Globorotaliaimitata Subbotina, 1953:206, holotype: pl. 16: fig. 14a-c; paratype: pl. 16: figs. 15a-16c [zone of rotaliform globorotaliids (Danian Stage), Kuban River, northern Caucasus].—Loeblich and Tappan, 1957a: 190, pl. 54:fig.8a-c [Zone P4, Vincentown Fm., New Jersey], pl. 59: fig. 5a-c [Zone P4, Aquia Fm., Maryland], pl. 63: fig. 3a-c [Zone P4, Velasco Fm., Mexico] [in part, not pl. 44:fig.3a-c, pl. 45:fig.6a-c, pl. 54: fig. 9a-c].—Olsson, 1960:46, pl. 9: figs. 7-9 [Zone P3b, Homerstown Fm., New Jersey]. [Olsson et al. 1999]
Taxonomic discussion: This is a distinctive species that is often overlooked because of its small size. It belongs to the perforate walled, inflated chamber lineage of planocompressa -imitata -ovalis. It also appears to have a phylogenetic link to G. australiformis (see "Discussion" under this species). The specimens illustrated as imitata by Blow (1979, pl. 81: figs. 8, 9, pl. 83: figs. 1,2, pl. 88:fig.5) are distinctly cancellate walled and do not belong to this species but probably belong to Praemurica. [Olsson et al. 1999]
Distinguishing features: Parent taxon (Globanomalina): Very low trochospiral; 5-6 chambers in final whorl; chamber-shape variable. Aperture interiomarginal, umbilical-extraumbilical, arch with narrow lip. Wall smooth, normally perforate, pustules in some species. This taxon: Test small. Final whorl with 4-4½ (rarely 5) inflated ovoid chambers. Aperture a high umbilical-extraumbilical arch with thin continuous lip.
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
Diagnostic characters: A small smooth-walled test with 4 to 4½, occasionally 5, inflated chambers in the ultimate whorl. The chambers are ovoid in shape with the long axis directed towards the umbilicus. In spiral and umbilical view the chambers are ovoid in shape with the long axis parallel to the coiling spire. The test walls are perforate throughout and the aperture is a high umbilical-extraumbilical arch that is bordered by a thin continuous lip. The wall is smooth in the adult chambers, but is covered with fine scattered to dense pustules in the early ontogenetic stages which possess anguloconical chambers. [Olsson et al. 1999]
Character matrix
test outline:
Ovate
chamber arrangement:
Trochospiral
edge view:
Planoconvex
aperture:
Umbilical-extraumbilical
sp chamber shape:
Inflated
coiling axis:
Low
periphery:
N/A
aperture border:
Thin lip
umb chbr shape:
Inflated
umbilicus:
Narrow
periph margin shape:
Moderately rounded
accessory apertures:
None
spiral sutures:
Moderately depressed
umb depth:
Deep
wall texture:
Smooth
shell porosity:
Finely Perforate: 1-2.5µm
umbilical or test sutures:
Moderately depressed
final-whorl chambers:
4-5
N.B. These characters are used for advanced search. N/A - not applicable
Biogeography and Palaeobiology
Geographic distributionKnown from the northern Caucasus, southeast India, and the Atlantic and Gulf of Mexico coastal plains. [Olsson et al. 1999]
Aze et al. 2011 summary: Northern Caucasus, S.E. India, Atlantic and Gulf of Mexico coastal plains; based on Olsson et al. (1999) Isotope paleobiologyNo data available. [Olsson et al. 1999] Aze et al. 2011 ecogroup 3 - Open ocean thermocline; based on comparison with other species of the genus. Phylogenetic relationsThis species probably evolved from Globanomalinaplanocompressa in Zone Pic. [Olsson et al. 1999]
Geological Range: Notes: Zone Pic to Zone P4. [Olsson et al. 1999] Last occurrence (top): near base of P5 zone (10% up, 57Ma, in Thanetian stage). Data source: Olsson et al. 1999, fig 5a First occurrence (base): in upper part of P1c subzone (60% up, 63.1Ma, in Danian stage). Data source: Olsson et al. 1999, fig 5a
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
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 42
References:
Loeblich, A. R. & Tappan, H. (1957b). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin . 215: 173-198. gs
Olsson, R. K. (1960). Foraminifera of late Cretaceous and earliest Tertiary age in the New Jersey Coastal Plain. Journal of Paleontology. 34(1): 1-58. gs
Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. (85): 1-252. gs
Subbotina, N. N. (1953). Foraminiferes fossiles d'URSS Globigerinidae, Globorotaliidae, Hantkeninidae. Bureau de Recherches Geologiques et Minieres. 2239: 1-144. gs
Globanomalina imitata compiled by the pforams@mikrotax project teamviewed: 11-2-2026
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holotype: G. imitata
