Dipsidripella


Classification: pf_cenozoic -> microperforate -> Problematica -> Dipsidripella
Sister taxa: Dipsidripella, P. sp.,
Daughter taxa (blue => in age window 0-300Ma)
This species differs from Praepararotalia inconspicua (Howe) by having a rounded rather than subangular or carinate peripheral margin, a gently convex rather than flattened spiral side, and an interiomarginal rather than areal position of the aperture; differs from D.? liqianyui n. sp. by its more lobate and broadly rounded equatorial periphery, less flattening of the spiral side, and absence of pustules in the umbilicus; differs from Praepararotalia perclara Loeblich and Tappan by the presence of pustulose ornamentation on both sides, rather than only on umbilical side of the test (e.g., see Liu and others, 1998, pl. 1, figs. 1-9, text-fig. 4-2); differs from A. medizzai by its monolamellar wall, hispid, rather than coarsely muricate wall texture, and distinctive, often highly arched aperture.
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.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Dipsidripella Brotea, 1995, emended this study
Rank: Genus
Type species: Dipsidripella hodisensis Brotea, 1995
Taxonomic discussion: Jenkins (1971) erected the monotypic subgenus Globorotalia (Testacarinata) to accommodate the small, planoconvex, carinate species Globorotalia inconspicua Howe, and he regarded his subspecies Globorotalia (Turborotalia) inconspicua aculeata as the non-carinate, hispid ancestor of G. (T.) inconspicua. Liu and others (1998) transferred inconspicua and aculeata to the new benthic genus Praepararotalia because of gross similarities in their “globigerinid” morphology and similar biofacies distributions that indicated a benthic mode of life. However, significant differences in wall texture, roundness of the equatorial periphery and apertural morphology between aculeata (which is now considered a junior synonym of danvillensis Howe) and the other species that Liu and others (1998) included in Praepararotalia, warrant their separation at the genus level. The most appropriate genus available for danvillensis is Dipsidripella, which was defined by Brotea (1995) to accommodate her new species D. hodisensis Brotea. This latter species was described from uppermost Eocene-lowermost Oligocene sediments in northern Transylvania, but it too is here considered a junior synonym of danvillensis (see discussion below).
Abundance of D. danvillensis in shallow to marginal marine biofacies, its near absence from pelagic carbonate deposits, its monolamellar wall structure, and its more positive oxygen and much more negative carbon isotope values relative to co-occurring planktonic species (Fig. 16.3) suggest it may have lived in a benthic or merobenthic habitat. However, the overall test morphology (e.g., presence of globular chambers, an interiomarginal aperture, and evenly scattered, smooth to pustulose test surface ornamentation) is typical of planktonic foraminifera. Because of the uncertainty regarding its mode of life and phylogenetic origin, Dipsidripella is placed in the Problematica category.
[Huber et al. 2006]

Catalog entries: Dipsidripella;

Type images:

Short diagnosis: Differs from normal perforate planktonic foraminifera by having a monolamellar wall surface covered with randomly scattered short, blunt to hispid pustules; differs from Tenuitella by the greater range of pore sizes and tendency to have a hispid wall texture; differs from Praepararotalia Liu and others (1998) by the more even distribution of pustules on both sides of the test rather than restriction of pustules to the umbilical side, absence of fused or linearly aligned pustules, and by having a rounded rather than subrounded to subcarinate peripheral margin; differs from Acarinina by presence of a monolamellar wall and less dense and less coarsely pustulose surface ornamentation.

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 normal perforate planktonic foraminifera by having a monolamellar wall surface covered with randomly scattered short, blunt to hispid pustules; differs from Tenuitella by the greater range of pore sizes and tendency to have a hispid wall texture; differs from Praepararotalia Liu and others (1998) by the more even distribution of pustules on both sides of the test rather than restriction of pustules to the umbilical side, absence of fused or linearly aligned pustules, and by having a rounded rather than subrounded to subcarinate peripheral margin; differs from Acarinina by presence of a monolamellar wall (Pl. 16.8, Fig. 9) and less dense and less coarsely pustulose surface ornamentation.
[Huber et al. 2006]

Wall type: Calcareous, monolamellar, microperforate to finely perforate with pore diameters ranging from 0.5 to 2.0 µm; surface weakly to densely covered by small, blunt or, more commonly, hispid pustules; [Huber et al. 2006]

Test morphology: Test small-to medium-sized, peripheral margin rounded, peripheral outline subquadrate to subcircular, moderately lobate; chambers globular, inflated, trochospiral, arranged in a low to slightly high spire; sutures strongly depressed, radial on both sides; aperture interiomarginal, umbilical-extraumbilical, variable from a low and broad to narrow and high arch; small semicircular secondary apertures may occur at the intersection of the spiral and chamber sutures.
[Huber et al. 2006]

Biogeography and Palaeobiology


Phylogenetic relations: Several authors have suggested that Praepararotalia inconspicua (Jenkins) is the most likely ancestor of D. danvillensis (e.g., Jenkins, 1966, 1971; Liu and others, 1998). On the other hand, observation of a monolamellar wall in Tenuitella (e.g., Pl. 16.6, Fig. 9), similarity between the test morphology of tenuitellids and D. danvillensis, and determination that D. danvillensis and T. insolita have similar oxygen and carbon isotope values (Fig. 16.3) suggests a possible phylogenetic link between Dipsidripella and Tenuitella. This relationship is considered tentative because of the pustulose wall and somewhat larger pore size (in contrast to typical microperforate wall) in Dipsidripella.
[Huber et al. 2006]

Biostratigraphic distribution

Geological Range:
Notes: Middle Eocene- lowermost Oligocene (~Zones E9-O1).
[Huber et al. 2006]
Last occurrence (top): in lower part of Rupelian Stage (31% up, 32.1Ma, in Rupelian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Lutetian Stage (60% up, 43.8Ma, in Lutetian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Huber et al. 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 16, p. 493

References:

Brotea, D., (1995). A new planktonic foraminifer in upper Eocene deposits from north Transylvania. Romanian Journal of Paleontology, 76: 31-33.

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.

Jenkins, D.G., (1966). Two lineages from the Neogene planktonic foraminifera of the Australasian region. In: Drooger, C.W. et al. (Editors), Proceedings of the Third Session in Berne, International Union of Geological Sciences, Committee on Mediterranean Neogene Stratigraphy. E. J. Brill, Switzerland, pp. 23-29.

Jenkins, D.G., (1966). Planktonic foraminiferal zones and new taxa from the Danian to lower Miocene of New Zealand. New Zealand Journal of Geology and Geophysics, 8: 1088-1126.

Jenkins, D.G., (1971). New Zealand Cenozoic Planktonic Foraminifera. New Zealand Geological Survey, Paleontological Bulletin, 42: 1-278.

Liu, C.; Olsson, R.K. & Huber, B.T., (1998). A benthic paleohabitat for Praepararotalia gen. nov. and Antarcticella Loeblich and Tappan. Journal of Foraminiferal Research, 28: 75-90.


logo

Dipsidripella compiled by the pforams@mikrotax project team viewed: 19-11-2017

Taxon Search:
Advanced Search

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