Astrorotalia palmerae


Classification: pf_cenozoic -> muricate non-spinose -> Truncorotaloididae -> Astrorotalia -> Astrorotalia palmerae
Sister taxa: A. palmerae,

Taxonomy

Citation: Astrorotalia palmerae (Cushman & Bermudez 1937)
Rank: Species
Basionym: Globorotalia palmerae
Synonyms:
Taxonomic discussion: The planktonic habit of this taxon has been questioned/debated by several authors (Berggren, 1968, p. 313; 1968:5-6; Stainforth and others, 1975, p. 212) and rejected outright by others (Blow, 1979, p. 280). However, Blow, writing in the late 1960s and early 1970s did not have the benefit of the insight/observations of Schmidt and Raju (1973), which appeared a year after his death. Schmidt and Raju (1973) and, later, Hillebrandt (1976, pl. 7, fig. 4) have convincingly demonstrated with SEM illustrations that this taxon is not referable to the shallow water taxon Pararotalia (characterized by having a prominent umbilical plug and areal aperture), and hence palmerae has been considered a planktonic taxon since that time (see further discussion of the taxonomy and suggested phylogeny of the pseudoscitula-palmerae plexus under P. pseudoscitula). Specimens intermediate/transitional between pseudoscitula and palmerae have been illustrated by Schmidt and Raju (1973, pl. 1); Poore and Bybell (1988, pl. 1: figs. 1,2), Blow (1979, pl. 264), and on Plate 12.1 of this Atlas. This taxon appears to have a decidedly restricted geographic (and stratigraphic) distribution having been recorded (to date) only from equatorial, fully tropical areas.
Astrorotalia stellaria Turnovsky is considered a junior synonym of Globorotalia palmerae Cushman and Bermúdez. However, Turnovsky’s genus name Astrorotalia is recognized here to denote the unique development/extension of radially elongate chamber margins into keel-spines. [Berggren et al. 2006]

Catalog entries: Globorotalia (Astrorotalia) stellaria;
Globorotalia palmerae;

Type images:

Short diagnosis: This form is uniquely distinguished by the peripheral keel extending into blade-like keel-spines on each chamber.

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: This form is uniquely distinguished by the peripheral keel extending into blade-like keel-spines on each chamber. [Berggren et al. 2006]

Wall type: Normal (coarsely) perforate, weakly muricate, nonspinose. [Berggren et al. 2006]

Test morphology: Low trochospiral test with peripheral keel extending into blade-like, tapering keelspines on each chamber, oval to subcircular periphery, stellate shape; in umbilical view 5-6, moderately inflated, triangular-shaped chambers in last whorl, increasing slowly in size; sutures depressed, radial, umbilicus narrow, shallow, aperture a low umbilical-extraumbilical slit bordered by a thick lip extending to the periphery; in spiral view about 10-12 triangular shaped chambers in 2-2½ whorls, sutures distinct, curved, depressed and bearing extension of peripheral; in edge view umbilical and spiral sides planoconvex (slight inflation of chambers yields a lobulate outline in edge view), periphery with blade-like extensions of a peripheral keel. [Berggren et al. 2006]

Size: Length with keel-spines: 0.4-0.6 mm; without spines: 0.28-0.35 mm; breadth with keel-spines: 0.36 -0.46 mm; without keel-spines: 0.24-0.3 mm; thickness: 0.10-0.12 mm (Cushman and Bermudez, 1937, p. 26). [Berggren et al. 2006]

Character matrix

test outline:Stellatecoiling axis:Lowchamber arrangement:Trochospiralumbilicus:Wide
edge view:Planoconvexumbilical or test sutures:Moderately depressedspiral sutures:Moderately depressedshell porosity:Macroperforate: >2.5
wall texture:Finely muricateaperture:Umb.-extraumbilicalaperture border:Thick lipaccessory apertures:None
periphery:Single keelumb chamber shape:Subtriangularsp chbr shape:Subtriangularperiph margin shape:Subangular
umb depth:Shallowdiameter mm:0.36-0.46width mm:breadth mm:0.10-0.12
final-whorl chambers:5.0-6.0

Biogeography and Palaeobiology


Geographic distribution: Restricted to tropical regions (Caribbean, Tethys (Spain, Middle East [Israel, Turkey], India). [Berggren et al. 2006]
Aze et al. 2011 summary: Low latitudes; based on Berggren et al. (2006a)

Isotope paleobiology: No data available. [Berggren et al. 2006]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy δ13C and relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Phylogenetic relations: This form evolved from Planorotalites pseudoscitula by extension of the chambers and development of a peripheral keel which extends as a blade-like keel-spine on each chamber. Apparently it left no descendants. [Berggren et al. 2006]

Biostratigraphic distribution

Geological Range:
Notes: Restricted to within Zone E7. [Berggren & Pearson 2006]
Last occurrence (top): within E7 zone (45.72-50.20Ma, top in Lutetian stage). Data source: Eocene Atlas
First occurrence (base): within E7 zone (45.72-50.20Ma, base in Ypresian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Berggren et al. 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 12, p. 379

References:

Berggren, W.A., (1968). Phylogenetic and taxonomic problems of some Tertiary planktonic foraminiferal lineages. Tulane Studies in Geology and Paleontology, 6(1): 1-22.

Berggren, W.A., (1977). Atlas of Palaeogene Planktonic Foraminifera: some Species of the Genera Subbotina, Planorotalites, Morozovella, Acarinina and Truncorotaloides. In: Ramsay, A.T.S. (Editor), Oceanic Micropaleontology. Academic Press, London, pp. 205-300.

Berggren, W.A.; Olsson, R.K. & Premoli Silva, I., (2006). Taxonomy, biostratigraphy and phylogenetic affinities of Eocene Astrorotalia, Igorina, Planorotalites, and Problematica (Praemurica? lozanoi). In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. 41. Allen Press, Lawrence, Kansas, pp. 377-400.

Bermudez, P.J., (1937). Nuevas especies de Foraminiferos del Eoceno de las cercanias de Guanajay, provincia Pinar del Rio, Cuba. Memorias de la Sociedad Cubana de Historia Natural, 11(4): 237-248.

Bermudez, P.J., (1949). Tertiary smaller foraminifera of the Dominican Republic. Contributions from the Cushman Laboratory for Foraminiferal Research special publication, 25: 1-322.

Bermudez, P.J., (1961). Contribucion al estudio de las Globigerinidea de la region Caribe-Antillana (Paleoceno-Reciente). Mem. III Congreso Geol. Venez. Editorial Sucre, Caracas, 1119-1393 pp.

Blow, W.H., (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden, 1413 pp.

Bolli, H.M., (1957). Planktonic foraminifera from the Eocene Navet and San Fernando formations of Trinidad. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera: U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, D.C., pp. 155-172.

Cushman, J.A. & Bermudez, P.J., (1937). Futher new species of foraminifera from the Eocene of Cuba. Contributions From the Cushman Foundation for Foraminiferal Reseach, 13(1): 1-29.

Gallego 1973 [sorry, not in our bibliography yet]

Hillebrandt, A., (1976). Los foraminiferos planctonicos, nummulitidos y coccolitoforidos de la zona de Globorotalia palmerae del Cuisiense (Eoceno inferior) en el SE de Espana, (Provincias de Murcia y Alicante. Revista Española de Micropaleontología, 8(3): 323-394.

Poore, R.Z. & Bybell, L.M., (1988). Eocene to Miocene biostratigraphy of New Jersey Core ACGS #4: Implications for regional stratigraphy. U.S. Geological Survey Bulletin 1829: 1-41.

Schmidt & Raju 1973 [sorry, not in our bibliography yet]

Stainforth, R.M.; Lamb, J.L.; Luterbacher, H.; Beard, J.H. & Jeffords, R.M., (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. The University of Kansas Paleontological Contributions, 62: 1-425.

Toumarkine, M. & Luterbacher, H. (Editors), (1985). Paleocene and Eocene planktic foraminifera. Plankton Stratigraphy. Cambridge Univ. Press, Cambridge, 87-154 pp.

Turnovsky, K., (1958). Eine neue Art von Globorotalia Cushman aus dem Eozaen Anatoliens und ihre Zuordnung su einer neuen Untergattung. Bulletin of the Geological Society of Turkey, 6(2): 80-86.


Astrorotalia palmerae compiled by the pforams@mikrotax project team viewed: 26-6-2017

Taxon Search:
Advanced Search




Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics