pforams@mikrotax - Planoheterohelix planata

pforams@mikrotax - Planoheterohelix planata pforams@mikrotax - Planoheterohelix planata

Planoheterohelix planata

Classification: pf_mesozoic -> Heterohelicidae -> Planoheterohelix -> Planoheterohelix planata
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.

DSDP Site 511-160~a.JPG
ODP Site 690-160~b.JPG
DSDP Site 511-160~b.JPG
ODP Site 690-160~a.JPG
ODP Leg 174-160~a.JPG
Pessagno 1967 pl89 06-7.JPG

Taxonomy

Citation: Planoheterohelix planata (Cushman, 1938)

Rank: Species

Basionym: Guembelina planata

Synonyms: Guembelina distorta; Heterohelix pachymarginata

Type images:

holotype: G. planata
holotype: G. planata
holotype: G. planata

Original description: Test compressed, about 1½ times as long as broad, rapidly tapering with the greatest breadth formed by the last pair of chambers, periphery slightly keeled in the early portion, in the remainder deeply indentate; chambers broader than high throughout, somewhat compressed, in the adult portion separated by depressed triangular areas; sutures distinctly depressed, somewhat curved; wall smooth, finely perforate, the perforations tending to be in longitudinal lines; aperture high, arched, with distinct lateral flanges running out onto the preceding chamber.

Entries in the Catalog of original descriptions: Guembelina planata, Guembelina distorta, Heterohelix pachymarginata

Emended description:

Georgescu, Saupe & Huber, 2009, p.402: "The test is biserial throughout. The earliest chambers are globular then subrectangular; the later chambers may be reniform in some specimens. Chambers increase gradually in size as added. Sutures are distinct, straight and depressed and slightly oblique to the test axis of growth. The two rows of alternating chambers may diverge in the adult stages of some specimens, but no central area is consistently developed. The periphery of the test is rounded. The aperture is situated at the base of the last-formed chamber and has a medium high to high arch. It is bordered by two small flanges, which are rarely rimmed. Chamber surface is ornamented with fine costae that are 1.8 to 2.5 microns thick. The test wall is microperforate with pore diameters ranging from 0.6 to 0.8 microns. Pores are distributed in the spaces between the costae or can penetrate through the costae." [copied from Chronos database]

Character matrix
test outline: Subtriangular chamber arrangement: Biserial edge view: Compressed aperture: Interiomarginal
sp chamber shape: Inflated coiling axis: N/A periphery: N/A aperture border: Thin flange
umb chbr shape: Inflated umbilicus: N/A periph margin shape: Moderately rounded accessory apertures: None
spiral sutures: Moderately depressed umb depth: N/A wall texture: Finely costate shell porosity:
umbilical or test sutures: Moderately depressed final-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 A. mayaroensis zone (67.30-69.18Ma, top in Maastrichtian stage). Data source: [copied from Chronos database]
First occurrence (base): within D. asymetrica zone (84.19-86.71Ma, base in Coniacian stage). Data source: [copied from Chronos database]

Plot of range and occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Taxon plotted: Planoheterohelix planata, synonyms included - Guembelina pseudotessera; Heterohelix distorta; Heterohelix pachymarginata; Heterohelix planata; Heterohelix rumseyensis; Heterohelix stenopos;
See also space-time plot :: Samples map :: Parent: Planoheterohelix

References:

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

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

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

Taxon Search:

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AphiaID: 1034800 Nomenclatural data on WoRMS
Short stables page link: https://mikrotax.org/pforams/index.php?id=110406 Go to Archive.is to create a permanent copy of this page - citation notes

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test outline:	Subtriangular	chamber arrangement:	Biserial	edge view:	Compressed	aperture:	Interiomarginal
sp chamber shape:	Inflated	coiling axis:	N/A	periphery:	N/A	aperture border:	Thin flange
umb chbr shape:	Inflated	umbilicus:	N/A	periph margin shape:	Moderately rounded	accessory apertures:	None
spiral sutures:	Moderately depressed	umb depth:	N/A	wall texture:	Finely costate	shell porosity:
umbilical or test sutures:	Moderately depressed	final-whorl chambers:	2.0-2.0	N.B. These characters are used for advanced search. N/A - not applicable