pforams@mikrotax - Hantkenina singanoae

pforams@mikrotax - Hantkenina singanoae <title>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.

Eocene_Atlas_pl08-13_fig11-12-14.jpg
Eocene_Atlas_pl08-13_fig6-9.jpg
Eocene_Atlas_pl08-13_fig10-15.jpg
Eocene_Atlas_pl08-13_fig17.jpg

Taxonomy

Citation: Hantkenina singanoae Pearson & Coxall, in Coxall & Pearson 2006

Rank: Species

Basionym: Hantkenina singanoae

Synonyms:

“Clavigerinella-Hantkenina transition” Coxall and others, 2003:250, pl. 6: figs. 3, 16 [lower middle Eocene, Helvetikum Section, Buntmergelserie, Austria, Gohrbandt (1967) sample 64/1-36/4b].
transitional Hantkenina sp. Pearson and others, 2004:37, pl.2: figs. 18-21 [Zone E7, TDP Site 2, Tanzania].
Hantkenina gohrbandti Rögl & Egger 2011 [according to Pearson & Coxall 2014]

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)

Variants:

Hantkenina singanoae type 1 of Pearson & Coxall (2014) - specimens with a terminal constriction or ‘nub’.
Hantkenina singanoae type 2 of Pearson & Coxall (2014) - specimens with long, slender proto-tubulospines.

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:

holotype: H. singanoae

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.

Description

Emended description:

Morphology:

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

Size:

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

Character matrix
test outline: Stellate chamber arrangement: Planispiral edge view: Compressed aperture: Equatorial
sp chamber shape: Subtriangular coiling axis: N/A periphery: Tubulospines aperture border: Thick lip
umb chbr shape: Subtriangular umbilicus: Wide periph margin shape: Subangular accessory apertures: None
spiral sutures: Moderately depressed umb depth: Shallow wall texture: Smooth shell porosity: Finely Perforate: 1-2.5µm
umbilical or test sutures: Moderately depressed final-whorl chambers: 4.0-5.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Similar species

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:

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
(NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Hantkenina

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

References:

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 V 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 V O

Hantkenina singanoae compiled by the pforams@mikrotax project team viewed: 6-2-2023

Taxon Search:

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AphiaID: 1034931 Nomenclatural data on WoRMS
Short stable page link: https://mikrotax.org/pforams/index.php?id=100164 Go to Archive.is to create a permanent copy of this page - citation notes

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test outline:	Stellate	chamber arrangement:	Planispiral	edge view:	Compressed	aperture:	Equatorial
sp chamber shape:	Subtriangular	coiling axis:	N/A	periphery:	Tubulospines	aperture border:	Thick lip
umb chbr shape:	Subtriangular	umbilicus:	Wide	periph margin shape:	Subangular	accessory apertures:	None
spiral sutures:	Moderately depressed	umb depth:	Shallow	wall texture:	Smooth	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Moderately depressed	final-whorl chambers:	4.0-5.0	N.B. These characters are used for advanced search. N/A - not applicable