pforams@mikrotax - Planoheterohelix stenopos pforams@mikrotax - Planoheterohelix stenopos

Planoheterohelix stenopos

Classification: pf_mesozoic -> Heterohelicidae -> Planoheterohelix -> Planoheterohelix stenopos
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 stenopos (Masters 1976)
Rank: Species
Basionym: Heterohelix stenopos 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]

Provisionally placed in "Heterohelix" pending taxonomic revision of Late Cretaceous biserial taxa.

Type images:

Original description: Test biserial, laterally compressed, un-keeled; elongate; minimal increase in width throughout; profile slightly lobate. Chambers 16-17 in number; only slightly inflated; each succeeding chamber but little larger than previous one, wider than deep. Pores of fine to moderate diameter in rows between costae. Costae discontinuous, of moderate width and height; conforming to the curvature of the chamber as viewed from the side. Aperture a low, narrow arch with an imperforate lip, which increases in width toward contact with previous chamber. The sides of the relict apertural lips expressed as depressed triangular areas between adjacent chambers. Sutures straight, depressed, normal to edge, imperforate.

Entries in the Catalog of original descriptions: Heterohelix stenopos

Character matrix
test outline:Subtriangularchamber arrangement:Biserialedge view:Compressedaperture:Interiomarginal
sp chamber shape:Subrectangularcoiling axis:N/Aperiphery:N/Aaperture border:Thin flange
umb chbr shape:Subrectangularumbilicus:N/Aperiph margin shape:Moderately roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:N/Awall texture:Smoothshell porosity:Microperforate: <1┬Ám
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 Campanian Stage (72.05-83.64Ma, top in Campanian stage). Data source:
First occurrence (base): within Santonian Stage (83.64-86.26Ma, base in Santonian stage). Data source:

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


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

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