Dipsidripella liqianyui


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

Taxonomy

Citation: Dipsidripella liqianyui Huber & Pearson 2006
Rank: Species
Basionym: Dipsidripella liqianyui
Synonyms:
Taxonomic discussion: 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:

Short diagnosis: 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.

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: 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]

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]

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: Eocene Atlas
First occurrence (base): within E11 zone (40.40-41.89Ma, base in Lutetian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Huber et al. 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 16, p. 501

References:

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

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. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Cushman Foundation Special Publication. Allen Press, Lawrence, Kansas, pp. 461-508.

Huber, B.T., (1991). Paleogene and early Neogene planktonic foraminifer biostratigraphy of ODP Leg 119 Sites 738 and 744, Kerguelen Plateau (southern Indian Ocean). Proceedings of the Ocean Drilling Program, Scientific Results, 119: 427-449.

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. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Cushman Foundation Special Publication. Allen Press, Lawrence, Kansas, pp. 461-508.

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.


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Dipsidripella liqianyui compiled by the pforams@mikrotax project team viewed: 22-7-2017

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