pforams@mikrotax - Planoheterohelix sphenoides pforams@mikrotax - Planoheterohelix sphenoides

Planoheterohelix sphenoides

Classification: pf_mesozoic -> Heterohelicidae -> Planoheterohelix -> Planoheterohelix sphenoides
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 sphenoides (Masters, 1976)
Rank: Species
Basionym: Heterohelix sphenoides Masters, 1976
Taxonomic discussion: Moved here to Planoheterohelix, since the species clearly does not correspond to the revised generic concept of Heterohelix [editor's comment - JRY 2020]

Type images:

Original description: Early part of test broadly flaring with globular chambers, later with more lentil shaped chambers and subparallel sides; finely to coarsely costate surface texture. Aperture a high, narrow arch bordered by a narrow, imperforate lip. Chamber sutures imperforate, depressed, convex toward later chambers; zig-zag median suture twice the width fo the other sutures.

Entries in the Catalog of original descriptions: Heterohelix sphenoides

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:Weakly depressedumb depth:N/Awall texture:Finely costateshell porosity:Microperforate: <1µm
umbilical or test sutures:Weakly 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 D. asymetrica zone (84.19-86.71Ma, top in Santonian stage). Data source: [copied from Chronos database]
First occurrence (base): within D. concavata zone (86.71-89.91Ma, base in Turonian stage). Data source: [copied from Chronos database]

Plot of range and occurrence data:


Masters, B. A. (1976). Planktonic foraminifera from the Upper Cretaceous Selma group, Alabama. Journal of Paleontology. 50(2): 318-330. gs

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


Planoheterohelix sphenoides compiled by the pforams@mikrotax project team viewed: 29-3-2023

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Comments (1)

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The use of double quote for the genus does not imply the use of brackets for the authority. H. sphenoides is the type species of Planulitella Georgescu, 2010 (a subjective junior synonym of Heterohelix in the opinion of Mikrotax, isn't it?).


Jeremy Young (UK)

Thanks - I've corrected the brackets in the citation now. The genera in the Heterohelicidae are in a state of flux so that is a matter for Brian, but we are puting the new genera etc into the catalog.

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