pforams@mikrotax - Hantkenina singanoae pforams@mikrotax - Hantkenina singanoae

Hantkenina singanoae

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


Citation: Hantkenina singanoae Pearson & Coxall, in Coxall & Pearson 2006
taxonomic rank: Species
Basionym: Hantkenina singanoae
Synonyms: See Pearson & Coxall (2014) for an extended syonymy list and for discussion the alternative taxonomies proposed by Rögl & Egger (2012) and by Coccioni & Bancalà (2012)
Taxonomic discussion: The species is erected to include a range of diverse morphologies that appear transitional between Clavigerinella caucasica and H. mexicana. The Clavigerinella caucasica -Hantkenina singanoae interface is not clear-cut because the transition between the two is gradual. However, we favor placing singanoae in Hantkenina rather than Clavigerinella because it possesses proto-tubulospines and/or terminal nubs, structures that are considered homologous to tubulospines. No such structures are present in Clavigerinella. [Coxall & Pearson 2006]

Catalog entries: Hantkenina singanoae, Hantkenina gohrbandti

Type images:

Distinguishing features:
Parent taxon (Hantkenina): Final chambers with tubulospines
This taxon: Final chambers very elongate with rudimentary terminal cylindrical extensions, but lacking true tubulospines. 4-5 chambers in the final whorl.

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.


Planispiral or pseudo- planispiral, laterally compressed, 4-5 rapidly expanding chambers in the final whorl; final chamber, and up to three of the preceding chambers, radially elongate, at least one of these ending in either a terminal nub or cylindrical projection (‘proto-tubulospine’); proto-tubulospines are smooth and distinctly porous (although pore density may be reduced at the distal ends) in contrast to the true tubulospines of H. mexicana and subsequent species, which are usually imperforate; distal chamber ends can be inclined in an anterior, posterior or dorso-ventral direction and pseudo-tubulospines are commonly bent; aperture is a high equatorial arch with a smooth, broad lip; lips of relict apertures are commonly observed along the sutures of the final whorl; sutures are shallow and usually curved in a posterior direction.

Wall type:
The wall is layered and perforate, with a smooth or weakly cancellate surface

Maximum diameter of holotype (excluding proto-tubulospines) 0.63 mm.

Character matrix
test outline:Stellatechamber arrangement:Planispiraledge view:Compressedaperture:Equatorial
sp chamber shape:Subtriangularcoiling axis:N/Aperiphery:Tubulospinesaperture border:Thick lip
umb chbr shape:Subtriangularumbilicus:Wideperiph margin shape:Subangularaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Shallowwall texture:Smoothshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:4-5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

So far only found in Tanzania and Austria. [Coxall & Pearson 2006]
Aze et al. 2011 summary: Found only in Tanzania and Austria so far; based on Coxall & Pearson (2006)

Isotope paleobiology
No data available. [Coxall & Pearson 2006]
Aze et al. 2011 ecogroup 3 - Open ocean thermocline; based on comparison with other species of the genus.

Phylogenetic relations
Hantkenina singanoae evolved from C. caucasica by constriction of the terminal chamber ends. This transitional form evolved into Hantkenina mexicana by further elongation of the protuberance and reduction in pore density to form elongated, nonporous tubulospines of Hantkenina proper. [Coxall & Pearson 2006]

Most likely ancestor: Clavigerinella caucasica - at confidence level 0 (out of 5). Data source: Coxall & Pearson (2006) fig 8.1.
Likely descendants: Hantkenina mexicana; plot with descendants

Biostratigraphic distribution

Geological Range:
Notes: Restricted to uppermost lower Eocene Zone E7 and basal E8, overlapping slightly with Hantkenina mexicana. [Coxall & Pearson 2006]
Last occurrence (top): near base of E9 zone (10% up, 43.8Ma, in Lutetian stage). Data source: Wade et al. (2011), fig. 6
First occurrence (base): near top of E8 zone (90% up, 44Ma, in Lutetian stage). Data source: Coxall & Pearson (2006), fig. 8.1

Plot of occurrence data:

Primary source for this page: Coxall & Pearson 2006 - Eocene Atlas, chap. 8, p. 252


Coccioni, R. & Bancala, C. (2012). New insights into the pattern, timing, and duration of the evolutionary origin of the foraminiferal genus Hantkenina. Revue de Micropaléontologie. 55: 71-81. 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., Huber, B. T. & Pearson, P. N. (2003). Origin and morphology of the Eocene planktonic foraminifera Hantkenina. Journal of Foraminiferal Research. 33: 237-261. gs

Pearson, P. N. & Coxall, H. K. (2014). Origin of the Eocene planktonic foraminifer Hantkenina by gradual evolution. Palaeontology. 57(2): 243-267. gs

Pearson, P. N. et al. (2004). Paleogene and Cretaceous sediment cores from the Kilwa and Lindi areas of coastal Tanzania: Tanzania Drilling Project Sites 1–5. Journal of African Earth Sciences. 39: 25-62. gs

Rögl, F. & Egger, H. (2011). A new planktonic foraminifera species (Hantkenina gohrbandti nov. spec.) from the middle Eocene of the northwestern Tethys (Mattsee, Austria). Austrian Journal of Earth Sciences. 104: 4-14. gs


Hantkenina singanoae compiled by the pforams@mikrotax project team viewed: 3-3-2024

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