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
Hantkenina Cushman, 1924:1. Type species Hantkeninaalabamensis.
Hantkenina (Sporohantkenina) Bermúdez, 1937:151. Type species Hantkeninabrevispina.
Hantkenina (Aragonella) Thalmann, 1942:811, 813. Type species Hantkeninamexicana.
Hantkenina (Applinella) Thalmann, 1942:812-814. Type species Hantkeninadumblei.
Hantkenina (Hantkeninella) Brönnimann, 1950:399. Type species Hantkeninaprimitiva.
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]
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
Wall type: Smooth, normal perforate, probably nonspinose. [Coxall & Pearson 2006] 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]
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 Clavigerinellacaucasica 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]
Geological Range: Last occurrence (top): at top of Priabonian Stage (100% up, 33.9Ma, in Priabonian stage). Data source: Total of range of species in this database First occurrence (base): in upper part of Lutetian Stage (57% up, 44Ma, in Lutetian stage). Data source: Total of range of species in this database
Plot of 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: Hantkeninidae
Primary source for this page: Coxall & Pearson 2006 - Eocene Atlas, chap. 8, p. 229
References:
Bermudez, P. J. (1937). Nuevas especies de Foraminiferos del Eoceno de Cuba. Memorias de la Sociedad Cubana de Historia Natural. 11: +143-+. gsVO
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. gsVO
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. (1924a). 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. gsVO
Hantkenina compiled by the pforams@mikrotax project teamviewed: 25-9-2021
