nmn

Rugoglobigerina spinosa


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

Taxonomy

Citation: Rugoglobigerina spinosa Masters 1993
Rank: Species
Basionym: Rugoglobigerina spinosa
Taxonomic discussion: Bronnimann (1952) recognized the spinose morphotype in his paratype series of Rugoglobigerina reicheli pustulata, a rarely used name. An examination of the types in the U.S. National Museum shows that his holotype does not exhibit the spinose periphery that most of the paratypes do but shows the characteristic morphology of and is regarded as a junior synonym of R. rugosa. Therefore, the name pustulata is not available for this distinctive form and a new name is necessary. Subsequent workers generally have confused pseudospines (R. spinosa) with tubulospines (P. reicheli). A. pseudospine, as used here, is a modified pustule, a solid structure in which the length tends to exceed the diameter; whereas, tubulospines are by definition hollow extensions to the chamber. Additionally, distinction can be made on chamber shape: subspherical throughout (R. spinosa) vs. radially elongate to mixed (P. reicheli). Although diagenesis can be a factor in the preserved length of the pseudospine, species recognition is always possible because no other Rugoglobigerina exhibits a peripheral zone of pseudospines. Rugoglobigerina rugose (Plummer) has well developed costellae over the entire surface which never break up into pseudospines at the periphery as occurs in R. spinosa. The costellate ridges in R. rugosa and others of the genus can be discontinuous, breaking up into shorter segments, but never develop a peripheral zone of pseudospines. Some paratypes of El-Naggars Rugoglobigerina arwae may rightly belong to R. spinosa, but the holotype of his species lacks the spines along the periphery. [copied from Chronos database]

Type images:

Original description: Test a flat trochospire, early whorl often depressed below final whorl; equatorial periphery lobate and axial periphery broadly rounded, the outlines of each interrupted by short pseudospines. Chambers 4.5 to typically 5 well inflated chambers in final whorl; meridionally oriented costellae generally are not well developed and tend to break up at the periphery to become pseudospines or may be replaced altogether by pustules and pseudospines. Aperture a low, interiomarginal, umbilical-extraumbilical arch. A tegillum covers a moderately wide, shallow umbilicus. Sutures depressed, straight and radial on both sides. Surface entirely perforate except for the tegillum, costellae and pseudospines. Variation. Toward the periphery, the length of the costellae tends to become shorter and then rapidly breaks up into a broad band consisting of pustules which grade into peripheral pseudospines (PI. 4, Fig. 1). The costellae tend to be best developed on the sides of the chambers (PI. 4, Figs. 3, 7), but even here they may be replaced by pustules (PI. 4, Figs. 4, 6). The zones of costellae and of pseudospines vary in width (PI. 4, Figs. 2, 5, 8). The pseudospines also vary in length, but are typically longest at the periphery when well preserved. Other features are generally stable.

Entries in the Catalog of original descriptions: Rugoglobigerina spinosa

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 A. mayaroensis zone (67.30-69.18Ma, base in Maastrichtian stage). Data source: [copied from Chronos database]

Plot of occurrence data:

Dec 2017 - Plotting of Neptune data has been re-enabled on the Mesozoic pages following revision of the age-models in Neptune. The data is, however, still very sparse for the Early Cretaceous

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Rugoglobigerina

    Character matrix

    test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical
    sp chamber shape:Globularcoiling axis:Very lowperiphery:N/Aaperture border:Tegilla
    umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:Infralaminal
    spiral sutures:Strongly depressedumb depth:Deepwall texture:Meridional costellaeshell porosity:Finely Perforate: 1-2.5µm
    umbilical or test sutures:Strongly depressedfinal-whorl chambers:4.5-5.0 N.B. These characters are used for advanced search. N/A - not applicable

    References:

    Masters, B. A. (1993). Re-evaluation of the species and subspecies of the genus Plummerita Brönnimann and a new species of Rugoglobigerina Brönnimann (Foraminiferida). Journal of Foraminiferal Research. 23: 267-274. gs


    logo

    Rugoglobigerina spinosa compiled by the pforams@mikrotax project team viewed: 17-10-2019

    Taxon Search:
    Advanced Search

    Short stable page link: http://mikrotax.org/pforams/index.php?id=110507 Go to Archive.is to create a permanent copy of this page - citation notes



    Comments (0)

    No comments yet. Be the first!

    Add Comment

    * Required information
    1000
    Captcha Image
    Powered by Commentics