Hantkeninidae


Classification: pf_cenozoic -> smooth non-spinose -> Hantkeninidae
Sister taxa: Hantkeninidae, Hedbergellidae,
Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Eocene lineage of Hantkeninids with clavate final chambers; wall smooth, planispiral



The most prominent feature of Hantkenina is the presence of tubulospines, which distinguish it from the ancestral genus Clavigerinella. Tubulospines also occur in closely related Cribrohantkenina, which differs from Hantkenina in having a multiple areal aperture system. The Cretaceous genus Schackoina, which is the only other planktonic foraminiferal genus to possess tubulospines, is readily distinguished from Hantkenina by having a microperforate wall, fewer chambers and much smaller test size (0.63-1.50 mm).


Taxonomy

Citation: Hantkeninidae Cushman 1927
Rank: Family
Type species: Hantkenina Cushman, 1924
Taxonomic discussion: Cushman’s original broad description of the Family Hantkeninidae was such that almost any smaller foraminifer with planispiral coiling could be placed within it, and previous classifications have variously included Hastigerina, Pseudohastigerina and Schackoina in addition to Hantkenina (e.g., Cushman, 1948; Bolli and others, 1957). Although it is now known that these genera are unrelated, it is desirable to retain the Family in emended form to unite the middle to upper Eocene genera Clavigerinella, Hantkenina and Cribrohantkenina, which constitute a clearly defined monophyletic clade with a distinctive wall texture (Coxall and others, 2003; Hemleben and Olsson, Chapter 4, this volume). Although all species in this Family possess planispirally coiled shells, early members, e.g., Clavigerinella spp., Hantkenina singanoae n. sp. and H. mexicana, show some asymmetry (pseudo-planispirality) in side and apertural views, whereas later forms, e.g., H. dumblei, H. alabamensis and Cribrohantkenina inflata, possess a fully planispiral shell with strong symmetry across the mid-line. It is noteworthy that although it ultimately had a trochospiral ancestor, the complex multiple aperture system of Cribrohantkenina is usually bilaterally symmetrical across the equatorial plane, while being very variable between individuals, suggesting truly planispiral morphogenetic programming. [Coxall & Pearson 2006]

Catalog entries: Hantkeninidae [not in catalog yet]

Type images:

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.

Description


Wall type: Normal perforate, Clavigerinella-type wall, smooth or weakly cancellate; some species possibly sparsely spinose. [Coxall & Pearson 2006]

Test morphology: Planispiral or ‘pseudo-planispiral’ coiling; early chambers rounded, becoming digitate/clavate, triangular, polygonal, or spherical in the adult stages, laterally compressed or highly inflated; primary aperture a single narrow, symmetrical equatorial arch, bordered by an imperforate lip, accompanied or replaced by one or more additional areal apertures in the final 1-3 chambers (Cribrohantkenina); adult chambers of Hantkenina and Cribrohantkenina extend into a pronounced terminal nub or well-developed hollow tubulospine, projecting radially or at a low angle with respect to the chamber periphery in the direction of coiling. [Coxall & Pearson 2006]

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within Priabonian Stage (33.89-37.75Ma, top in Priabonian stage). Data source: Total of range of species in this database
First occurrence (base): within Ypresian Stage (47.84-55.96Ma, base in Ypresian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Coxall & Pearson 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 8, p. 214

References:

Coxall, H.K. & Pearson, P.N., (2006). Taxonomy, biostratigraphy, and phylogeny of the Hantkeninidae (Clavigerinella, Hantkenina and Cribrohantkenina). In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Allen Press, Lawrence, Kansas, pp. 213-256.

Cushman, J.A., (1927). Some characteristic Mexican fossil foraminifera. Journal of Paleontology, 1(2): 147-172.


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Hantkeninidae compiled by the pforams@mikrotax project team viewed: 22-8-2017

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