Eoglobigerina edita


Classification: pf_cenozoic -> spinose -> Globigerinidae -> Eoglobigerina -> Eoglobigerina edita
Sister taxa: E. edita, E. eobulloides, E. spiralis, E. sp.,

Taxonomy

Citation: Eoglobigerina edita (Subbotina 1953)
Rank: Species
Basionym: Globigerina edita
Synonyms:
Taxonomic discussion: A considerable variation in the height of the initial coil and the position of the aperture from an umbilical toward an extraumbilical position occurs in this species. Blow (1979) discussed the high degree of variability among early eoglobigerinids and the apparent fact that few morphotypes exhibit a consistent expression of morphologic characters. Thus, he cautioned that strict morphologic limits cannot be as rigidly applied to early eoglobigerinids as to the later, more stable morphospecies of globigerinacean genera. Blow also distinguished as a subspecies of edita the morphospecies
praeedita, which can be viewed as intermediate between eobulloides and edita. Eoglobigerina edita is an intermediate member of the eobulloides-edita -spiralis lineage, which terminated in Zone P2 (see also Pearson, 1993).
Examinations of the holotypes (Plate 8: Figures 13-18, Plate 9: Figures 1-6) of Eoglobigerina hemisphaerica Morozova, E. theodosica Morozova, E. tetragona Morozova, and E. pentagona Morozova suggest that these are junior synonyms of edita Subbotina. These Morozova species are all characterized by having a weakly cancellate test and an elevated initial whorl, which places them within the edita plexus. The difference between these morphotypes is the elevation of the spire (high in hemisphaerica and pentagona, lower in theodosica and tetragona) and the number of chambers in the ultimate whorl (5½ in hemisphaerica, 5 in theodosica, Axli in pentagona, 4 in tetragona). The 5½-chambered, finely cancellate holotype of hemisphaerica has a distinctly elevated spiral side; Morozova (1961) drew attention to the "stepped nature" of the antepenultimate and penultimate whorls, which was said to serve to distinguish hemisphaerica from edita. We regard this as being within the range of variation of E. edita. [Olsson et al. 1999]

Catalog entries: Globigerina (Eoglobigerina) hemisphaerica;
Globigerina (Eoglobigerina) pentagona;
Globigerina (Eoglobigerina) tetragona;
Globigerina (Eoglobigerina) theodosica;
Globigerina edita;

Type images:

Short diagnosis: The species is characterized by a moderately high trochospiral test with 4½ to 5 (occasionally up to 7) globular chambers which increase gradually in size in the ultimate whorl, and a strongly lobulate peripheral margin. The aperture is a rounded umbilical to slightly extraumbilical aperture which is bordered by a narrow lip. The umbilicus is small but open to the previous chambers. The cancellate wall is weakly developed and spinose with numerous spine holes along the cancellate ridges. The overall size of the test is generally less than 250 um.

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: The species is characterized by a moderately high trochospiral test with 4½ to 5 (occasionally up to 7) globular chambers which increase gradually in size in the ultimate whorl, and a strongly lobulate peripheral margin. The aperture is a rounded umbilical to slightly extraumbilical aperture which is bordered by a narrow lip. The umbilicus is small but open to the previous chambers. The cancellate wall is weakly developed and spinose with numerous spine holes along the cancellate ridges. The overall size of the test is generally less than 250 um. [Olsson et al. 1999]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Spiroconvexaperture:Interiomarginal
umb chamber shape:Inflatedcoiling axis:Highperiphery:N/Aaperture border:N/A
sp chbr shape:Inflatedumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
umbilical or test sutures:Moderately depressedumb depth:Shallowwall texture:Smoothshell porosity:Microperforate: <1µm
spiral sutures:Moderately depresseddiameter mm:0.25width mm:-breadth mm:0.15
final-whorl chambers:4.5-5.0

Biogeography and Palaeobiology


Geographic distribution: Worldwide in high and low
latitudes (Figure 7). [Olsson et al. 1999]
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (1999)

Isotope paleobiology: No data. [Olsson et al. 1999]
Aze et al. 2011 ecogroup 3 - Open ocean thermocline. Based on light δ13C and relatively heavy δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Phylogenetic relations: This species evolved from Eoglobigerina eobulloides near the base of Zone Pa by an increase in the number of chambers in the last whorl and a slowing of the rate of growth of these chambers. In addition, there is a trend towards an elevated initial spire. An increase in the degree of spinosity is also evident in the evolution of E. edita. [Olsson et al. 1999]

Biostratigraphic distribution

Geological Range:
Notes: Zone Pa to Zone Pic; ? P2. [Olsson et al. 1999]
Last occurrence (top): within P1c subzone (62.60-63.90Ma, top in Danian stage). Data source: Olsson et al. 1999
First occurrence (base): within Pa zone (65.72-66.00Ma, base in Danian stage). Data source: Olsson et al. 1999

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 19

References:

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.


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Eoglobigerina edita compiled by the pforams@mikrotax project team viewed: 24-10-2017

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