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Laeviheterohelix reniformis


Classification: pf_mesozoic -> Heterohelicidae -> Laeviheterohelix -> Laeviheterohelix reniformis
Sister taxa: L. dentata, L. flabelliformis, L. glabrans, L. pulchra, L. reniformis, L. turgida, L. sp.

Taxonomy

Citation: Laeviheterohelix reniformis (Marie, 1941)
Rank: Species
Basionym: Ventilabrella reniformis

Type images:

Original description: Test à partie initiale réduite et effilée, composée de loges nettement croissantes, suivies dans l'adulte de loges croissantes, presque globuleuses et assez régulières à la périphérie des flancs, nettement allongées et reniformes à leur intérieur. Surface très finement striée longitudinalement.

Translation: Test showing a reduced and fringed initial part, with chambers increasing sharply in size as added; mature chambers enlarging as added, almost globular and fairly regular at the periphery of the sides, sharply elongated and reniform in their internal part. Surface finely striated longitudinally.

Entries in the Catalog of original descriptions: Ventilabrella reniformis


Emended description: Test size ranges from 210 to 306 microns in length (n = 6) and consists of 10 to 14 chambers that are biserially arranged in the earlier portion of the test and may become multichambered in final growth stage. Globular early chambers become reniform later in ontogeny. Proloculus size ranges from 15 to 25 microns in diameter (n = 5); early chambers increase gradually in size and then more rapidly later, becoming fan-shaped in side view. In edge view, tests generally remain compressed throughout ontogeny. Sutures are depressed and oblique to the central axis, and they widen to create a flattened indentation of the intercameral area on the later chambers. Aperture is a symmetrical, high-arch at the base of the final chamber, with symmetrical apertural flanges and an imperforate margin. Test wall is calcitic and hyaline, and the surface absent of costae. Early-formed chambers are smooth, whereas later chambers are ornamented with distinct, well-developed pore mounds that are randomly distributed over the test. Pores (0.6 to 0.8 microns in diameter, n = 5) are microperforate and pore mound rims are 2.2 to 3.3 microns (n = 5) in thickness. [copied from Chronos database]

Most likely ancestor: Laeviheterohelix pulchra - at confidence level 1 (out of 5). Data source: .

Geological Range:
Last occurrence (top): within Campanian Stage (72.05-83.64Ma, top in Campanian stage). Data source: [copied from Chronos database]
First occurrence (base): within H. helvetica zone (92.56-93.52Ma, base in Turonian stage). Data source: [copied from Chronos database]

Plot of range and occurrence data:

Character matrix

test outline:Palmatechamber arrangement:Multiserialedge view:Compressedaperture:Interiomarginal
sp chamber shape:Reniformcoiling axis:N/Aperiphery:N/Aaperture border:Thin lip
umb chbr shape:Reniformumbilicus:N/Aperiph margin shape:N/Aaccessory apertures:None
spiral sutures:Strongly depressedumb depth:N/Awall texture:Pore moundsshell porosity:Microperforate: <1µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:2.0-2.0 N.B. These characters are used for advanced search. N/A - not applicable

References:

Haynes, S., Huber, B. T. & MacLeod, K. G. (2015). Evolution and phylogeny of mid-Cretaceous (Albian-Coniacian) biserial planktic foraminifera. Journal of Foraminiferal Research. 44: 42-81. gs

Marie, P. (1941). Les foraminiferes de la craie a Belemnitella mucronata du Bassin de Paris. Mémoires du Muséum National d'Histoire naturelle. 12: 1-296. gs V O


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Laeviheterohelix reniformis compiled by the pforams@mikrotax project team viewed: 7-3-2021

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Short stable page link: https://mikrotax.org/pforams/index.php?id=110305 Go to Archive.is to create a permanent copy of this page - citation notes



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