nmn

Rugoglobigerina hexacamerata


Classification: pf_mesozoic -> Rugoglobigerinidae -> Rugoglobigerina -> Rugoglobigerina hexacamerata
Sister taxa: R. hexacamerata, R. macrocephala, R. milamensis, R. pennyi, R. rugosa, R. spinosa, R. sp.,

Taxonomy

Citation: Rugoglobigerina hexacamerata Brönnimann, 1952
Rank: Species
Basionym: Rugoglobigerina reicheli hexacamerata
Synonyms: Rugoglobigerina lobatula; Globotruncana (Rugoglobigerina) hexacamerata subhexacamerata
Taxonomic discussion: The subspecies hexacamerata and pustulata are so closely related that at first they were lumped together. The more detailed investigation proved that the two types can be separated, not only on account of the difference in the number of adult chambers but also by the large, subcircular umbilicus and by the predominant meridional ornamentation in the last whorl of R. reicheli hexacamerata. From the morphologically similar subspecies pennyi of the rugosa group (0.4-0.425 mm.), it is separated by the smaller size and the more delicate ornamentation. [copied from Chronos database]

Type images:

Original description: The small to medium-sized test is a low trochoidal spiral with 6 chambers in the adult. The umbilical side, characterized by a very large, deep, almost circular umbilicus, exhibits fragments of the covering plate along the truncate edges of the chambers. The slightly depressed spiral side shows about 2 whorls. The well-separated subglobular and truncate chambers increase rather slowly in size. The end chamber can be smaller than the penultimate one and is frequently displaced toward the umbilical side. The deep sutures are straight and occasionally slightly curved. The arcuate aperture of the end chamber is large and apparently provided with a minute liplike projection. Those of the preceding chambers are not known. The walls are thick, and the surface is coarsely rugose. The surface of about two-thirds of the chambers of the last volution shows the meridional pattern, whereas that of the earlier chambers is irregularly hispid. Only dextrally coiling individuals were counted.

Entries in the Catalog of original descriptions: Rugoglobigerina reicheli hexacamerata, Rugoglobigerina lobatula, Globotruncana (Rugoglobigerina) hexacamerata subhexacamerata

Geological Range:
Last occurrence (top): within A. mayaroensis zone (67.30-69.18Ma, top in Maastrichtian stage). Data source: [copied from Chronos database]
First occurrence (base): within Campanian Stage (72.05-83.64Ma, base in Campanian stage). Data source: [copied from Chronos database]

Plot of range and occurrence data:

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:-aperture:Umbilical
sp chamber shape:Globularcoiling axis:Very lowperiphery:N/Aaperture border:Tegilla
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:Infralaminal
spiral sutures:Strongly depressedumb depth:Shallowwall texture:Meridional costellaeshell porosity:-
umbilical or test sutures:Strongly depressedfinal-whorl chambers:5.5-6.5 N.B. These characters are used for advanced search. N/A - not applicable

References:

Brönnimann, P. (1952c). Globigerinidae from the Upper Cretaceous (Cenomanian-Maestrichtian) of Trinidad, B. W. I. Bulletins of American Paleontology. 34(140): 1-70. gs

Pessagno, E. A. (1967). Upper Cretaceous planktonic foraminifera from the western Gulf Coastal Plain. Palaeontographica Americana. 5: 245-445. gs V O

Robaszynski, F., Caron, M., Gonzales Donoso, J. M., Wonders, A. A. H. & the European Working Group on Planktonic Foraminifera (1984). Atlas of Late Cretaceous globotruncanids. Revue de Micropaléontologie. 26(3-4): 145-305. gs

Smith, C. C. & Pessagno, E. A. (1973). Planktonic foraminifera and stratigraphy of the Corsicana formation (Maestrichtian) North-central Texas. Cushman Foundation for Foraminiferal Research, Special Publication. 12: 1-67. gs


logo

Rugoglobigerina hexacamerata compiled by the pforams@mikrotax project team viewed: 20-10-2020

Taxon Search:
Advanced Search

Short stable page link: http://mikrotax.org/pforams/index.php?id=110500 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics