pforams@mikrotax - Hantkeninidae

Citation: Hantkeninidae Cushman 1927

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]

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

Most likely ancestor: Globigerinidae - at confidence level 3 (out of 5). Data source: The ancestor of Clavigerinella is now thought to be Subbotina.

Biostratigraphic distribution

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): near top of Ypresian Stage (85% up, 49.1Ma, in Ypresian stage). Data source: Total of range of species in this database

Primary source for this page: Coxall & Pearson 2006 - Eocene Atlas, chap. 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., Olsson, R.K., Hemleben, C., Huber, B.T. and Berggren, W.A. (Editors), Atlas of Eocene Planktonic Foraminifera. Cushman Foundation Special Publication. Allen Press, Lawrence, Kansas, pp. 213-256. GS

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

Daughter taxa: (blue => in age window 0-800Ma)		Granddaughter taxa
	Cribrohantkenina Final chambers with tubulospines and areal apertures	C. inflata C. sp.
	Hantkenina Final chambers with tubulospines	H. nanggulanensis H. alabamensis H. primitiva H. compressa H. australis H. dumblei H. lehneri H. liebusi H. mexicana H. singanoae H. sp.
	Clavigerinella Final chambers clavate.	C. akersi C. caucasica C. colombiana C. eocanica C. jarvisi C. sp.

Hantkeninidae

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

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