pforams@mikrotax - Chiloguembelina wilcoxensis pforams@mikrotax - Chiloguembelina wilcoxensis

Chiloguembelina wilcoxensis

Classification: pf_cenozoic -> Guembelitrioidea -> Chiloguembelinidae -> Chiloguembelina -> Chiloguembelina wilcoxensis
Sister taxa: C. adriatica, C. cubensis, C. andreae, C. ototara ⟩⟨ C. parallela, C. trinitatensis, C. wilcoxensis, C. crinita ⟩⟨ C. subtriangularis, C. midwayensis, C. morsei, C. sp.


Citation: Chiloguembelina wilcoxensis (Cushman&Ponton 1932)
taxonomic rank: Species
Basionym: Guembelina wilcoxensis
Taxonomic discussion: The final chamber in adult Chiloguembelina wilcoxensis may be normalform to strongly kummerform. The aperture on the final chamber may be a symmetrical low to moderately high semicircular arch, centered on the chamber face and bordered by an equidimensional lip, or they may be slightly asymmetrical, off-centered on the final chamber face, and bordered by an inequidimensional lip that is slightly infolded on one side. The symmetrical shape and positioning of the aperture and equidimensional bordering lip on adult specimens of C. wilcoxensis are reminiscent of the Cretaceous Heterohelicidae. However, dissection of adult tests with symmetrical apertures in the center of the final chamber reveal that the apertures on pre-adult chambers are asymmetrical in position and shape and the bordering lip in infolded on one side. Apertural asymmetry in early ontogeny is taken to represent a primitive feature shared with the chiloguembelinid stock, whereas apertural symmetry in adult specimens is considered a derived character that first appeared in C. trinitatensis. Chiloguembelina wilcoxensis differs from this species by its larger less tapering test. [Olsson et al. 1999]

Catalog entries: Guembelina wilcoxensis

Type images:

Distinguishing features:
Parent taxon (Chiloguembelina): Test subtriangular in outline, biserial throughout or rarely with multiserial final chambers; aperture a simple arched opening at base of the final chamber, with a narrow rim on one margin and a broad collar or flange directed toward one of the flat sides of the test, lacking an infolded margin or internal plate. Rarely with multiple apertures.
This taxon: Test large, with broadly rounded periphery, rapid chamber size increase in the initial portion of the test. Aperture symmetrically centered, low-arched to semicircular with an equidimensional 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.


Character matrix
test outline:Subtriangularchamber arrangement:Biserialedge view:Equally biconvexaperture:Interiomarginal
sp chamber shape:Globularcoiling axis:N/Aperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:N/Aperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:N/Awall texture:Moderately pustuloseshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:2-2 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Phylogenetic relations

Although Beckmann (1957) suggested that C. wilcoxensis descended from C. crinita during the late Paleocene, it is more likely that C. wilcoxensis was derived from C. trinitatensis during the late Paleocene since C. wilcoxensis and C. trinitatensis are more similar morphologically and study of Caribbean DSDP Site 152 indicates that the first occurrence of the latter species is older than that of the former species (B. Huber, pers. observ., 1995). Both species have a similar pustulose wall texture which suggests that they are phylogenetically related. [Olsson et al. 1999]

Most likely ancestor: Chiloguembelina crinita - at confidence level 4 (out of 5). Data source: Olsson et al. 1999, f6.
Likely descendants: Chiloguembelina trinitatensis; plot with descendants

Biostratigraphic distribution

Geological Range:
Notes: Upper Paleocene Zone P4b through lower Eocene Zone E4. At middle latitude sites on the New Jersey coastal margin Liu and others (1997) recorded the HO of C. wilcoxensis in the middle of their Zone P6a (~Zone E2). For the southern high latitudes the LO of C. wilcoxensis was reported slightly earlier than at low latitudes, within middle Zone AP2 (~Zone P4b), and the extinction of this species marks the top of the Chiloguembelina wilcoxensis Zone (AE1) of Huber and Quille_ve_re_ (2005).
Last occurrence (top): in mid part of E4 zone (50% up, 53.6Ma, in Ypresian stage). Data source: Huber et al. 2006, f16.2
First occurrence (base): in mid part of P4b subzone (50% up, 59.2Ma, in Thanetian 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. 92


Beckmann, J. P. (1957). Chiloguembelina Loeblich and Tappan and related foraminifera from the Lower Tertiay of Trinidad, B.W.I. 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: 83-95. gs

Cushman, J. A. & Ponton, G. M. (1932a). An Eocene foraminiferal fauna of Wilcox age from Alabama. Contributions from the Cushman Laboratory for Foraminiferal Research. 8(3): 51-72. gs

Huber, B. T., Olsson, R. K. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene microperforate planktonic foraminifera (Jenkinsina, Cassigerinelloita, Chiloguembelina, Streptochilus, Zeauvigerina, Tenuitella, and Cassigerinella) and Problematica (Dipsidripella). In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 16): 461-508. gs O

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


Chiloguembelina wilcoxensis compiled by the pforams@mikrotax project team viewed: 17-7-2024

Taxon Search:
Advanced Search

Short stable page link: Go to to create a permanent copy of this page - citation notes

Add Comment

* Required information
Captcha Image
Powered by Commentics


No comments yet. Be the first!