Dipsidripella liqianyui


Classification: pf_cenozoic -> Globigerinitidae -> Dipsidripella -> Dipsidripella liqianyui
Sister taxa: D. liqianyui, D. danvillensis, D. sp.,

Taxonomy

Citation: Dipsidripella liqianyui Huber & Pearson, in Huber et al. 2006
Rank: Species
Basionym: Dipsidripella liqianyui
Synonyms:
Taxonomic discussion: This species was described in the Atlas of Eocene Planktonic Foraminifera (Huber and others, 2006). Here we include Globorotalia denseconnexa Subbotina, 1960, in questionable synonymy (see Chapter 20, this volume). See under D. danvillensis for how to distinguish the two species. The highest known occurrence is in ODP Hole 738B where the range is truncated by a hiatus in Zone AP13 (lower Oligocene) in a sample that also contains Pseudohastigerina micra and is therefore equivalent to (sub)tropical Zone O1, probably the upper part (see Huber, 1991, Table 1). The precise extinction level has yet to be confirmed, and it is not known whether it preceded, followed, or was simultaneous with the extinction of D. danvillensis. [Pearson et al. 2018]

This new species is placed in Dipsidripella because of its finely perforate test, smooth, pustulose to hispid surface texture, and highly arched interiomarginal aperture. Because of its small size and thin shell wall this taxon is easily overlooked in microfossil assemblages and is prone to dissolution and recrystallization. As a result, its stratigraphic and geographic distribution have been incompletely documented and its taxonomic status cannot be firmly resolved until better preserved specimens are studied. Specimens that were described as Planorotalites sp. 1 and Praetenuitella sp. 2 by Huber (1991) from middle and upper Eocene chalk sediments at ODP Site 738 (Kerguelen Plateau) are now placed in D. liqianyui as they differ only in degree of evoluteness in coiling and axial compression of the test. [Huber et al. 2006]

Catalog entries: Dipsidripella liqianyui

Type images:

Distinguishing features: Like D. danvillensis but with more evolute test, less lobate axial periphery, more flattened spiral side, broader interiomarginal aperture, and without secondary accessory apertures.

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: Differs from species included in Tenuitella by having a larger pore size, its more evolute test with a less lobate equatorial periphery, lower trochospire, more flattened spiral side, shallower, broader umbilicus, and presence of pustules in the umbilicus. Differs from Dipsidripella danvillensis by its more evolute test, less lobate axial periphery, more flattened spiral side, broader interiomarginal aperture, and absence of secondary accessory apertures. [Huber et al. 2006]

Wall type: Finely perforate, surface hispid to moderately pustulose, pustules scattered on umbilical and spiral surfaces of test. [Huber et al. 2006]

Test morphology: Test very small, equally biconvex to planoconvex, weakly lobate, circular to subcircular in equatorial outline, axial periphery rounded to slightly compressed; 5-7 subglobular chambers in the final whorl, sometimes becoming slightly reniform in the final whorl, coiled in a low trochospire, increasing gradually in size; sutures weakly depressed, radial to slightly curved on the spiral side, radial on umbilical side; umbilicus broad and shallow, often ornamented with a random scattering of pustules; aperture a subcircular extraumbilical-umbilical arch that is bordered by a narrow to moderately broad, equidimensional lip. [Huber et al. 2006]

Size: Holotype (USNM 523431) maximum diameter 0.10 mm, breadth 0.04 mm; Paratype (USNM 523432) maximum diameter 0.09•€Êmm, breadth 0.04 mm. [Huber et al. 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Petaloidcoiling axis:Lowperiphery:N/Aaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Wideperiph margin shape:Moderately roundedaccessory apertures:None
spiral sutures:Weakly depressedumb depth:Shallowwall texture:Moderately pustuloseshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:5.0-7.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Identified only in the southern Indian Ocean at ODP Site 738 (Kerguelen Plateau) and Site 761 (Wombat Plateau). [Huber et al. 2006]

Isotope paleobiology: No data available. [Huber et al. 2006]

Phylogenetic relations: May have evolved from D. danvillensis during the middle Eocene. [Huber et al. 2006]

Most likely ancestor: Dipsidripella danvillensis - at confidence level 2 (out of 5). Data source: Huber et al. 2006.

Biostratigraphic distribution

Geological Range:
Notes: Middle Eocene Zone E11 through lower Oligocene Zone O1. [Huber et al. 2006]
Last occurrence (top): within O1 zone (32.10-33.90Ma, top in Rupelian stage). Data source: Huber et al. 2006
First occurrence (base): within E11 zone (40.40-41.89Ma, base in Lutetian stage). Data source: Huber et al. 2006

Plot of occurrence data:

Primary source for this page: Pearson et al. 2018 - Olig Atlas chap.16 p.434; Huber et al. 2006 - Eocene Atlas, chap. 16, p. 501

References:

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

Huber, B. T. (1991c). Paleogene and Early Neogene Planktonic Foraminifer Biostratigraphy of Sites 738 and 744, Kerguelen Plateau (Southern Indian Ocean). Proceedings of the Ocean Drilling Program, Scientific Results. 119: 427-449. 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

Pearson, P. N., Wade, B. S. & Huber, B. T. (2018c). Taxonomy, biostratigraphy, and phylogeny of Oligocene Globigerinitidae (Dipsidripella, Globigerinita, and Tenuitella). 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 16): 429-458. gs

Stott, L. D. & Kennett, J. P. (1990). The Paleoceanographic and Paleoclimatic signature of the Cretaceous/Paleogene boundary in the Antarctic: Stable isotopic results from ODP Leg 113. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 829-848. gs

Subbotina, N. N., Pishvanova, L. S. & Ivanova, L. V. (1960). Stratigrafiya oligotsenovykh i miotsenovykh otlozheniy predkarpat'ya po foraminiferam. In, Subbotina, N. N. (ed.) Mikrofauna of the USSR XI. Trudy Vsesoyuznogo neftyanogo nauchno-issledovatel'skogo geologo-razvedochnogo instituta, New Series. 153: 5-155. gs


logo

Dipsidripella liqianyui compiled by the pforams@mikrotax project team viewed: 17-10-2019

Taxon Search:
Advanced Search

Short stable page link: http://mikrotax.org/pforams/index.php?id=100087 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics