Clavigerinella caucasica


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

Taxonomy

Citation: Clavigerinella caucasica Subbotina 1958
Rank: Species
Basionym: Hastigerinella caucasica
Synonyms:
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:

Short diagnosis: Final chambers taper into an acute or pointed tip

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: Clavigerinella caucasica differs from other species of Clavigerinella by having adult chambers that taper into an acute or pointed tip (Subbotina, 1958). [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]

Test 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]

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

Character matrix

test outline:Digitatecoiling axis:Very lowchamber arrangement:Pseudoplanispiralumbilicus:Wide
edge view:Hourglassumbilical or test sutures:Moderately depressedspiral sutures:Moderately depressedshell porosity:Finely Perforate: 1-2.5
wall texture:Smoothaperture:Umbilicalaperture border:Thick lipaccessory apertures:Sutural
periphery:N/Aumb chamber shape:Digitatesp chbr shape:Digitateperiph margin shape:Subangular
umb depth:Shallowdiameter mm:0.75width mm:breadth mm:0.2
final-whorl chambers:4.0-4.5

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 very light δ13C and very heavy δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

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]

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 E7 zone (45.72-50.20Ma, top in Lutetian stage). Data source: Eocene Atlas
First occurrence (base): within E7 zone (45.72-50.20Ma, base in Ypresian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Coxall & Pearson 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 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, 1413 pp.

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.; Huber, B.T. & Pearson, P.N., (2003). Origin and morphology of the Eocene planktonic foraminifera Hantkenina. Journal of Foraminiferal Research, 33: 237-261.

Pearson, P.N., (1993). A lineage phylogeny for the Paleogene planktonic foraminifera. Micropaleontology, 39: 193-232.

Pearson, P.N. & others, (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.

Subbotina, N.N., (1958). In: Bykova, N.K., et al., New genera and species of foraminifera. Microfauna of the USSR 1958, Trudy, n.s., , 115(9): 58.


Clavigerinella caucasica compiled by the pforams@mikrotax project team viewed: 23-6-2017

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