CATALOG OF ORIGINAL DESCRIPTIONS: Planoheterohelix Georgescu & Huber, 2009

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: pf_cat -> P -> Planoheterohelix
Other pages this level: Palaeoglobigerina, Paracostellagerina, Paragloborotalia, Paraspiroplecta, Parasubbotina, Parathalmanninella, Paraticinella, Parkerina, Parvularugoglobigerina, Pearsonites, Pessagnoina, Phanerostomum, Planoglobanomalina, Planoglobulina, Planoheterohelix, Planomalina, Planorotalites, Planulina, Planulitella, Plummerita, Plummerita (Radotruncana), Polskanella, Polyperibola, Porticulasphaera, Postrugoglobigerina, Praeglobotruncana, Praeglobotruncana (Clavihedbergella), Praeglobotruncana (Falsomarginotruncana), Praegublerina, Praehedbergella, > >>

Daughter taxa: (blue => in age window 0-800Ma)
= Planoheterohelix postmoremani
= Planoheterohelix praenuttallii

Planoheterohelix

Citation: Planoheterohelix Georgescu & Huber, 2009
Rank: Genus
Type species: Planoheterohelix postmoremani Georgescu & Huber, 2009

Current identification/main database link: Planoheterohelix Georgescu & Huber, 2009


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. 

Etymology: The Latin prefix plano (= plane) is added to the pre-existing genus name Heterohelix.

Extra details from original publication
Remarks. Planoheterohelix is the first genus of Cretaceous serial planktic foraminifers with completely symmetrical tests as seen in edge view. Test symmetry differentiates Planoheterohelix from its ancestor Protoheterohelix, which displays asymmetrical tests or periapertural structures. Late Albian–Cenomanian species of Planoheterohelix have a microperforate test wall (0.5–0.9 mm); finely perforate species are known only from higher stratigraphic levels (Turonian–lower Maastrichtian).

Species included:
The latter three species occur at higher stratigraphical levels (Coniacian–lower Maastrichtian).

Stratigraphic range. Middle Cenomanian–lower Maastrichtian.

Geographic distribution. Cosmopolitan.

References:

Georgescu, M. D. & Huber, B. T. (2009). Early evolution of the Cretaceous serial planktic foraminifera (late Albian-Cenomanian). Journal of Foraminiferal Research. 39: 335-360. gs


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Planoheterohelix compiled by the pforams@mikrotax project team viewed: 27-2-2020

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