pforams@mikrotax - Hantkenina pforams@mikrotax - Hantkenina

Hantkenina


Classification: pf_cenozoic -> Hantkeninidae -> Hantkenina
Sister taxa: Cribrohantkenina, Hantkenina, Clavigerinella
Daughter taxa (time control age-window is: 0-800Ma)
final chambers (sub)triangular
Hantkenina nanggulanensis
Final 1-2 chambers globular, test large (up to 0.47 mm)
Hantkenina alabamensis
Final 1-2 chambers laterally inflated, coiling compact and involute, tubulospines forward leaning.
Hantkenina primitiva
Like H. compressa but tubulospines absent on early adult chambers and test generally smaller.
Hantkenina compressa
Final chambers triangular, with nearly continuous peripheral outline; tubulospines in the trans-sutural position and with forward-inclined orientation.
Hantkenina australis
Species showing features of H. dumblei and H. compressa, but unique in having posteriorly recurved tubulospines.
Hantkenina dumblei
Final chambers triangular, with nearly continuous peripheral outline, tubulospines in anterior (near sutural) position.
final chambers elongate
Hantkenina lehneri
Final chambers elongate with tubulospines in forward position; peripheral outline distinctly stellate. 5-6 chambers in the final whorl.
Hantkenina liebusi
Like H. mexicana but with more compressed test, less stellate peripheral outline, and tubulospines in a more forward position. 4½-6 chambers in the final whorl.
Hantkenina mexicana
Final chambers elongate; tubulospines centrally positioned; peripheral outline distinctly stellate. 4-5 chambers in the final whorl.
Hantkenina singanoae
Final chambers very elongate with rudimentary terminal cylindrical extensions, but lacking true tubulospines. 4-5 chambers in the final whorl.
Hantkenina sp.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Hantkenina Cushman, 1925
taxonomic rank: Genus
Type species: Hantkenina alabamensis Cushman, 1924.
Synonyms:
Taxonomic discussion: We regard Hantkenina as a monophyletic genus and do not support Blow’s (1979) view that the early middle Eocene and late middle Eocene to late Eocene species were separately derived. Although the shells are compressed and planispiral, the earliest morphotypes (H. singanoae and H. mexicana) show signs of asymmetry in aperture shape and in the distribution of pre-adult whorls on one or other side of the shell. This feature, which is also seen in the sister genus Clavigerinella, testifies to a trochospiral ancestry.
[Coxall & Pearson 2006]

Catalog entries: Hantkenina

Distinguishing features:
Parent taxon (Hantkeninidae): Planispiral, wall smooth
This taxon: Final chambers with tubulospines

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
They are being edited as the site is developed and comments on them are especially welcome.

Description


Morphology:
Planispiral, biumbilicate or showing a subtly raised spiral side and very shallow umbilicus; 4-7 chambers in the final whorl; chambers rounded in the early stages, adult chambers radially elongated, triangular, polygonal or spherical, laterally compressed or highly inflated; some or all of the adult chambers extend into hollow non-porous tubulospines, of variable length, shape and orientation, or, in the case of H. singanoae n. sp., the chambers possess a distinct terminal nub or porous “proto-tubulospine”; peripheral outline (excluding tubulospines) varies from stellate, with deep incisions between chambers, to angular, smooth-continuous or gently lobed; the aperture is a single equatorial arch bordered by a distinctive lip of variable width, symmetrical or slightly asymmetrical.
[Coxall & Pearson 2006]

Wall type:
Smooth, normal perforate, probably nonspinose. [Coxall & Pearson 2006]

Biogeography and Palaeobiology


Isotope paleobiology

Coxall et al. 2000 inferred from stable isotopes that "the hantkeninids originated in a deep-water oxygen-minimum environment, but migrated into fully oxygenated near-surface waters as global temperatures decreased and water-column stratification declined. This change in depth ecology coincided with pronounced morphological evolution, involving changes in chamber shape and degree of inflation, and modification of the primary aperture. These developments are considered to be adaptations to a near-surface habitat"

Phylogenetic relations
Hantkenina evolved gradually from Clavigerinella caucasica in the latest early Eocene (Coxall and others, 2003). It gave rise to Cribrohantkenina in the late Eocene and the entire family went extinct at the Eocene/Oligocene boundary (33.7 Ma). [Coxall & Pearson 2006]

Most likely ancestor: Clavigerinella - at confidence level 4 (out of 5). Data source: Coxall & Pearson 2006; .
Likely descendants: Cribrohantkenina; plot with descendants

Biostratigraphic distribution

Geological Range:
Last occurrence (top): at top of E16 zone (100% up, 33.9Ma, in Priabonian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within E8 zone (43.85-45.72Ma, base in Lutetian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

Primary source for this page: Coxall & Pearson 2006 - Eocene Atlas, chap. 8, p. 229

References:

Bermudez, P. J. (1937b). Nuevas especies de Foraminiferos del Eoceno de Cuba. Memorias de la Sociedad Cubana de Historia Natural “Felipe Poey”. 11: 137-150. gs

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs

Brönnimann, P. (1950b). The Genus Hantkenina Cushman in Trinidad and Barbados, B. W. I. Journal of Paleontology. 24(4): 397-420. gs

Coxall, H. K. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of the Hantkeninidae (Clavigerinella, Hantkenina and Cribrohantkenina). In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 8): 213-256. gs O

Coxall, H. K., Pearson, P. N., Shackleton, N. J. & Hall, M. A. (2000). Hantkeninid depth adaptation: An evolving life strategy in a changing ocean. Geology. 28: 87-90. gs

Coxall, H. K., Huber, B. T. & Pearson, P. N. (2003). Origin and morphology of the Eocene planktonic foraminifera Hantkenina. Journal of Foraminiferal Research. 33: 237-261. gs

Cushman, J. A. (1925a). A new genus of Eocene foraminifera. Proceedings of the United States National Museum. 66(30): 1-4. gs

Thalmann, H. E. (1942). Foraminiferal genus Hantkenina and its subgenera. American Journal of Science. 240: 809-820. gs


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Hantkenina compiled by the pforams@mikrotax project team viewed: 10-12-2024

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Comments (1)

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Hi

Hantkenina was described in Cushman, J. A. (1925). A new genus of Eocene Foraminifera. Proceedings of the United States National Museum. 66[1926](30): 1-4. Published January 23, 1925 (see p. VI of Table of contents): https://www.biodiversitylibrary.org/item/32809#page/12/

Loeblich & Tappan gave 1924 as the date of publication, Ellis & Messina 1925.

Four new species were also described in the same publication:

Hantkenina alabamensis Cushman, 1925 † (original description)

Hantkenina brevispina Cushman, 1925 † (original description)

Hantkenina longispina Cushman, 1925 † accepted as Hantkenina liebusi Shokhina, 1937 † (original description)

Happy new year!

François

Hantkenina mexicana Cushman, 1925 † (original description)