Globoconusa victori


Classification: pf_cenozoic -> Guembelitrioidea -> Guembelitriidae -> Globoconusa -> Globoconusa victori
Sister taxa: G. victori, G. daubjergensis, G. sp.

Taxonomy

Citation: Globoconusa victori Koutsoukos 2014
Rank: Species
Synonyms:
Taxonomic discussion: Remarks. The species is characterized by its small trilobate form with a distinctive test surface. It is distinguished from its ancestral species, Globoconusa daubjergensis, in having a compact, trilobate form with a flattened to somewhat depressed spiral side, rather than a high trochospire; a highly inflated ultimate chamber occupying from ½–⅔ of test size; and a distinct extra-umbilical-umbilical (rather than umbilical) aperture. Intermediate specimens occur with overall similar trilobate morphology, but with a slightly higher spire and an aperture varying from more extraumbilical and slit-like (see Olsson et al., 1999, pl. 64, fig. 6) to slightly extraumbical but arched, close to Gl. daubjergensis (Fig. 8.8; see also Morozova et al., 1967, pl. 5, figs. 6a–c). [Koutsoukos 2014]

Catalog entries: Globoconusa victori

Type images:

Distinguishing features: Like G. daubjergensis but with a more compact trilobate test with a much larger highly inflated last chamber, and a flattened or somewhat depressed profile. 

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


Wall type: Test microperforate, pores widely dispersed, with a distinct hispid/pustulose surface, covered by scattered to abundant blunt to more commonly sharp-pointed small pustules (enlarged view in Fig. 7.1b). [Koutsoukos 2014]

Morphology: Test small; low, compact trochospiral, tightly coiled; spiral side slightly flattened to somewhat depressed, slightly concave in outline, umbilical side inflated, and thickness , ⅔ of the diameter. Last whorl composed of 3–3½ globular chambers increasing rapidly in size; ultimate chamber is characteristically highly inflated (globular), commonly occupying from ½–⅔ of test size (~40–60%). Equatorial outline is typically trilobate. Axial periphery broadly rounded. Sutures are straight to slightly curved, depressed on umbilical side, and nearly flush/ indistinct (in the early ontogenetic stage) to slightly depressed on the spiral side. Primary aperture a very low, elongate arch or low-arched slit, extraumbilical-umbilical in position.  [Koutsoukos 2014]

Size: 12-180 µm

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Globularcoiling axis:Low-moderateperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Deepwall texture:Moderately pustuloseshell porosity:Microperforate: <1µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:3.0-3.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Isotope paleobiology: Currently unrecorded [Koutsoukos 2014]

Phylogenetic relations: Phylogenetic relationships. The species evolved from Gl. daubjergensis (Brönnimann) within Zone P1c through the development of a more compact trilobate test with a much larger highly inflated last chamber, and by the sharp decrease of spiral height to produce a flattened or somewhat depressed profile.  [Koutsoukos 2014]

Most likely ancestor: Globoconusa daubjergensis - at confidence level 3 (out of 5). Data source: Koutsoukos 2014, fig16.

Biostratigraphic distribution

Geological Range:
Notes: The total range is unknown because the core is short and at its base Zone P1c unconformably overlies Zone P1a sediments. [Koutsoukos 2014]
Last occurrence (top): within P1c subzone (62.60-63.90Ma, top in Danian stage). Data source: Koutsoukos 2014, fig16
First occurrence (base): within P1c subzone (62.60-63.90Ma, base in Danian stage). Data source: Koutsoukos 2014, fig16

Plot of occurrence data:

Primary source for this page: Koutsoukos 2014

References:

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

Brotzen, F. & Pozaryska, K. (1961). Foraminiferes du Paleocene et de l'Eocene inferieur en Pologne septentrionale; remarques paleogeographiques. Revue de Micropaléontologie. 4: 155-166. gs

Koutsoukos, E. (2014). Phenotypic plasticity, speciation, and phylogeny in Early Danian planktic foraminifera. Journal of Foraminiferal Research. 44: 109-142. gs

Morozova, V. G., Kozhevnikova, G. E. & Kuryleva, A. M. (1967). Datsko-Paleotsenovye Raznofatsial'nye Otlozheniya Kopet-Daga I. Metody Ikh korrelyatsii po foraminiferam [Danian-Paleocene heterofacial deposits of Kopet-Dag and methods of their correlation according to the foraminifers]. Trudy Geologicheskiy Institut Akademiya Nauk SSSR. 157: 1-208. gs

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


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Globoconusa victori compiled by the pforams@mikrotax project team viewed: 15-6-2021

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