Pseudohastigerina sharkriverensis Berggren & Olsson 1967 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 Pseudohastigerina sharkriverensis Berggren & Olsson 1967 |
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| Diagnosis / Definition: |
Pearson et al. (2006):
DESCRIPTION.
Type of wall: Smooth, normal perforate.
Test morphology: Test planispiral, compressed,
tightly coiled, involute, oval to quadrate in outline,
slightly lobulate, chambers, inflated, globular; in
umbilical view 6 chambers in ultimate whorl with the
final 3 composing about two-thirds of the test size, first
4 chambers increasing rapidly in size and the final 2
chambers more gradually in size, ultimate chamber
sometimes slightly reduced in size, sutures moderately
depressed, straight to slightly curved, umbilicus small,
circular in shape; in edge view chambers much inflated,
oval to nearly circular in outline, primary aperture an
oval low arch, bordered by a narrow lip, bipartite
apertures a common feature in adult specimens, test
compressed with a rounded periphery; peripheral margin
perforate.
Size: Maximum diameter of holotype 0.35 mm,
thickness 0.20 mm. |
| Discussion / Comments: |
Pearson et al. (2006):
DISTINGUISHTNG FEATURES.-
Pseudohastigerina
sharkriverensis is characterized by its large oval to
quadrate test, much inflated globular chambers, the
slower chamber growth in the final 3 chambers and the
common development of bipartite apertures in the final
chamber. In edge view the chambers are much inflated
in contrast to the more compressed chambers in P.
wilcoxensis.
DISCUSSION.-
This species has not been widely
recorded in the published literature, which may in part
be due to its mid-latitude biogeographic restriction. The
only discussion of the species was by Blow (1 979) who
stated (p. 11 92) "In the writer's view, the production of
the sharkriverensis-morphotype is a strict allometric and
orthogenetic development of the wilcoxensis-morphotypes
to the limits imposed by the geometry of
planispirally coiled forms with inflated chambers". He
apparently based his opinion on his belief that the
development of a bipartite apertural system was due to
a tightening of the chamber coil and greater inflation of
chambers that first occurred in P wilcoxensis. However,
bipartite apertures are also seen in Pseudohastigerina
micra (Cole) which has much compressed chambers, so
that bipartite apertures appear to be a feature of the
Pseudohastigerina group of species. The evolution of
P. sharkriverensis from P. wilcoxensis can not be
regarded as strictly an allometric development because
there is a change in chamber shape.
Blow suggested that Biglobigerinella kerisensis
Suleymanov (1966) might be a senior synonym of P
sharkriverensis. Biglobigerinella kerisensis was
described from the upper Eocene of Kizil Kum, central
Asia of the former Soviet Union. Scanning electron
micrographs of the holotype of this species (Pl. 14.4,
Figs. 13-15) show a deformed specimen with an
asymmetrical ultimate chamber which extends over and
obscures the umbilical area of one side. Although the
specimen appears to be planispiral, it is difficult to make
a meaningful morphological comparison with P.
sharkriverensis without additional specimens. Since P
sharkriverensis is not known to range above the middle
Eocene and B. kerisensis is poorly known and not well
documented, it is advisable to use the former name.
Globigerinella pseudovoluta Bandy (1949) was also
mentioned by Blow as a possible senior synonym of P
sharkriverensis but this species is more properly placed
in P. wilcoxensis because the chambers are more compressed in edge view, the aperture is highly arched,
and there is a regular increase in chamber size, all typical
features of P. wilcoxensis.
PHYLOGENETIC RELATIONSHIPS.-
Pseudohastigerina sharkriverensis evolved from P. wilcoxensis
by an increase in size of the test, a slowly of chamber
size increase in the last few chambers of the ultimate
whorl, and by a change in chamber shape from
compressed to globular inflated chambers. The aperture
is reduced to a low arch in the transition.
STRATIGRAPHIC RANGE.-
Middle Eocene, Zone E7? to Zone E1 3?
GEOGRAPHIC DISTRIBUTION.-
Apparently
restricted distribution in mid latitudes.
STABLE ISOTOPE PALEOBIOL0GY.-
No data
available. |
| Systematics: |
35
Ordo Foraminiferida
Superfamilia Globigerinaceae
Familia Hedbergellidae
Genus Pseudohastigerina
Species Pseudohastigerina sharkriverensis
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| Synonym list: |
Pearson et al. (2006):
p 1953 Globigerinella voluta White. - Subbotina : p.87 pl. 13; fig. 13a-b [middle Eocene Acarinina zone, Kuban River, Northern Caucasus];
fig. 14a-b [lower-middle Eocene Zone of conical Globorotalia, Khieu River, northern Caucasus] (not fig. 15a-b = Pseudohastigerina wileoxensis); [Not White, 1928]
1967 Pseudohastigerina sharkriverensis Berggren & Olsson. - Berggren et al. : p.280 pl. 1, fig. 7-8 (holotype); 9- 11 (paratype); text-fig. 7, 1a-9c (paratypes);
text-fig. 8, 10a- 14c (paratypes) [middle Eocene, Shark
River Fm., New Jersey]
1979 Pseudohastigerina sharkriverensis Berggren & Olsson. - Blow : p.1191 pl. 252, fig. 5-7 [lower Eocene Zone P9, Tuilerie de Gan, southwest France];
fig. 8- 10 [lower Eocene Zone P 12- 14, Steenberg, stratotype Ledian, Bambrugge, Belgium]
2006 Pseudohastigerina sharkriverensis Berggren & Olsson. - Pearson et al. : p.429 pl. 14.4; fig. 9-16 (Pl. 14.4, Figs. 9, 10: new SEMs of holotype of
Pseudohastigerina sharkriverensis Berggren and
Olsson)
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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 509801
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 509802
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| References: |
Subbotina,N.N. (1953):
Iskopaemye foraminifery SSSR (Globigerinidy, Khantkenininidy i Globorotaliidy) . Trudy Vsesoyznogo Nauchno-Issledovatel'skogo Geologo-razvedochnogo Instituta (VNIGRI) Vol. 76 p. 296
Suleymanov,I.V.. (1966):
New Upper Eocene species of the genus Biglobigerinella . Moskv. Univ., Paleontologicheskiy Zhumal [in Russian] Vol. 1 p. 148-150
Berggren,W.A.; Olsson,R.K. and Reyment,R.A. (1967):
Origin and Development of the Foraminiferal Genus Pseudohastigerina Banner and Blow, 1959 . Micropaleontology Vol. 13 p. 265-288
McKeel,D.R.. and Lipps,J.H. (1972):
Calcareous plankton from the Tertiary of Oregon . Palaeogeography, Palaeoclimatology, Palaeoecology Vol. 12 p. 75-93
Blow,W.H. (1979):
The Cainozoic Globigerinida. 3 Vols p. 1413 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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