Parasubbotina eoclava


Classification: pf_cenozoic -> Globigerinidae -> Parasubbotina -> Parasubbotina eoclava
Sister taxa: P. griffinae, P. eoclava, P. hagni, P. prebetica, P. inaequispira, P. pseudowilsoni, P. variospira, P. varianta, P. pseudobulloides, P. aff. pseudobulloides, P. sp.,

Taxonomy

Citation: Parasubbotina eoclava Coxall, Huber, & Pearson 2003
Rank: Species
Basionym: Parasubbotina eoclava
Synonyms:
Taxonomic discussion: Blow (1979, p. 1198-1199) remarked that the genus Clavigerinella appears in the record “without any transitional forms in terms of apertural characteristics” but nevertheless “some specimens of early forms included in the taxon Subbotina inaequispira (Subbotina)... show some degree of radial elongation of the chambers combined with an aperture which is markedly asymmetrically placed with respect to the umbilicus”, and he suggested that such forms might be ancestral. Toumarkine and Luterbacher (1985, fig. 22.19) illustrated a so-called “G. inaequispiraC. eocanica eocanica transition” which appears to be a sub-adult specimen of C. eocanica. Coxall and others (2003) erected the species Parasubbotina eoclava to include some forms previously included in P. inaequispira that they considered as distinct from the holotype morphology of that taxon and show some transitional features toward Clavigerinella, particularly the strongly asymmetrical aperture with its broad lip, the low trochospiral coiling, and the tendency for radially extended chambers. [Olsson et al. 2006]

Catalog entries: Parasubbotina eoclava

Type images:

Distinguishing features: Test low trochospiral, 4-4½ chambers in final whorl. Chamber size increases rapidly, and the last 1 or 2 chambers are often radially extended. Aperture small, interiomarginal umbilical-extraumbilical with a broad, flaring lip. Wall texture reticulate (Clavigerinella-type),

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


Diagnostic characters: Parasubbotina eoclava is characterized by its low trochospiral coiling, Clavigerinella-type reticulate wall texture, an interiomarginal umbilical-extraumbilical aperture bordered by a broad, flaring apertural lip, and a tendency toward radial extension of the last one or two chambers which anticipates the clavate morphology of Clavigerinella (from which it gets its name). It differs from Parasubbotina inaequispira (Subbotina) in possession of a distinctive flaring lip, more compressed morphology and in the more rapid increase in chamber size through the final whorl. It differs from Clavigerinella eocanica in consistently showing low trochospiral rather than planispiral coiling, having less-pronounced clavate chambers, a more asymmetrical, and lower arched aperture and a less-well developed apertural lip. It is distinguished from Parasubbotina prebetica in having lower trochospiral coiling, a flat spiral side, 4-4½ rather than 4½-5 chambers in the final whorl, chambers increasing gradually in size in the final whorl that are considerable less bulbous than in P. prebetica, a small umbilicus and a more equatorial position and higher arch-morphology of the aperture. [Olsson et al. 2006]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Inflatedcoiling axis:Very lowperiphery:N/Aaperture border:Thick lip
umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Strongly depressedumb depth:Shallowwall texture:Cancellateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:4.0-4.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Parasubbotina eoclava is known from relatively high productivity environments in the low to mid-latitudes, where it often co-occurs with Clavigerinella spp. (Coxall and others, 2003). [Olsson et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes and high productivity/upwelling; based on Olsson et al. (2006c)

Isotope paleobiology: This species was recorded with more positive ∂18O and more negative ∂13C than coexisting Turborotalia frontosa, indicating a cold water sub-thermocline or upwelling environment (Coxall and others, 2003). [Olsson et al. 2006]
Aze et al. 2011 ecogroup 6 - Upwelling/high productivity. Based on occurrence predominantly in sites of high productivity or upwelling. Sources cited by Aze et al. 2011 (appendix S3): Coxall et al. (2003)

Phylogenetic relations: Parasubbotina eoclava evolved from P. inaequispira in the latest early Eocene and was ancestral to Clavigerinella eocaenica (Coxall and others, 2003). [Olsson et al. 2006]

Most likely ancestor: Parasubbotina inaequispira - at confidence level 4 (out of 5). Data source: Olsson et al. 2006 f5.1.
Likely descendants: Clavigerinella eocanica;

Biostratigraphic distribution

Geological Range:
Notes: Zone E7 to E9 (Coxall and others, 2003). [Olsson et al. 2006]
Last occurrence (top): within E9 zone (43.23-43.85Ma, top in Lutetian stage). Data source: Olsson et al. 2006
First occurrence (base): within E7 zone (45.72-50.20Ma, base in Ypresian stage). Data source: Olsson et al. 2006

Plot of occurrence data:

Primary source for this page: Olsson et al. 2006 - Eocene Atlas, chap. 5, p. 99

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

McKeel, D. R. & Lipps, J. J. (1975). Eocene and Oligocene planktonic foraminifera from the Central and Southern Oregon Coast Range. Journal of Foraminiferal Research. 5(4): 249-269. gs

Olsson, R. K., Pearson, P. N. & Huber, B. T. (2006c). Taxonomy, biostratigraphy, and phylogeny of Eocene Catapsydrax, Globorotaloides, Guembelitrioides, Paragloborotalia, Parasubbotina, and Pseudoglobigerinella n. gen. 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 5): 67-110. 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

Petters, V. (1954). Tertiary and Upper Cretaceous foraminifera from Colombia, S. A. Contributions from the Cushman Foundation for Foraminiferal Research. 5(1): 37-41. gs

Toumarkine, M. & Luterbacher, H. (1985). Paleocene and Eocene planktic foraminifera. In, Bolli, H. M. , Saunders, J. B. & Perch-Neilsen, K. (eds) Plankton Stratigraphy. Cambridge Univ. Press, Cambridge 87-154. gs


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Parasubbotina eoclava compiled by the pforams@mikrotax project team viewed: 17-10-2019

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