pforams@mikrotax - Pseudohastigerina sharkriverensis

pforams@mikrotax - Pseudohastigerina sharkriverensis pforams@mikrotax - Pseudohastigerina sharkriverensis

Pseudohastigerina sharkriverensis

Classification: pf_cenozoic -> Globanomalinidae -> Pseudohastigerina -> Pseudohastigerina sharkriverensis
Sister taxa: P. naguewichiensis, P. micra, P. sharkriverensis, P. wilcoxensis, P. sp.

Eocene_Atlas_pl14-4_fig11-16.jpg

Taxonomy

Citation: Pseudohastigerina sharkriverensis Berggren&Olsson 1967

taxonomic rank: Species

Basionym: Pseudohastigerina sharkriverensis

Synonyms:

?Biglobigerinella kerisensis Suleymanov, 1966:148, pl.1: fig. 1a, b, [upper Eocene of Kizil Kum, central Asia]
Globigerinella voluta (White). —Subbotina, 1953:87 (partim; not fig. 15a-b = Pseudohastigerina wilcoxensis), 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 White, 1928.]
Pseudohastigerina sharkriverensis Berggren and Olsson, 1967 in Berggren and others, 1967:280, pl. 1: figs. 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].—McKeel and Lipps, 1972:83, pl.1: fig, 7a, b [middle Eocene, Tyee Fm., Coast Range, Oregon]._Blow, 1979:1191, pl. 252: figs. 5-7 [lower Eocene Zone P9, Tuilerie de Gan, southwest France]; figs. 8-10 [lower Eocene Zone P12-14, Steenberg, stratotype Ledian, Bambrugge, Belgium].

Taxonomic 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 (1979) who stated (p. 1192) “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. [Olsson & Hemleben 2006]

Catalog entries: Pseudohastigerina sharkriverensis

Type images:

holotype: P. sharkriverensis

Distinguishing features:
Parent taxon (Pseudohastigerina): Planispiral.
Aperture equatorial, sometimes bipartite, may be asymmetrical.
Wall smooth, normally perforate.
This taxon: Test large, oval to quadrate; chambers much inflated, globular. Low chamber growth in final 3 chambers bipartite apertures common.

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
They are being edited as the site is developed and comments on them are especially welcome.

Description

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. [Olsson & Hemleben 2006]

Wall type:

Smooth, normal perforate. [Olsson & Hemleben 2006]

Size:

Maximum diameter of holotype 0.35 mm, thickness 0.20 mm. [Olsson & Hemleben 2006]

Character matrix
test outline: Quadrate chamber arrangement: Planispiral edge view: Equally biconvex aperture: Biapertural
sp chamber shape: Inflated coiling axis: N/A periphery: N/A aperture border: Thin lip
umb chbr shape: Inflated umbilicus: Narrow periph margin shape: Moderately rounded accessory apertures: Intralaminal
spiral sutures: Moderately depressed umb depth: Shallow wall texture: Smooth shell porosity: Finely Perforate: 1-2.5µm
umbilical or test sutures: Moderately depressed final-whorl chambers: 5.5-6.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Apparently restricted distribution in mid latitudes. [Olsson & Hemleben 2006]
Aze et al. 2011 summary: Middle latitudes only; based on Olsson & Hemleben (2006)

Isotope paleobiology

No data available. [Olsson et al. 1999]
Aze et al. 2011 ecogroup 2 - Open ocean mixed-layer tropical/subtropical, without symbionts; based on comparison with other species of the genus.

Phylogenetic relations

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. [Olsson & Hemleben 2006]

Most likely ancestor: Pseudohastigerina wilcoxensis - at confidence level 4 (out of 5). Data source: Olsson & Hemleben (2006) fig 14.1.

Biostratigraphic distribution

Geological Range:
Notes: Middle Eocene, Zone E7? to Zone E13? [Olsson & Hemleben 2006 ]
Last occurrence (top): within E13 zone (37.99-39.97Ma, top in Bartonian stage). Data source: Olsson & Hemleben (2006) fig 14.1
First occurrence (base): within E7a subzone (48.31-50.20Ma, base in Ypresian stage). Data source: Olsson & Hemleben (2006) fig 14.1

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
(NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Pseudohastigerina

Primary source for this page: Olsson & Hemleben 2006 - Eocene Atlas, chap. 14, p. 426

References:

Bandy, O. L. (1949). Eocene and Oligocene foraminifera from Little Stave Creek, Clarke County, Alabama. Bulletins of American Paleontology. 32(131): 1-210. gs

Berggren, W. A., Olsson, R. K. & Reyment, R. A. (1967). Origin and development of the foraminiferal genus Pseudohastigerina Banner and Blow, 1959. Micropaleontology. 13(3): 265-288. gs

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs

McKeel, D. R. & Lipps, J. H. (1972). Calcareous plankton from the Tertiary of Oregon. Palaeogeography Palaeoclimatology Palaeoecology. 12(1-2): 75-93. gs

Olsson, R. K. & Hemleben, C. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Globanomalina, Planoglobanomalina n. gen and Pseudohastigerina. In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 14): 413-432. gs O

Suleymanov, I. S. (1966). New upper Eocene species of the genus Biglobigerinella. Paleontologicheskiy Zhurnal. (1): 148-149. gs

White, M. P. (1928). Some Index Foraminifera of the Tampico Embayment Area of Mexico. Journal of Paleontology. 2(3): 177-215. gs

Pseudohastigerina sharkriverensis compiled by the pforams@mikrotax project team viewed: 6-10-2024

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test outline:	Quadrate	chamber arrangement:	Planispiral	edge view:	Equally biconvex	aperture:	Biapertural
sp chamber shape:	Inflated	coiling axis:	N/A	periphery:	N/A	aperture border:	Thin lip
umb chbr shape:	Inflated	umbilicus:	Narrow	periph margin shape:	Moderately rounded	accessory apertures:	Intralaminal
spiral sutures:	Moderately depressed	umb depth:	Shallow	wall texture:	Smooth	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Moderately depressed	final-whorl chambers:	5.5-6.5	N.B. These characters are used for advanced search. N/A - not applicable