Planorotalites


Classification: pf_cenozoic -> Truncorotaloididae -> Planorotalites
Sister taxa: Acarinina, Praemurica, Igorina, Planorotalites, Astrorotalia, Morozovella, Morozovelloides,
Daughter taxa: (blue => in age window 0-300Ma)
Like P. pseudoscitula but stronger pustulation and muricae, higher rate of increase in chambers, more distinct and flush to slightly raised sutures on spiral side, test flatter and more equally biconvex.
Test small, weakly biconvex and muricate, distinctly carinate
Specimens which cannot be assigned to established species

Taxonomy

Citation: Planorotalites Morozova, 1957
Rank: Genus
Type species: Globorotalia pseudoscitula Glaessner, 1937
Taxonomic discussion: The Paleogene genera Planorotalia (type species: Planulina membranacea Ehrenberg 1854) and Planorotalites (type species: Globorotalia pseudoscitula Glaessner 1937) were erected by Morozova (1957) for low-trochospiral, normal (finely) perforate, smooth-walled forms whose sole distinction was the presence of a keel in the latter. McGowran (1968) recognized the essential synonymy of these two genera and in his lineage 6 suggested an evolutionary sequence leading from Planorotalites compressa to P. pseudoscitula. The genus Globanomalina was retained for smooth-walled planispiral forms that evolved from either chapmani-pseudomenardii plexus or G. imitata, in the mistaken belief that the type species of Globanomalina is planispiral (cf. Banner, 1989, p. 171-173). In his contemporaneous publication, Berggren (1968) placed these forms in his ‘lineage 2’ (G. pseudobulloides-G. pseudoscitula lineage). (Earlier discussion of this lineage may be found in papers by Bolli, 1957; Berggren, 1962 and Hillebrandt, 1964.)
With the demonstration that the type species of Globanomalina (G. ovalis Haque) is slightly trochoid rather than planispiral (Berggren, 1968; Banner, 1989), that ovalis is closely allied with imitata and the eventual evolution of the planispiral genus Pseudohastigerina near the Paleocene/Eocene boundary from the ovalis -luxorensis group (and not chapmani; Olsson and others, 1999), and that chapmani is part of a separate globanomalinid lineage characterized by low-trochospiral, compressed tests (Olsson and others, 1999), phylogenetic relationships within this group would appear to have been more satisfactorily clarified than heretofore.
Banner (1989, p. 177) drew attention to the fact that the smooth-walled and “microperforate” (actually all forms are normal perforate; see also Olsson and others, 1999) forms of the genus Globanomalina should be “distinguished from the macroperforate (and more distinctly muricate) genus Planorotalites Morozova (e.g., its type species, P. pseudoscitula (Glaessner), Zones P10-13)...” Accordingly we restrict the concept of Planorotalites to the generally small (<0.3mm) normal perforate, muricate forms typified by P. pseudoscitula. As such the genus has its origin in the late Paleocene (Biochron P5) and ranges through the middle Eocene; it probably evolved from a juvenile morozovellid (? M. occlusa) by neoteny. [Berggren et al. 2006]

Catalog entries: Planorotalites;

Type images:

Distinguishing features: Biconvex, keeled test with densely perforate surface

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

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): in mid part of Priabonian Stage (48% up, 35.9Ma, in Priabonian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Thanetian Stage (65% up, 57.1Ma, in Thanetian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Berggren et al. 2006 - Eocene Atlas, chap. 12, p. 390

References:

Banner, F.T., (1989). The nature of Globanomalina Haque, 1956. Journal of Foraminiferal Research, 19: 171-179.

Berggren, W.A., (1962). Stratigraphic and taxonomic-phylogenetic studies of Upper Cretaceous and Paleogene planktonic foraminifera. Stockholm Contributions in Geology, 9(2): 107-129.

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.; 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 Allen Press, Lawrence, Kansas, pp. 377-400.

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.

Ehrenberg, C.G., (1854). MikrogeologieL. Voss, Leipzig, 1-374 pp.

Glaessner, M.F., (1937). Studien über foraminiferen aus der kreide und dem Tertiär des Kaukasus. I. Die foraminiferen der ältesten Tertiärschichten des Nordwest-Kaukasus. Problemy Paleontologii, Paleontologicheskay Laboratoriya Moskovskogo Gosudarstvennogo Universiteta, 2-3: 349-410.

Glaessner, M.F., (1937). Planktonforaminiferen aus der Kreide und dem Eozän und ihre stratigraphische Bedeutung. Etyudy po Mikropaleontologiy, Paleontologicheskaya Laboratoriya Moskovskogo Gosudarstvennogo Universiteta. [Studies in Micropaleontology, Publications of the Laboratory of Paleontology, Moscow University], 1(1): 27-46.

McGowran, B., (1968). Reclassification of Early Tertiary Globorotalia. Micropaleontology, 14: 179-198.

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


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

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