pforams@mikrotax - Heterohelix

pforams@mikrotax - Heterohelix pforams@mikrotax - Heterohelix

Heterohelix

Classification: pf_mesozoic -> Heterohelicidae -> Heterohelix
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)
			Heterohelix americana
			Heterohelix sp. Specimens which cannot be assigned to established species

Taxonomy

Citation: Heterohelix Ehrenberg 1843

taxonomic rank: Genus

Type species: Textilaria americana Ehrenberg, 1843

Taxonomic discussion: The name Heterohelix was for a long time used very widley, including most biserial heterohelicids. However, now it used only for the single species H. americana.

As noted by Frerichs and Gaskill (1978 p. 143), the type species of Heterohelix is Textilaria americana Ehrenberg, 1843 by original monotypy (hence Cushman's, 1927, p. 190, designation of Spiroplecta americana as the type of Heterohelix is invalid). Textilaria americana was first illustrated by Ehrenberg (1854, pl. 32 I, fig. 4a), and similar specimens were illustrated by Frerichs and Gaskill. The latter authors regarded Ehrenberg's pl. 32 I, figs. 13, 14 of Spiroplecta americana to be the microspheric generation of Heterohelix americana.

Original description: Cellulae primae nonnullis spirales. Tales formae forsan proprio generi addicendae sunt: Heterohelix.

Approximate translation (by JRY 2019 - with assistance from google translate)
Sometimes the first chambers are spirally arranged. These forms can perhaps be assigned their own genus: Heterohelix.
N.B. This brief description appears after the description of Textilaria americana and is used to distinguish this form from similar biserial forams without the initial spiral portion.

Entries in the Catalog of original descriptions: Heterohelix

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: Initially planispiral, final 1 or 2 pairs of chambers subtriangular with a short blunt spine.

Morphology:

Test with early chambers in a tiny planispiral coil, at least in the microspheric generation, later with biserially arranged inflated to globular chambers, final one to two pairs of chambers subtriangular in outline with a short blunt spine at the outer angle of the chamber, sutures depressed; wall calcareous, perforate, ornamented with numerous fine longitudinal striae; aperture a high narrow arch at the base of the last chamber.

Geological Range:
Last occurrence (top): at top of W. archaeocretacea zone (100% up, 93.5Ma, in Turonian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within W. archaeocretacea zone (93.52-94.03Ma, base in Cenomanian stage). Data source: Total of ranges 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:

Cushman, J. A. (1927g). The designation of some genotypes in the foraminifera. Contributions from the Cushman Laboratory for Foraminiferal Research. 3(4): 188-190. gs

Ehrenberg, C. G. (1843b). Verbreitung und Einfluss des mikroscopischen Lebens in Süd- und Nord Amerika. Bericht uber die zu Bekanntmachung geeigneten Verhandlungen der Koniglichen Preussische Akademie der Wissenschaften zu Berlin. 1841: 291-446. gs

Ehrenberg, C. G. (1854). Mikrogeologie: Das Erden und Felsen schaffende Wirken des unsichtbar kleinen selbständigen Lebens auf der Erde. Leopold Voss, Leipzig. 1-374. gs

Frerichs, W. E. & Gaskill, C. H. (1978). Textilaria americana Ehrenberg: Type species of Heterohelix. Journal of Foraminiferal Research. 8(2): 143-146. gs

Loeblich, A. R. & Tappan, H. (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York. 1-1059. gs

Heterohelix compiled by the pforams@mikrotax project team viewed: 9-10-2024

Taxon Search:

Advanced Search

Short stable page link: https://mikrotax.org/pforams/index.php?id=110283 Go to Archive.is to create a permanent copy of this page - citation notes

Add Comment

Comments

No comments yet. Be the first!