CATALOG OF ORIGINAL DESCRIPTIONS: Fleisherites Georgescu 2009

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: pf_cat -> F -> Fleisherites
Other pages this level: Falsella, Falsotruncana, Favusella, Fingeria, Fissoarchaeoglobigerina, Fleisherites,

Fleisherites

Citation: Fleisherites Georgescu 2009
Rank: Genus
Type species: Guembelina glabrans Cushman, 1938.

Current identification/main database link:


Original Description
Diagnosis. Test is nannoperforate to microperforate, smooth or with weak costae and with periapertural pustulose area.

Description. Test is biserial throughout. Earlier chambers are globular, then subrectangular, the last-formed reniform to subcircular. Test is laterally compressed and with subacute periphery as seen in edge view. Aperture is arch-shaped at the base of the last-formed chamber and is bordered by two well-developed, often rimmed, symmetrical anges. Test is smooth or presents weak costae, often on the earlier portion and with well-developed periapertural pustulose area. Test wall is calcitic, hyaline, nannoperforate to microperforate.

Etymology: Genus named in the honor of Dr. Robert L. Fleisher (Micropaleontology Press) for his contributions to the development of the evolutionary classification of the Cenozoic planktic foraminifera.

Extra details from original publication
Species included. Guembelina glabrans Cushman, 1938, p. 15, pl. 3, gs. 1-2.

Remarks. Fleisherites n. gen. is restricted to the Late Cretaceous [uppermost Campanian (?) to Maastrichtian] and includes only taxa with a smooth test wall or, rarely, weak incipient costae and without pore mounds. Periapertural pustulose area is well-developed in all the studied speci- mens. Additional pustulose zones can be developed along the sutures due to imperfect overlapping of the periapertural pustulose areas of the previously formed chambers by the newly added ones (Figure 11). Fleisherites differs from Steineckia and Laeviheterohelix – emended by the absence of the pore mounds on the chamber surface. The origins of Fleisherites are unknown. Incipient costate ornamentation is often observed on the earlier part of the test (Figure 12.6a) and demonstrates that its ancestor is a smooth taxon (Figure 13), but no costate species with a laterally compressed test has been previously described. The incipient costate ornamentation in Fleisherites presents major differences when compared to those in Laeviheterohelix pulchra. Vestigial costae are present only on the last-formed chambers in the latter species and moreover, the test ultrastructure shows that the costae are the ancestral structures of the pore mounds. These further documents that L. pulchra and F. glabrans have different evolutionary origins and belong to different lineages and therefore, should be included in distinct genera.

Stratigraphic range. Upper Campanian (?), Maastrichtian (from the upper part of the Gansserina gansseri Biozone throughout the top of the Pseudoguembelina hariaensis Biozone).

References:

Georgescu, M.D., (2009). Taxonomic revision and evolutionary classification of the biserial Cretaceous planktic foraminiferal genus Laeviheterohelix Nederbragt, 1991. Revista Mexicana de Ciencias Geológicas, 26: 315-334.


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Fleisherites compiled by the pforams@mikrotax project team viewed: 23-11-2017

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