Clavigerinella jarvisi Cushman 1930 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 Clavigerinella jarvisi Cushman 1930 |
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| Diagnosis / Definition: |
Pearson et al. (2006):
DESCRIPTION.
Type ofwall: Usually smooth, normal perforate,
sometimes weakly cancellate; possibly spinose in life.
Test morphology: Planispiral or pseudoplanispiral,
evolute, biumbilicate or showing a slightly
raised spiral side and very shallow umbilicus; 4-4112
chambers in the final whorl; increasing rapidly in size
as added, early chambers rounded, final 2-3 chambers
rapidly elongating into slender, cylindrical fingers
(digitate); distal chamber ends smooth and rounded or
slightly tapered; equatorial high arched aperture,
symmetrical or slightly asymmetrical, bordered by a
broad imperforate lip; sutures shallow, straight,
becoming curved in later stages, short compared to the
overall chamber length.
Size: Up to 0.545 mm (Cushman, 1930).
Detached chambers can be 0.40 mm, suggesting some
specimens are as large as 1 mm. |
| Discussion / Comments: |
Pearson et al. (2006):
DISTINGUISHING FEATURES.-
The adult
chambers of this species are significantly longer and
more slender than in C. eocanica and C. caucasica and
lack the terminal swellings of C. akersi. Clavigerinella
jarvisi differs from "Clavatorella " nazcaensis Quilty in
the larger size and more regular pattern of size increase
of the chambers in the final whorl. It is comparable to
Cretaceous Clavihedbergella watersi but has less
bulbous chambers and a non-pustulose wall.
DISCUSSION.-
Blow (1979) did not subdivide
Clavigerinella based on chamber length, believing this
character to be a function of growth stage and
environmental factors, helgce he placed C. jarvisi in
synonymy with C. eocanica. Our observations of
Clavigerinella from a number of sites (ODP Sites 865,
960, 121 8, Kane 9-C) indicate that a C. jarvisi
morphotype with long finger-like chambers can be
distinguished from the moderately clavate form C.
eocanica. Complete specimens of this species are
extremely rare and it is usually recognised by the
detached digitate adult chambers, which are easily
recognized by the porous chamber surface and remnants
of the apertural arch (PI. 8.2, Figs. 8, 9). We find no
evidence for the presence of "roughened projections"
representing spine bases as indicated by Cushman's
(1930) original description and find no link to the
modem digitate form Hastigerinella digitata.
PHYLOGENETIC RELATIONSHIPS.-
This species
probably evolved from C. eocanica in uppermost Zone
E7 by extension and tapering of the final chambers.
STRATIGRAPHIC RANGE.-
Zone E7-E 10. Last
occurrence poorly constrained.
GEOGRAPHIC DISTRIBUTION.-
Worldwide in low
and mid-latitudes. Rare in oligotrophic open ocean
sections, occasionally common in upwelling
assemblages. Based on the occurrence of common C.
jarvisi (recorded as C. eocanica) together with
radiolarian-rich sediments in Peru and Ecuador,
Stainforth (1948) suggested this species thrived in the
cold waters of northward flowing ex-polar currents. His claim that this species is a strictly cold-water specialist
cannot be substantiated, however, since it has never been
found in polar regions. More likely, the occurrence of
C. jarvisi was linked to western continental margin
upwelling.
STABLE ISOTOPE PALEOB1OLOGY.-
No data
available. |
| Systematics: |
24
Genus Clavigerinella
Species Clavigerinella jarvisi
35
Ordo Foraminiferida
Superfamilia Globigerinaceae
Familia Hantkeninidae
Genus Clavigerinella
Genus Hantkenina
Species Clavigerinella jarvisi
Species Hantkenina alabamensis
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| Synonym list: |
Bolli (1957):
Pearson et al. (2006):
1948 Hastigerinella eocanica Nuttall. - Stainforth : p. 116-117 pl. 26; fig. 18, 19 (detached chambers) [upper Eocene,
Ecuador]
1955 Hastigerinella eocanica Nuttall. - Weiss : p.309 pl. 2; fig. 11-13 [middle
Eocene Talara, Chira and Mirador Fms, Northern Peru];
[Not Nuttall, 1930]
non 1971 Clavigerinella jarvisi Cushman. - Postuma : p.132 pl. on p. 133 (4 specimens, right hand column) [Eocene
Globorotalia bullbrooki Zone to Globigerapsis kugleri
Zone, Navet Fm. Trinidad]; (= Clavigerinella eocanica)
2006 Clavigerinella jarvisi Cushman. - Pearson et al. : p.220 pl. 8.2; fig. 14-18 (PI. 8.2, Fig. 14: new SEMs of the holotype of
Hastigerinella jarvisi Cushman);
(Pl. 8.2, Figs. 17-18: new SEMs of the holotype of
Hastigerinella eocanica var. aragonensis Nuttall)
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| Was used in synonym list of: |
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| Specimen: |
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 12565
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 12566-12567
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 370415
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| References: |
Cushman,J.A. (1930):
Fossil species of Hastigerinella . Contributions from the Cushman Foundation for Foraminiferal Research Vol. 6 p. 17-19
Nuttall,W.L.F. (1930):
Eocene foraminifera from Mexico . Journal of Paleontology Vol. 4 p. 271-293
Stainforth,R.M. (1948):
Applied micropaleontology in Coastal Ecuador . Journ. Paleontol. Vol. 22(2) p. 113-151
Weiss,L. (1955):
Planktonic index Foraminifera of northwestern Peru . Micropaleontology Vol. 1(4) p. 301-308
Bolli,H.M. (1957):
Planktonic Foraminifera from the Eocene Navet and San Fernando formations of Trinidad, B.W.I. . Bull. U.S. natl. Mus. Vol. 215 p. 155-172
Postuma,J.A. (1971):
Manual of Planktonic Foraminifera. p. 422 pp
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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