Dipsidripella


Classification: pf_cenozoic -> Globigerinitidae -> Dipsidripella
Sister taxa: Dipsidripella, Globigerinatella, Globigerinita, Mutabella, Tenuitella,
Daughter taxa: (blue => in age window 0-300Ma)
Like D. danvillensis but with more evolute test, less lobate axial periphery, more flattened spiral side, broader interiomarginal aperture, and without secondary accessory apertures.
Test low trochospire, small, moderately lobate, increasing moderately in size, 4-6 in final whorl; sutures radial and depressed; umbilicus narrow to broad and moderately deep; aperture high arch; a semicircular accessory aperture may occur on the spiral side.
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: This genus was treated in detail in the Atlas of Eocene Planktonic Foraminifera by Huber and others (2006), where two species (D. danvillensis and D. liqianyui) were included. At that time we assigned Dipsidripella to the Problematica because the wall is subtly different from Tenuitella and related forms. Subsequent study (Chapter 15, this volume) suggests that the wall texture differences are not as great as previously thought and the fundamental structure is similar, so we here assign Dipsidripella formally to the Globigerinitidae. (We note in passing that Fleisher, 1974:1033, already suggested that danvillensis had a wall similar to Tenuitella.) We suggest that Dipsidripella was the first of the Globigerinitidae to evolve (in the middle Eocene) giving rise to Tenuitella. Its semi-planktonic shelf sea habitat makes it a plausible intermediate between an as yet unidentified benthic taxon (possibly a species of Praepararotalia; see Liu and others, 1998) and the later, more fully planktonic members of the Globigerinitidae. [Pearson et al. 2018]

 



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:

Distinguishing features: monolamellar wall covered with randomly scattered short, blunt to hispid pustules

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 normal perforate planktonic foraminifera by having a radially crystalline wall covered with randomly scattered short, blunt to hispid pustules; differs from Tenuitella by the greater range of pore sizes and tendency to have dispersed pustules; 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; by the absence of fused or linearly aligned pustules; and by having a rounded rather than subrounded to subcarinate peripheral margin

Wall type: Microperforate to medioperforate, with pore diameters ranging from 0.5-2.0 µm, smooth with surface weakly to densely covered by small, blunt or, more commonly, hispid pustules; radially crystalline internal structure (glutinata-type wall, danvillensis-subtype)

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

Size: Small, mostly <150 µm.

Biogeography and Palaeobiology


Phylogenetic relations: Several authors have suggested that the benthic foram 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: Huber and others (2006) suggested that Dipsidripella danvillensis was restricted to the Eocene whereas D. liqianyui survived into Oligocene Zone O1. Subsequent study has shown that both species persisted well into the early Oligocene [Pearson et al. 2018]
Last occurrence (top): in upper part of Rupelian Stage (62% up, 30.3Ma, 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: Pearson et al. 2018 - Olig Atlas chap.16 p.432 (major update of Huber et al. 2006 - Eocene Atlas chap 16, p. 493)

References:

Fleisher, R.L., (1974). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project, 23: 1001-1072.

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 Allen Press, Lawrence, Kansas, pp. 461-508.

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 Allen Press, Lawrence, Kansas, pp. 461-508.

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.

Pearson, P.N.; Wade, B.S. & Huber, B.T., (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Globigerinitidae (Dipsidripella, Globigerinita, and Tenuitella). In: Wade, B.S. et al. (Editors), Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research Special Pulbication. 46, pp. 429-459.


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Dipsidripella compiled by the pforams@mikrotax project team viewed: 15-12-2018

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