Hantkenina compressa


Classification: pf_cenozoic -> smooth non-spinose -> Hantkeninidae -> Hantkenina -> Hantkenina compressa
Sister taxa: H. nanggulanensis, H. alabamensis, H. primitiva, H. compressa, H. australis, H. dumblei, H. lehneri, H. liebusi, H. mexicana, H. singanoae, H. sp.,

Taxonomy

Citation: Hantkenina compressa Parr 1947
Rank: Species
Basionym: Hantkenina compressa
Synonyms:
Taxonomic discussion: Hantkenina compressa is intermediate in morphology between H. dumblei and H. alabamensis and overlaps stratigraphically with them both. It thus bridges the supposed evolutionary gap (Blow, 1979) between middle and late Eocene hantkeninids. This morphotype is common in deep sea and land-outcropping pelagic sections but has previously been referred to H. dumblei, H. cf. dumblei or H. alabamensis, which has had the effect of artificially extending the stratigraphic range of H. dumblei into the upper Eocene and lowering the range of H. alabamensis within the middle Eocene. Recognition of H. compressa demands stricter definitions of the latter two species and increases their biostratigraphic utility. The species intergrades with H. alabamensis in the upper Eocene. We have included specimens that are transitional to H. alabamensis to show the range of variability permitted to Hantkenina compressa (Pl.8.6, Figs. 10, 14, 21). The holotype of H. brevispina Cushman, 1924, which is described as having much shorter and stouter tubulospines than other hantkeninids, resembles Parr’s (1947) illustrations of H. compressa and may be a prior synonym. The holotype of H. brevispina, however, is missing from the USNM collections and thus unavailable for comparison. We suggest, therefore, that H. brevispina should be suppressed and H. compressa adopted as the valid name for these morphotypes. [Coxall & Pearson 2006]

Catalog entries: Hantkenina brevispina;
Hantkenina compressa;

Type images:

Short diagnosis: Final chambers triangular, with nearly continuous peripheral outline; tubulospines in the trans-sutural position and with forward-inclined orientation.

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


Diagnostic characters: Hantkenina compressa differs from H. dumblei in the trans-sutural position and more forward-inclined orientation of the tubulospines, often angular periphery and less rapid increase in chamber height in the adult whorl. It is distinguished from H. alabamensis in lacking the sub-tangential adult tubulospines and in having more laterally compressed chambers. As in H. alabamensis, the final 2-3 tubulospines of H. compressa are in contact with the posterior wall of the adjacent chambers, but this is not as pronounced as in the former. [Coxall & Pearson 2006]

Wall type: Smooth, perforate and probably nonspinose; tubulospines imperforate, smooth or with fine striations. [Coxall & Pearson 2006]

Test morphology: Planispiral, biumbilicate, somewhat compressed laterally, although individual chambers are slightly inflated; 5-6 closely appressed chambers in the final whorl, increasing rapidly in size as added, sub-triangular or polygonal in shape; adult chambers extend into a hollow tubulospine; peripheral outline continuous, lobed or slightly angular; aperture is an elongated narrow equatorial arch flaring into lateral lobes, bordered by a wide flaring lip; sutures straight to slightly sigmoidal; tubulospines straight, long and slender or short and triangular, arising sharply from the supporting chamber, positioned at the anterior chamber edge, spanning the suture between adjacent chambers, in contact with the posterior wall of the next youngest chamber along a short portion of the length at the base, inclined forward in the direction of coiling, distal ends taper to points, often with a small coronet structure (Ramsay, 1962), sometimes opening from the axial canal into a small terminal aperture. [Coxall & Pearson 2006]

Size: Maximum diameter (excluding tubulospines) 400-700 µm. [Coxall & Pearson 2006]

Character matrix

test outline:Lobatechamber arrangement:Planispiraledge view:Compressedaperture:Terminal
umb chamber shape:Subtriangularcoiling axis:N/Aperiphery:Tubulospinesaperture border:Thick lip
sp chbr shape:Subtriangularumbilicus:Wideperiph margin shape:Subangularaccessory apertures:None
umbilical or test sutures:Moderately depressedumb depth:Shallowwall texture:Smoothshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:Moderately depresseddiameter mm:400-700width mm:breadth mm:
final-whorl chambers:5.0-6.0

Biogeography and Palaeobiology


Geographic distribution: Worldwide at low to mid latitudes, also New Zealand. [Coxall & Pearson 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Coxall & Pearson (2006)

Isotope paleobiology: Hantkenina compressa from Zone E12 registers relatively low ∂18O and high ∂13C, similar to coexisting Morozovelloides and Acarinina (Coxall and others, 2000), indicating that it lived in warm waters of the surface mixed layer. There is no ∂13C -enrichment trend with increasing test size. [Coxall & Pearson 2006]
Aze et al. 2011 ecogroup 2 - Open ocean mixed-layer tropical/subtropical, without symbionts. Based on δ13C lighter than species with symbionts; also with relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): Coxall & Pearson (2006)

Phylogenetic relations: Evolved from H. dumblei by a reduction in chamber height and tightening of the planispiral coiling. [Coxall & Pearson 2006]

Most likely ancestor: Hantkenina dumblei - at confidence level 4 (out of 5). Data source: Coxall & Pearson (2006) fig 8.1.

Biostratigraphic distribution

Geological Range:
Notes: Mid Zone E11 to the Eocene/Oligocene boundary. [Coxall & Pearson 2006]
Last occurrence (top): at top of E16 zone (100% up, 33.9Ma, in Priabonian stage). Data source: Coxall & Pearson (2006) fig 8.1
First occurrence (base): in upper part of E11 zone (60% up, 41Ma, in Lutetian stage). Data source: Coxall & Pearson (2006), fig. 8.1

Plot of occurrence data:

Primary source for this page: Coxall & Pearson 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 8, p. 233

References:

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, 1413 pp.

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

Coccioni, R., (1988). The genera Hantkenina and Cribrohantkenina (Foraminifera) in the Massignano section (Ancona, Italy),: Ancona II. In: Premoli Silva, I., Coccioni, R. and Montanari, A. (Editors), The Eocene-Oligocene Boundary in the Marche-Umbria Basin (Italy). International Subcommission on Paleogene Stratigraphy, Special Publication II, pp. 81-96.

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.

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.

Cushman, J.A. & Jarvis, P.W., (1929). New foraminifera from Trinidad. Contributions from the Cushman Laboratory for Foraminiferal Research, 5: 6-17.

Cushman, J.A., (1924). A new genus of Eocene foraminifera. Proceedings of the United States National Museum, 66(2567): 1-4.

Parr, W.J., (1947). An Australian Record of the Foraminiferal Genus Hantkenina. Proceedings of the Royal Society of Victoria, LVIII(I-II): 45-47.

Raju, D.S.N., (1968). Eocene-Oligocene planktonic foraminiferal biostratigraphy of Cauvery Basin, South India. Geological Society of India, 2: 286-299.

Ramsay, W.R., (1962). Hantkeninidae in the Tertiary rocks of Tanganyika. Contributions from the Cushman Foundation for Foraminiferal Research, 13: 78-89.

Rey, M., (1939). Distribution stratigraphique des Hantkenina dans le Nummulitique du Rharb (Maroc). Bulletin de la Société Géologique de France, 5: 321-341.

Weinzierl, L.L. & Applin, E.R., (1929). The Claiborne Formation on the Coastal Domes. Journal of Paleontology, 3(4): 384-410.


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Hantkenina compressa compiled by the pforams@mikrotax project team viewed: 17-12-2017

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