pforams@mikrotax - Morozovella acutispira

Citation: Morozovella acutispira (Bolli&Cita 1960)

Basionym: Globorotalia acutispira

Synonyms:

Globorotalia californica Smith, 1957:190, pl. 28: figs. 22a-23c [homonym]. [Not Globorotalia californica Cushman and Todd,1946.]
Globorotalia acutispira Bolli and Cita, 1960:15, pl. 33:fig.3a-c [Zone P4, Pademo d'Adda, northern Italy].
Globorotalia kolchidica Morozova, 1961:17, pl. 2:fig.2a-c [Zone Msl IV(?) (Cibicides lectus Zone = Zone P3 this paper, upper part), Khokodz' River section, Crimea].
Globorotalia sp. aff. G. kolchidica Morozova.—Luterbacher, 1964:668, text-figs. 6 1 , 62 [Globorotalia pusilla Zone, Gubbio section, central Apennines, Italy].
Globorotalia sp. aff. G. acutispira Bolli and Cita. —Shutskaya, 1970b: 118- 120, pl. 25:fig.7a-c [upper subzone of Acarinina tadjikistanensis djanensis Zone, Olen Platform, boring 210, 517-527 m, Kachan Stage, Tarkhankut Peninsula, Crimea].
Globorotalia (Morozovella) occlusa acutispira (Bolli and Cita).—Belford, 1984:9, pl. 17: figs. 14-21 [upper Paleocene, WABAG Sheet, Papua, New Guinea]. [Olsson et al. 1999]

Taxonomic discussion: This species has been little used in the literature on Paleocene morozovellids. The distinctive character of this form is the raised early part of the test containing the neanic chambers; this feature can vary considerably among individuals in a given sample. Our studies support the diagnosis of Blow (1979) of a biconvex test with a very narrow umbilicus linking it with M. occlusa. If Globorotalia californica Smith, 1957, is indeed a homonym of Globorotalia californica Cushman and Todd, 1946 (according to Blow, 1979), and a senior synonym of Globorotalia acutispira Bolli and Cita, 1960, it should be renamed, although we can agree (provisonally) with Blow that this may be unnecessary.
A closely related, if not identical, morphospecies is M. kolchidica ( Morozova). Morozova (1961) referred to theflator weakly convex central part of the spiral side of the test, which we have confirmed by examinaton of the holotype (3510/12 in the micropaleontological collections of GAN, Moscow). Comparison with the refigured holotype of M. acutispira Bolli and Cita (in Luterbacher, 1964, text-fig. 72a-c) reveals two virtually identical forms. Blow's (1979) interpretation of M. kolchidica as a junior synonym of G. (M.) formosa gracilis Bolli is considered anomalous and incorrect (although the two forms are clearly homeomorphic in the same manner as are M. velascoensis and M. caucasica). Morozovella kolchidica was described from (and is characteristic of) Zone P3 (as well as Zone P4); M. gracilis was described from (and is characteristic of) Zone P6 (as well as Zone P7). Morozovella acutispira is also homeomorphic with M. marginodentata (Subbotina), but the latter bears a consistently more massive muricocarina and lacks the apiculate early portion of the test (see also Berggren,
1977).
Illustrated on Plate 11: Figures 13-15 is a specimen from the collections of Shutskaya (no. 645) in VNIGRI (St. Petersburg), which is probably referable to M. acutispira. Although the slide containing this specimen is labeled as Globorotalia angulata var. kubanensis Shutskaya, the illustration of the holotype resembles M. conicotruncata (Subbotina); however, because the holotype in Moscow is lost, the identity of this taxon cannot be determined. Further confusing the taxonomic status of Shutskaya's taxon is the other specimen from the same slide (no. 645) illustrated on Plate 11: Figures 10-12. This specimen is probably referable to M. apanthesma. [Olsson et al. 1999]

Distinguishing features:
Parent taxon (Morozovella): Test typically plano-convex, chambers strongly anguloconical.
Wall strongly pustulose (muricate) on parts of spire and umbilicus. Most species with muricocarina.
This taxon: Like M. pasionensis but with development of a biconvex test; fewer chambers in the final whorl (4-6); and smaller umbilicus. Early part of test raised on spiral side.

Description

Biogeography and Palaeobiology

The geographic distribution of this morphospecies appears characteristic of subtropical to tropical regions as does that of occlusa. [Olsson et al. 1999]
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson et al. (1999)

The δ13C of Morozovella acutispira is similar to that of coexisting morozovellids but is more positive than that of Subbotina and Globanomalina. The δ18O ofM acutispira is lighter than that of Globanomalina and Subbotina (Berggren and Norris, 1997). [Olsson et al. 1999]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy _¹³C and relatively light _¹⁸O. Sources cited by Aze et al. 2011 (appendix S3): Berggren & Norris (1997)

This morphospecies is closely related to, and probably evolved from, M. pasionensis by an increase in spire height, development of a biconvex test, a decrease in the number of chambers in the final whorl, and a decrease in the size of the umbilicus. Morozovella acutispira is closely related to M. occlusa as herein described. [Olsson et al. 1999]

Most likely ancestor: Morozovella pasionensis - at confidence level 4 (out of 5). Data source: Olsson et al. (1999) f5a.

Biostratigraphic distribution

Geological Range:
Notes: Near the Zone P3/P4 boundary to the top of Zone P4b. [Olsson et al. 1999]
Last occurrence (top): at top of P4b subzone (100% up, 57.8Ma, in Thanetian stage). Data source: Olsson et al. (1999) f5a
First occurrence (base): at top of P3b subzone (95% up, 60.8Ma, in Selandian stage). Data source: Olsson et al. (1999) f5a

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 56

References:

Belford, D. J. (1984). Tertiary foraminifera and age of sediments, Ok Tedi-Wabag, Papua New Guinea. Australia Bureau of Mineral Resources Geology and Geophysics, Bulletin. 216: 1-52. gs

Bolli, H. M. & Cita, M. B. (1960). Globigerine e Globorotalie del Paleocene di Paderno d'Adda (Italia). Rivista Italiana di Paleontologia e Stratigrafia. LXVI(3): 1-42. gs

Cushman, J. A. & Todd, R. (1946). A Foraminiferal Fauna from the Paleocene of Arkansas. Contributions from the Cushman Laboratory for Foraminiferal Research. 22(2): 45-65. gs

Luterbacher, H. P. (1964). Studies in some Globorotalia from the Paleocene and Lower Eocene of the Central Apennines. Eclogae Geologicae Helvetiae. 57: 631-730. gs O

Morozova, V. G. (1961). Datsko-Montskie planktonnye foraminifery yuga SSSR [Danian-Montian Planktonic Foraminifera of the Southern USSR]. Paleontologicheskiy Zhurnal. (2): 8-19. gs O

Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. (85): 1-252. gs

Shutskaya, E. K. (1970b). Stratigrafiya, foraminifery i paleogeografiya nizhnego paleogena Kryma, predkavkaz'ya i zapadnoi chadsti srednei azii [Stratigraphy, Foraminifera and Paleogeography of the Lower Paleogene in the Crimea, Precaucasus and the Western Part of Central Asia]. Trudy Vsesoyuznego Neftyanogo Nauchno-Issledovatel'skogo Geologo-Razvedochnogo Instituta (VNIGRI). 70(1): 256-. gs

Smith, B. Y. (1957). Lower Tertiary foraminifera from Contra Costa county, California. University of California Publications in Geological Sciences. 32(3): 127-242. gs

Soldan, D. M., Petrizzo, M. R. & Silva, I. P. (2014). Pearsonites, a new Paleogene planktonic foraminiferal genus for the broedermanni lineage. Journal of Foraminiferal Research. 44: 17-27. gs

test outline:	Circular	chamber arrangement:	Trochospiral	edge view:	Equally biconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Petaloid	coiling axis:	High	periphery:	Muricocarinate	aperture border:	N/A
umb chbr shape:	Subtriangular	umbilicus:	Narrow	periph margin shape:	Subangular	accessory apertures:	None
spiral sutures:	Raised muricate	umb depth:	Deep	wall texture:	Moderately muricate	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Moderately depressed	final-whorl chambers:	4-6	N.B. These characters are used for advanced search. N/A - not applicable

Morozovella acutispira

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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