Globanomalina luxorensis


Classification: pf_cenozoic -> smooth non-spinose -> Hedbergellidae -> Globanomalina -> Globanomalina luxorensis
Sister taxa: G. australiformis, G. luxorensis, G. ovalis, G. imitata, G. planocompressa, G. planoconica, G. chapmani, G. pseudomenardii, G. ehrenbergi, G. compressa, G. archeocompressa, G. sp.,

Taxonomy

Citation: Globanomalina luxorensis (Nakkady 1950)
Rank: Species
Basionym: Anomalina luxorensis
Synonyms:
Taxonomic discussion: Globanomalina luxorensis has been a poorly known species since it was first described. This may, in part, be due to its limited occurrence and abundance in the stratigraphic record and, perhaps, to its having been overlooked or included in Globanomalina chapmani, Globanomalina ovalis Haque, 1956, or Pseudohastigerina wilcoxensis. Banner (1989) concluded that G. luxorensis could be separated from G. ovalis, although he earlier (Banner, 1982) had considered G. luxorensis as the senior synonym of G. ovalis He regarded G. luxorensis as the immediate ancestor of P. wilcoxensis. Recently, Speijer and Samir (1997) noted the association of G. luxorensis with the negative ∂13C excursion in the middle part of Zone P5 (of Berggren and others, 1995), which they suggested as the point for marking the boundary between the Paleocene and the Eocene in a Global Stratotype Section and Point (GSSP). However, they concluded, in contrast to Banner (1989), that G. ovalis was a junior synonym of G. luxorensis and found that in Egypt G. luxorensis was extremely rare below the ∂13C excursion. We would agree with Banner that the two species can be separated, but part of the confusion appears to be due to poor
preservation (see Banner, 1989) and to lack of sufficient specimens below the ∂13C excursion. Globanomalina ovalis is common in Zone P4 in southern India (Olsson and others, 1999), which suggests that the species was common in the Indian Ocean region, and records of the species in New Zealand indicate its widespread distribution in the late Paleocene.
Globanomalina ovalis usually has 5 chambers in the ultimate whorl in contrast to G. luxorensis which usually has 6-7 chambers in the ultimate whorl. Occasionally, 6-chambered forms and 5-chambered forms are found in assemblages of each species, respectively (see Speijer and Samir, pl 2, figs. 2a-c as an example). The chambers in G. ovalis in edge view are oval in shape, and wider than high. Because of this, the chambers tend to extend over the spiral side presenting a planispiral appearance and, as Banner (1989) noted, the spiral “side becomes incompletely evolute and slightly concave in shape” (p. 177). The aperture, however, only extends extraumbilically to the medium point of the axial periphery, in contrast to G. luxorensis where the aperture extends slightly over the axial periphery but not to the trace of the spiral suture. In edge view the chambers in G. luxorensis are more globular, equidimensional, or even slightly compressed. Given these morphological criteria the morphotype recorded as ex interc G. (T.) chapmani Parr and Pseudohastigerina wilcoxensis (Cushman and Ponton) by Blow (1979, pl. 111: fig. 5) is more appropriately placed in G. luxorensis rather than in G. ovalis (as recorded by Olsson and others, 1999). [Olsson & Hemleben 2006]

Catalog entries: Anomalina luxorensis;

Type images:

Short diagnosis: Test very low trochospiral. Chambers globular. Axial periphery rounded. Aperture arched, extending over axial periphery to spiral side, but not to the trace of the spiral suture.

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.

Description


Diagnostic characters: Globanomalina luxorensis is characterized by its very low trochospiral test, globular chambers, rounded axial periphery, and an arched aperture that extends over the axial periphery to the spiral side, but not to the trace of the spiral suture. The species is regarded as representing the transitional morphology from a trochospiral to a planispiral test, but is not planispiral according to the criterion of Blow (1979, p. 1060; discussed above). [Olsson & Hemleben 2006]

Wall type: Smooth, normal perforate. [Olsson & Hemleben 2006]

Test morphology: Test very low trochospiral, compressed, tightly coiled, oval in outline, slightly lobulate; chambers inflated, globular; in umbilical view normally 6 to 7 chambers in ultimate whorl, increasing rapidly in size, sutures moderately depressed, straight to slightly curved, umbilicus small, circular in shape; in spiral view 6 to 7, occasionally 5 or up to 8, chambers in ultimate whorl, increasing rapidly in size, sutures moderately depressed, straight to slightly curved, inner whorl of chambers depressed, evolute to partly involute; in edge view primary aperture an oval, umbilical extraumbilical high arch bordered by a narrow lip which extends slightly onto the spiral side but not to the spiral suture; test compressed with a rounded periphery; peripheral margin perforate. [Olsson & Hemleben 2006]

Size: Maximum diameter of holotype 0.25 mm, thickness 0.15 mm. [Olsson & Hemleben 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Compressedaperture:-
umb chamber shape:Inflatedcoiling axis:Very lowperiphery:N/Aaperture border:Thin lip
sp chbr shape:Inflatedumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:N/A
umbilical or test sutures:Strongly depressedumb depth:Shallowwall texture:Smoothshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:Strongly depresseddiameter mm:0.25width mm:breadth mm:0.15
final-whorl chambers:6.0-7.0

Biogeography and Palaeobiology


Geographic distribution: Global in low to mid latitudes. [Olsson & Hemleben 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson & Hemleben (2006)

Isotope paleobiology: Our data show relatively negative oxygen values that suggest a shallow habitat above the thermocline (R. K. Olsson, unpublished data). [Olsson & Hemleben 2006]
Aze et al. 2011 ecogroup 2 - Open ocean mixed-layer tropical/subtropical, without symbionts. Based on δ13C lighter than species with symbionts; also with relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): Olsson & Hemleben (2006)

Phylogenetic relations: Globanomalina luxorensis evolved from G. ovalis by an increase of number of chambers in the final whorl, development of more globular equidimensional chambers, and by the migration of the aperture slightly over the axial periphery onto the spiral side. In turn, G. luxorensis gave rise to Pseudohastigerina wilcoxensis through the development of an equatorial aperture and a planispiral test. The species is the end-member of the Globanomalina imitata -G. ovalis-G. luxorensis lineage which led to the genus Pseudohastigerina. [Olsson & Hemleben 2006]

Most likely ancestor: Globanomalina ovalis - at confidence level 4 (out of 5). Data source: Olsson & Hemleben 2006, fig14.1.

Biostratigraphic distribution

Geological Range:
Notes: Zone P5 to top of Zone E3. [Olsson & Hemleben 2006]
Last occurrence (top): at top of E2 zone (100% up, 55.2Ma, in Ypresian stage). Data source: Olsson & Hemleben 2006, fig14.1
First occurrence (base): in upper part of P5 zone (70% up, 56.3Ma, in Thanetian stage). Data source: Olsson & Hemleben 2006, fig14.1

Plot of occurrence data:

Primary source for this page: Olsson & Hemleben 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 14, p. 415

References:

Banner, F.T., (1982). A classification and introduction to the Globigerinacea. Aspects of Micropaleontology (papers presented to Professor Tom Barnard). Allen and Unwin, London, 142-239 pp.

Banner, F.T., (1989). The nature of Globanomalina Haque, 1956. Journal of Foraminiferal Research, 19: 171-179.

Berggren, W.; Olsson, R. & Reyment, R., (1967). Origin and Development of the Foraminiferal Genus Pseudohastigerina Banner and Blow, 1959. Micropaleontology, 13: 265-288.

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.

Berggren, W.A.; Kent, D.V.; Swisher, I., C.C. & Aubry, M.-P., (1995). A revised Cenozoic geochronology and chronostratigraphy. In: Berggren, W.A. et al. (Editors), Geochronology, Time Scales and Global Stratigraphic Correlations. SEPM (Society for Sedimentary Geology) Special Publication No. 54.

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, 1413 pp.

Cushman, J.A. & Ponton, G.M., (1932). An Eocene foraminiferal fauna of Wilcox age from Alabama. Contributions from the Cushman Laboratory for Foraminiferal Research, 8: 51-72.

Haque, A.F.M.M., (1956). The smaller foraminifera of the Ranikot and the Laki of the Nammal gorge, Salt Range. Memoir of the Pakistan Geological Survey, 1: 1-300.

Nakkady, S.E., (1950). A new foraminiferal fauna from the Esna shales and Upper Cretaceous chalk of Egypt. Journal of Paleontology, 24(6): 675-692.

Nakkady, S.E., (1951). Zoning the Mesozioic-Cenozoic trasition of Egypt by the Globorotaliidae. Bulletin of the Faculty of Science: 45-58.

Nakkady, E., (1959). Biostratigraphy of the Um Elghanayem section, Egypt. Micropaleontology, 5: 453-472.

Olsson, R.K. & Hemleben, C., (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Globanomalina, Planoglobanomalina n. gen and Pseudohastigerina. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Cushman Foundation Special Publication. Allen Press, Lawrence, Kansas, pp. 413-432.

Olsson & Reyment 1967 [sorry, not in our bibliography yet]

Olsson, R.K.; Hemleben, C.; Berggren, W.A. & Huber, B.T., (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Contributions to Paleobiology. Smithsonian Institution Press, Washington, DC, 1-252 pp.

Parr, W.J., (1938). Upper Eocene Foraminifera from Deep Borings in King's Park, Perth, Western Australia. Journal of the Royal Society of Western Australia, 24: 69-101.

Speijer, R.P. & Samir, A.M., (1997). Globanomalina luxorensis, a Tethyan biostratigraphic marker of latest Paleocene global events. Micropaleontology, 43: 51-62.

Stainforth, R.M.; Lamb, J.L.; Luterbacher, H.; Beard, J.H. & Jeffords, R.M., (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. The University of Kansas Paleontological Contributions, 62: 1-425.

Stott, L.D. & Kennett, J.P., (1990). The Paleoceanographic and Paleoclimatic signature of the Cretaceous/Paleogene boundary in the Antarctic: Stable isotopic results from ODP Leg 113. Proceedings of the Ocean Drilling Program, Scientific Results, 113: 829-848.


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Globanomalina luxorensis compiled by the pforams@mikrotax project team viewed: 17-11-2017

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