pforams@mikrotax - Planoheterohelix

Planoheterohelix

Classification: pf_mesozoic -> Heterohelicidae -> Planoheterohelix
Sister taxa: Heterohelix, Spiroplecta ⟩⟨ Braunella, Hendersonites, Huberella, Laeviheterohelix, Planoheterohelix, Protoheterohelix, Pseudoguembelina, Pseudotextularia ⟩⟨ Planoglobulina, Ventilabrella, Gublerina, Praegublerina, Sigalia, Racemiguembelina ⟩⟨ Lunatriella, Rectoguembelina, Zeauvigerina

Daughter taxa (time control age-window is: 0-800Ma)
			Planoheterohelix globulosa
			Planoheterohelix moremani
			Planoheterohelix olssoni
			Planoheterohelix papula
			Planoheterohelix paraglobulosa
			Planoheterohelix planata
			Planoheterohelix postmoremani
			Planoheterohelix praenuttallii
			Planoheterohelix reussi
			Planoheterohelix rumseyensis
			species here provisionally placed in Planohetorohelix
			Planoheterohelix labellosa
			Planoheterohelix sphenoides
			Planoheterohelix stenopos
			Planoheterohelix vistulaensis
			Planoheterohelix sp. Specimens which cannot be assigned to established species

ODP Leg 174-160~b.JPG
TDP-761~b.JPG
Pessagno 1967 pl87 05 8-9.JPG

Taxonomy

Citation: Planoheterohelix Georgescu & Huber, 2009

Rank: Genus

Synonyms:

Globoheterohelix (the type species G. paraglobulosa is now placed in Planoheterohelix)

Original description: Description. Test is biserial throughout. Proloculus is small and followed by larger second chamber. Chambers are subglobular to globular in early portion of test and often reniform in adult. Periphery is broadly rounded. Aperture is a low- to medium-high arch situated at base of last-formed chamber; it is bordered by two symmetrically developed flanges. Chamber surface is smooth or with fine longitudinal costae in earlier species and completely costate in evolved ones. Test wall is calcitic, hyaline, microperforate to finely perforate. Pores are situated in intercostal spaces or they might penetrate and interrupt costae.

Entries in the Catalog of original descriptions: Planoheterohelix, Globoheterohelix

Distinguishing features:
Parent taxon (Heterohelicidae): Aperture symmetrical, ranging from a low slit to a high arch at the base of the final chamber, becoming terminal in uniserial taxa.
This taxon: Biserial throughout, aperture symmetrically positioned, wall texture costate.

Emended description:

Test is moderate in size and has globular to subglobular chambers that are biserially arranged throughout and become reniform in some species. Proloculus diameters range from 12–72 mm and subsequent chambers increase in size at varying rates. Aperture is a symmetrical semicircular arch at the base of the final chamber. Sutures are depressed and form at an oblique angle to the central axis. Apertural structures vary but typically consist of symmetrical flanges or an imperforate apertural lip. Test wall is calcitic, ornamented with fine, continuous costae and is microperforate to finely perforate (pore diameter 0.6–3.2 µm).

Morphology:

Test is moderate in size and has globular to subglobular chambers that are biserially arranged throughout and become reniform in some species. Proloculus diameters range from 12–72 µm and subsequent chambers increase in size at varying rates. Aperture is a symmetrical semicircular arch at the base of the final chamber. Sutures are depressed and form at an oblique angle to the central axis. Apertural structures vary but typically consist of symmetrical flanges or an imperforate apertural lip. Test wall is calcitic, ornamented with fine, continuous costae and is microperforate to finely perforate (pore diameter 0.6–3.2 µm).

Wall type:

Size:

Geological Range:
Last occurrence (top): near top of Maastrichtian Stage (94% up, 66.4Ma, in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Cenomanian Stage (67% up, 96.1Ma, in Cenomanian stage). Data source: Total of range of species in this 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
Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: Heterohelicidae

References:

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

Planoheterohelix compiled by the pforams@mikrotax project team viewed: 8-12-2022

Taxon Search:

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Short stable page link: https://mikrotax.org/pforams/index.php?id=110399 Go to Archive.is to create a permanent copy of this page - citation notes

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