Globigerinatheka euganea


Classification: pf_cenozoic -> spinose -> Globigerinidae -> Globigerinatheka -> Globigerinatheka euganea
Sister taxa: G. barri, G. curryi, G. euganea, G. index, G. korotkovi, G. kugleri, G. luterbacheri, G. mexicana, G. semiinvoluta, G. subconglobata, G. tropicalis,

Taxonomy

Citation: Globigerinatheka euganea Proto Decima and Bolli 1970
Rank: Species
Basionym: Globigerinatheka euganea
Synonyms:
Taxonomic discussion: At first sight G. euganea looks similar to Cushman’s original drawing of the G. mexicana
holotype, as redrawn by Blow and Saito (1968a). However, the SEM photographs of the mexicana holotype clearly show that the two species are not conspecific. [Premoli Silva et al. 2006]

Catalog entries: Globigerinatheka euganea;

Type images:

Short diagnosis: Globigerinatheka euganea has a compact, spherical test, with small, numerous secondary apertures in some specimens. It differs from G. curryi by having a more compact test, a tighter inner coil and more numerous and smaller secondary apertures. It differs from G. luterbacheri by having a more spherical test and less depressed sutures; it differs from beckmanni by less numerous, slightly larger secondary apertures, rarely recorded along the inner spire, and by the absence of areal openings.

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: Globigerinatheka euganea has a compact, spherical test, with small, numerous secondary apertures in some specimens. It differs from G. curryi by having a more compact test, a tighter inner coil and more numerous and smaller secondary apertures. It differs from G. luterbacheri by having a more spherical test and less depressed sutures; it differs from beckmanni by less numerous, slightly larger secondary apertures, rarely recorded along the inner spire, and by the absence of areal openings. [Premoli Silva et al. 2006]

Wall type: Spinose, cancellate, with rather dense pores, about 8 µm in diameter. [Premoli Silva et al. 2006]

Test morphology: Test almost spherical, mainly 2 to possibly 2½ early whorls coiled in a low trochospire consisting of four to six inflated chambers; chambers initially increase very slowly in size as they are added, then more rapidly, becoming more globular; the last 3 chambers, which increase very rapidly in size, are streptospirally coiled with the last chamber tending to be hemispherical and covering the umbilicus of previous whorls; the last chamber may be of the same size as the penultimate one or larger; sutures distinct, weakly depressed in the earlier whorl becoming clearly depressed in the intermediate whorls, tending to be less depressed between the last chambers; primary aperture covered in the adult stage; two to three, occasionally four small arched to subcircular secondary apertures along the base of the last chamber at the junctions of previous chambers, that may be covered by small bullae. [Premoli Silva et al. 2006]

Size: Maximum diameter of holotype 0.53 mm. [Premoli Silva et al. 2006]

Character matrix

test outline:Circularcoiling axis:Lowchamber arrangement:Trochospiralumbilicus:Narrow
edge view:Equally biconvexumbilical or test sutures:Moderately depressedspiral sutures:Moderately depressedshell porosity:Finely Perforate: 1-2.5
wall texture:Spinoseaperture:Umbilicalaperture border:N/Aaccessory apertures:Sutural
periphery:N/Aumb chamber shape:Globularsp chbr shape:Globularperiph margin shape:Broadly rounded
umb depth:Deepdiameter mm:0.23width mm:breadth mm:
final-whorl chambers:3.0-4.0

Biogeography and Palaeobiology


Geographic distribution: Low to mid-latitudes. Large specimens mainly in tropical regions or warmer mid latitudes. [Premoli Silva et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Premoli Silva et al. (2006)

Isotope paleobiology: No data available. [Premoli Silva et al. 2006]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy δ13C and relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Phylogenetic relations: According to Bolli (1972), G. euganea is the intermediate member of the curryi - euganea - beckmanni lineage. [Premoli Silva et al. 2006]

Biostratigraphic distribution

Geological Range:
Notes: Globigerinatheka euganea has a short stratigraphic range, from the upper part of Zone E10 to mid Zone E12. [Premoli Silva et al. 2006]
Last occurrence (top): within E12 zone (39.97-40.40Ma, top in Bartonian stage). Data source: Eocene Atlas
First occurrence (base): within E10 zone (41.89-43.23Ma, base in Lutetian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Premoli Silva et al. 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 7, p. 180

References:

Baumann, P., (1970). Mikropalaentologische und stratigraphische Untersuchungen der obereozaenen-oligozaenen Scaglia im zentralen Apennin (Italien). Eclogae Geologicae Helvetiae, 63: 1133-1211.

Beckmann, J.P., (1953). Die Foraminiferen der Oceanic Formation (Eocaen-Oligocaen) von Barbados, Kl. Antillen. Eclogae Geologicae Helvetiae, 46: 301-412.

Blow, W.H. & Saito, T., (1968). The morphology and taxonomy of Globigerina mexicana Cushman, 1925. Micropaleontology, 14(3): 357-360.

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.

Bolli, H.M., (1972). The genus Globigerinatheka Bronnimann. Journal of Foraminiferal Research, 2(3): 109-136.

Brönnimann, P., (1952). Globigerinoita and Globigerinatheka, new genera from the Tertiary of Trinidad, B.W.I. Cushman Foundation for Foraminiferal Research, Special Publication, 3(1): 25-28.

Cushman, J.A., (1925). New foraminifera from the Upper Eocene of Mexico. Contributions from the Cushman Foundation for Foraminiferal Reseach, 1(1): 4-9.

Cushman, J.A., (1927). Some characteristic Mexican fossil foraminifera. Journal of Paleontology, 1(2): 147-172.

Loeblich, A.R., Jr. & Tappan, H., (1957). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera, U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, D.C., pp. 173-198.

Premoli Silva, I.; Wade, B.S. & Pearson, P.N., (2006). Taxonomy, biostratigraphy, and phylogeny of Globigerinatheka and Orbulinoides. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Allen Press, Lawrence, Kansas, pp. 169-212.

Proto Decima, F. & Bolli, H.M., (1970). Evolution and variability of Orbulinoides beckmanni (Saito). Eclogae Geologicae Helvetiae, 63(3): 883-905.

Pujol, C., (1983). Cenozoic planktonic foraminiferal biostratigraphy of the South-Western Atlantic (Rio Grande Rise): Deep Sea Drilling Project Leg 72. Initial Reports of the Deep Sea Drilling Project, 72: 623-673.

Saito, T., (1962). Eocene planktonic foraminifera from Hahajima (Hillsborough Island). Trans. Proc. Pal. Soc. Japan, 1(45): 209-225.

Todd, R. & Low, D., (1960). Smaller foraminifera from Eniwetok drill hole. U.S. Geological Survey Professional Paper, 260-x: 799-861.

Toumarkine, M., (1975). Middle and Late Eocene planktonic foraminifera from the northwestern Pacific Ocean: Leg 32 of the Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project, 32: 735-751.

Toumarkine, M., (1978). Planktonic foraminiferal biostratigraphy of the Paleogene of Sites 360 to 364 and the Neogene of Sites 362A, 363 and 364 Leg 40,. Initial Reports of the Deep Sea Drilling Project, 40: 679-721.

Toumarkine, M., (1983). Les Foraminifères planctoniques de l’Eocène moyen et supérieur des régions tropicales à temperées chaudes. PhD Thesis, Université Pierre et Marie Curie, Paris 6, 83-05, 1-219 pp.


Globigerinatheka euganea compiled by the pforams@mikrotax project team viewed: 29-5-2017

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