pforams@mikrotax - Jenkinsina columbiana <title>pforams@mikrotax - Jenkinsina columbiana

Jenkinsina columbiana

Classification: pf_cenozoic -> Guembelitrioidea -> Guembelitriidae -> Jenkinsina -> Jenkinsina columbiana
Sister taxa: J. triseriata, J. columbiana, J. sp.


Citation: Jenkinsina columbiana (Howe 1939)
Rank: Species
Basionym: Guembelitria columbiana
Taxonomic discussion:

Several authors (e.g., Kroon and Nederbragt, 1990; Li and Radford, 1992) regard this species and the more elongate form J. triseriata ( =Guembelitria stavensis Bandy) as synonymous. However, Jenkins and others (1998) considered J. columbiana as a distinct form that evolved from J. triseriata, based primarily on observation of the type specimens and previously illustrated hypotypes. We follow the recommendation of Jenkins and others (1998) but note that a more thorough comparative biogeographic and biostratigraphic study of these taxa is warranted. [Huber et al. 2006]

The oldest specimens included in this study, from Zone E2 (Pl.16.1, Figs. 7, 8), have a smoother test than specimens from Zone E4 and higher (e.g., Pl. 16.1, Figs. 10, 11), but none of the observed specimens has pore mounds, as is found in Guembelitria cretacea from the lowermost Paleocene. [Huber et al. 2006]

Catalog entries: Guembelitria columbiana

Type images:

Distinguishing features:
Parent taxon (Jenkinsina):
This taxon: Test small, elongate, subtriangular in outline, with high apical angle (55-62°), periphery rounded and lobulate; chambers inflated and subglobular, triserially arranged, umbilicus moderately deep; aperture a low arch with a thin lip.

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.


Emended description:

Test small, elongate, subtriangular in outline, with high apical angle (55-62°), periphery rounded and lobulate; chambers inflated and subglobular, triserially arranged, about 9 chambers increasing moderately to rapidly in size, umbilicus moderately deep, sutures distinct, curved and depressed; aperture a low arch at the base of the last chamber bordered by a thin imperforate lip. [Premec Fucek et al. 2018]

Wall type:
Microperforate, surface smooth to finely pustulose, irregularly perforated. [Premec Fucek et al. 2018]

Holotype length 0.15 mm, width 0.12 mm. [Premec Fucek et al. 2018]

Character matrix
test outline:Triangularchamber arrangement:Triserialedge view:Equally biconvexaperture:Terminal
sp chamber shape:N/Acoiling axis:Highperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:N/Aumb depth:Deepwall texture:Smoothshell porosity:Microperforate: <1µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:3.0-3.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Similar species

Geographic distribution
Cosmopolitan, abundant in low latitudes in upwelling areas (Spezzaferri, 1994). [Premec Fucek et al. 2018]

Isotope paleobiology
No data available. [Premec Fucek et al. 2018]

Phylogenetic relations
As stated above, the discovery of Jenkinsina columbiana specimens with a microperforate pustulose wall and rare perforated pustules in Oligocene samples from the Adriatic Sea (Pl. 17.5, Figs. 2, 3) and on the shell wall of the the holotype (Pl. 17.5, Fig. 1) and specimens in early Paleocene (Zone P2) samples from Syria (Pl. 17.5, Fig. 10) increases the likelihood that Jenkinsina and Guembelitria are phylogenetically linked. The remaining stratigraphic gap between the highest occurrence in Zone P1a of Guembelitria cretacea and the lowest occurrence in Zone P2 of J. columbiana is probably a consequence of their small size, rare occurrence in open sea environments as well as their high dissolution susceptibility. Examination of exceptionally well-preserved material across this stratigraphic gap is needed to document the evolutionary transition from the ancestral Guembelitria cretacea forms with symmetrical pore mounds and the descendant Jenkinsina columbiana forms with perforated pustules. [Premec Fucek et al. 2018]

Most likely ancestor: benthic ancestor - at confidence level 3 (out of 5). Data source: Premec Fucek et al. 2018.
Likely descendants: Cassigerinelloita amekiensis; Jenkinsina triseriata; plot with descendants

Biostratigraphic distribution

Geological Range:
Notes: Lower Paleocene Zone P2 (this study) to lower Miocene. The oldest specimens are recorded from Zone P2 in the Palmyride region of Syria (this study); the youngest specimens from lower Miocene, Subzone N4b, DSDP Site 116, North Atlantic Ocean (Spezzaferri, 1994).

Beckmann (1957) reported that J. columbiana occurred in the Navet Formation (Trinidad), from the Hantkenina aragonensis to Porticulasphaera mexicana Zone (~E8-E12). Spezzaferri (1994) identified this species in lower Miocene sediments in the North Atlantic Ocean. Jenkins and others (1998) assigned a stratigraphic range for J. columbiana from Zone P9 to Zone P13 (=Zone E7-E12).

Oligocene specimens illustrated in this work have been found at the Eocene/Oligocene boundary in the Palmyride region in Syria (Pl. 17.5, Figs. 4, 5) and in the lower Oligocene (Zone O4) in Adriatic Sea (Pl. 17.5, Figs. 2, 3); specimens from Zone O4 have been found in DSDP Hole 516F in western South Atlantic Ocean (Pl. 17.5, Figs. 6-9).

[Premec Fucek et al. 2018]
Last occurrence (top): within M1 zone (21.12-22.96Ma, top in Aquitanian stage). Data source: Premec Fucek et al. 2018
First occurrence (base): within P2 zone (62.29-62.60Ma, base in Danian stage). Data source: Premec Fucek et al. 2018

Plot of occurrence data:

Primary source for this page: Premec Fucek et al. 2018 - Olig Atlas chap.17 p.474; Huber et al. 2006 - Eocene Atlas, chap. 16, p. 466


Beckmann, J. P. (1957). Chiloguembelina Loeblich and Tappan and related foraminifera from the Lower Tertiay of Trinidad, B.W.I. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli & E. Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin . 215: 83-95. gs V O

Howe, H. V. (1939). Louisiana Cook Mountain Eocene foraminifera. Bulletin of the Geological Survey of Louisiana. 14: 1-122. gs

Huber, B. T., Olsson, R. K. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene microperforate planktonic foraminifera (Jenkinsina, Cassigerinelloita, Chiloguembelina, Streptochilus, Zeauvigerina, Tenuitella, and Cassigerinella) and Problematica (Dipsidripella). 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 16): 461-508. gs V O

Jenkins, D. G. (1978). Guembelitria samwelli Jenkins, a new species from the Oligocene of the Southern Hemishere. Journal of Foraminiferal Research. 8(2): 132-137. gs

Jenkins, D. G., Whittaker, J. E. & Curry, D. (1998). Palaeogene triserial planktonic foraminifera. Journal of Micropalaeontology. 17: 61-70. gs

Kroon, D. & Nederbragt, A. J. (1990). Ecology and paleoecology of triserial planktic foraminifera. Marine Micropaleontology. 16: 25-38. gs

Li, Q. & Radford, S. S. (1992). Morphology and affinity of the planktonic foraminifer Cassigerinelloita amekiensis Stolk and reclassification of Cassigerinelloita Stolk. Proceedings of the Ocean Drilling Program, Scientific Results. 120: 595-602. gs

Premec Fucek, V., Hernitz Kucenjak, M. & Huber, B. T. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Chiloguembelina and Jenkinsina. In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 46(Chap 17): 459-480. gs V O

Spezzaferri, S. (1994). Planktonic foraminiferal biostratigraphy and taxonomy of the Oligocene and lower Miocene in the oceanic record. An overview. Palaeontographia Italica. 81: 1-187. gs


Jenkinsina columbiana compiled by the pforams@mikrotax project team viewed: 29-1-2023

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