pforams@mikrotax - Planoheterohelix moremani pforams@mikrotax - Planoheterohelix moremani

Planoheterohelix moremani

Classification: pf_mesozoic -> Heterohelicidae -> Planoheterohelix -> Planoheterohelix moremani
Sister taxa: P. globulosa, P. moremani, P. olssoni, P. papula, P. paraglobulosa, P. planata, P. postmoremani, P. praenuttallii, P. reussi, P. rumseyensis ⟩⟨ P. labellosa, P. sphenoides, P. stenopos, P. vistulaensis, P. sp.


Citation: Planoheterohelix moremani (Cushman, 1938)
Rank: Species
Basionym: Guembelina moremani
Synonyms: Guembelina boliviniformis
Taxonomic discussion: Multiserial growth may be present as a terminal stage. Georgescu & Huber. 2009, p.81: "The holotype (USNM 307959), which is deposited in the Cushman Collection, Smithsonian Institution, Washington, D.C., shows 21 chambers (Pl. 4, figs. 1-2). Elsewhere such specimens with numerous chambers and a more elongate appearance are rare, being reported only by Huber and others (1999) from the western North Atlantic (Blake Plateau, ODP Leg 171B). Most of the paratypes (USNM 307960-307962) display tests consisting of 17 to 19 chambers." [copied from Chronos database]

Type images:

Original description: Slender test with up to 18 chambers that subglobular to slightly reniform, or deeper than wide.--Huber "Test elongate, 2½-3 times as long as broad, gradually tapering throughout, only slightly enlarging in the later portion, periphery distinctly indented throughout; chambers globular, often slightly irregular and occasionally with one developed at the side in the adult; sutures distinct and depressed throughout; wall smooth, finely perforate; aperture, a high arched opening at the inner margin of the last-formed chamber, with a slight lip which may reach forward at the sides onto the previously formed chamber. 

Entries in the Catalog of original descriptions: Guembelina moremani, Guembelina boliviniformis

Emended description:

Georgescu & Huber. 2009, p.81: "Test is slender and symmetrical in edge view. It consists of 14-21 chambers, which are biserially arranged throughout, subglobose in the juvenile portion, and elongate and oblique to the axis of growth in the adult stage. The proloculus (10.8-16.4 microns) is smaller than the second chamber. Sutures are distinct, straight and depressed, and oblique to the test axis of growth. Aperture is a medium-high arch at the base of the last-formed chamber. Two delicate, symmetrically developed periapertural flanges border the aperture. Chamber surface is smooth but aligned pustules and rarer incipient costae can be occasionally observed on the earlier part of the test. Test wall is calcitic, hyaline and microperforate; pore diameter ranges 0.5-0.7 microns." [copied from Chronos database]

Character matrix
test outline:Elongatechamber arrangement:Biserialedge view:Compressedaperture:Interiomarginal
sp chamber shape:Inflatedcoiling axis:N/Aperiphery:N/Aaperture border:Thin flange
umb chbr shape:Inflatedumbilicus:N/Aperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:N/Awall texture:Smoothshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:2.0-2.0 N.B. These characters are used for advanced search. N/A - not applicable

Geological Range:
Last occurrence (top): within H. helvetica zone (92.56-93.52Ma, top in Turonian stage). Data source: [copied from Chronos database]
First occurrence (base): within T. reicheli zone (95.94-96.08Ma, base in Cenomanian stage). Data source: [copied from Chronos database]

Plot of range and occurrence data:


Cushman, J. A. (1938). Cretaceous species of Guembelina and related genera. Contributions from the Cushman Laboratory for Foraminiferal Research. 14: 2-28. gs V O

Falzoni, F., Petrizzo, M. R., Jenkyns, H. C., Gale, A. S. & Tsikos, H. (2016). Planktonic foraminiferal biostratigraphy and assemblage composition across the Cenomanian–Turonian boundary interval at Clot Chevalier (Vocontian Basin, SE France). Cretaceous Research. 59: 69-97. gs

Nederbragt, A. J. (1991). Late Cretaceous biostratigraphy and development of Heterohelicidae (planktic foraminifera). Micropaleontology. 37: 329-372. gs

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


Planoheterohelix moremani compiled by the pforams@mikrotax project team viewed: 2-4-2023

Taxon Search:
Advanced Search
AphiaID: 1034738 Nomenclatural data on WoRMS
Short stables page link: Go to 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
Captcha Image
Powered by Commentics