarctic Paleogene planktonic foraminifer biostratigraphy:ODP Leg 113, Sites 689 and 690. In: Proceedings of the Ocean Drilling Program Vol. 113
Nocchi,M.; Amici,E. and Premoli Silva,I. (1991): Planktonic Foraminiferal Biostratigraphy and Paleoenvironmental Interpretation of Paleocene Faunas from the Subantartic Transect, Leg 114. In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 114 Eds: Ciesielski, P.F.Kristoffersen, Y.Al, E. p. 233-279
Huber,B.T. (1991): Paleogene and early Neogene planktonic foraminifer biostratigraphy of Sites 738 and 744, Kerguelen Plateau (southern Indian Ocean). In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 119 Eds: Leckie, R.M.Sigurdsson, H.Acton, G.D.Draper, G. p. 427-449
Berggren,W.A. (1992): Paleogene Planktonic Foraminifera Magnetobiostratigraphy of the Southern Kerguelen Plateau (Sites 747-749). In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 120
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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