pforams@mikrotax - Clavigerinella caucasica

pforams@mikrotax - Clavigerinella caucasica pforams@mikrotax - Clavigerinella caucasica

Clavigerinella caucasica

Classification: pf_cenozoic -> Hantkeninidae -> Clavigerinella -> Clavigerinella caucasica
Sister taxa: C. akersi, C. caucasica, C. colombiana, C. eocanica, C. jarvisi, C. sp.

Eocene_Atlas_pl08-2_fig5-8.jpg
Eocene_Atlas_pl08-2_fig4.jpg

Taxonomy

Citation: Clavigerinella caucasica (Subbotina 1958)

taxonomic rank: Species

Basionym: Hastigerinella caucasica

Synonyms:

Hastigerinella caucasica Subbotina, 1958:58, pl. II: figs. 8a-b [middle Eocene, Belaya River, Northern Caucasus, USSR].
“Clavigerinella -Hantkenina transitions”, Coxall and others, 2003:250, pl. 6: figs. 5-8 [Zone P9-P10, topmost lower Eocene to basal middle Eocene, Helvetikum Section, Austria].

Taxonomic discussion: Clavigerinella caucasica has commonly been regarded as a junior synonym of C. eocanica (e.g., Blow, 1979; Pearson, 1993). However, the occurrence of a number of specimens extremely close to the holoype of C. caucasica, which we illustrate in SEM for the first time (Pl.8.2, Figs. 1-3), in the uppermost lower Eocene of the Austrian Helvetikum Section and Tanzania (Tanzanian Drilling Project Site 2; Pearson and others, 2004) indicates that it is a distinctive, recurring morphotype with a restricted range. Moreover, the pointed chambers appear to represent the first stage in the gradual morphological transition to Hantkenina (Coxall and others, 2003). [Coxall & Pearson 2006]

Catalog entries: Hastigerinella caucasica

Type images:

holotype: H. caucasica
holotype: H. caucasica

Distinguishing features:
Parent taxon (Clavigerinella): Final chambers clavate.
This taxon: Final chambers taper into an acute or pointed tip

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

Morphology:

Planispiral or pseudoplanispiral, evolute, biumbilicate or showing a slightly raised spiral side and very shallow umbilicus; 4 - 4½ rapidly enlarging chambers in the final whorl; early chambers rounded, final 1-4 chambers radially elongate, digitate, peripheral outline strongly lobulate; distal chamber ends on final chambers acute, distinctly pointed; equatorial high arched aperture, symmetrical or slightly asymmetrical, bordered by smooth broad imperforate lips; web-like relict apertural lips often present along sutures; sutures shallow, straight, becoming curved in later stages, short compared to overall chamber length. [Coxall & Pearson 2006]

Wall type:

Smooth normal perforate or weakly cancellate; characterized by pores with a wide range of diameters; possibly spinose. [Coxall & Pearson 2006]

Size:

Diameter 0.75 mm; thickness 0.20 mm (Subbotina, 1958). [Coxall & Pearson 2006]

Character matrix
test outline: Stellate chamber arrangement: Pseudoplanispiral edge view: Hourglass aperture: Umbilical
sp chamber shape: Elongate coiling axis: Very low periphery: N/A aperture border: Thick lip
umb chbr shape: Elongate umbilicus: Wide periph margin shape: Subangular accessory apertures: Sutural
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: 4-4.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Known only from the Caucasus Mountains, Austria and Tanzania. [Coxall & Pearson 2006]
Aze et al. 2011 summary: Known only from Austria and Tanzania; based on Coxall & Pearson (2006)

Isotope paleobiology

No data available. [Coxall & Pearson 2006]
Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline; based on comparison with other species of the genus.

Phylogenetic relations

This species probably evolved from C. eocanica in the latest early Eocene by slight tapering of the adult chambers. Hantkenina singanoae n. sp., which bridges the gap between digitate and tubulospinose morphologies, evolved from C. caucasica by further tapering and constriction of the chambers to form a pronounced terminal nub or proto-tubulospine. [Coxall & Pearson 2006]

Most likely ancestor: Clavigerinella eocanica - at confidence level 3 (out of 5). Data source: Coxall & Pearson (2006), fig 8.1.
Likely descendants: Hantkenina singanoae; plot with descendants

Biostratigraphic distribution

Geological Range:
Notes: Subbotina’s holotype is simply listed as being Eocene in age. Our observations in Austria and Tanzania suggest a very restricted range in the uppermost part of early Eocene Zone E7.
[Coxall & Pearson 2006]
Last occurrence (top): within E8 zone (43.85-45.72Ma, top in Lutetian stage). Data source: Coxall & Pearson (2006), fig 8.1
First occurrence (base): within E8 zone (43.85-45.72Ma, base 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: Clavigerinella

Primary source for this page: Coxall & Pearson 2006 - Eocene Atlas, chap. 8, p. 218

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. 2: 1-1413. 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. (1993). A lineage phylogeny for the Paleogene planktonic foraminifera. Micropaleontology. 39: 193-232. 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

Subbotina, N. N. (1958). In: Bykova, N.K., et al., New genera and species of foraminifera. Trudy VNIGRI Mikrofauna USSR. 115(9): 58-61. gs

Clavigerinella caucasica compiled by the pforams@mikrotax project team viewed: 6-10-2024

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test outline:	Stellate	chamber arrangement:	Pseudoplanispiral	edge view:	Hourglass	aperture:	Umbilical
sp chamber shape:	Elongate	coiling axis:	Very low	periphery:	N/A	aperture border:	Thick lip
umb chbr shape:	Elongate	umbilicus:	Wide	periph margin shape:	Subangular	accessory apertures:	Sutural
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:	4-4.5	N.B. These characters are used for advanced search. N/A - not applicable