Catalog - Ehrenbergites

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Ehrenbergites

Citation: Ehrenbergites Georgescu 2013

Type age (chronostrat): Santonian–Maastrichtian

Type locality: Geographic distribution: Cosmopolitan.

Species included: IS: E. striata (Ehrenberg 1838) (Plate 3, Figures 9–11, Plate 4, Figures 1–8) and FDS: E. riograndensis (Martin

1972) (Plate 4, Figures 9–11).

Diagnosis: Santonian–Maastrichtian directional lineage consisting of globular–chambered tests ornamented with longitudinal leptocostae and the apertures bordered by orthoflanges; multichamber growth occurs in the adult stage of the FDS.

Description: Test with the chambers alternately added with respect to the test growth axis in the IS and multichamber growth in the adult stage in the FDS. Chambers are globular throughout; the adult stage of the FDS consists of up to four chamber sets. Sutures are distinct and depressed, straight to slightly curved throughout. Test is symmetrical in edge view, with broadly rounded and simple periphery. In the IS the aperture is in the shape of a medium high arch situated at the base of the last–formed chamber; it is bordered by two symmetrically developed subtriangular orthoflanges, one on each test side; the aperture in the adult stage of the FDS is multiple. Chamber surface is ornamented with longitudinal leptocostae (0.0014–0.0027 mm in width in the IS and 0.0027–0.0044 mm in the FDS); a periapertural pustulose area consisting of dome–like and irregular pustules occurs in the chamber anterior portion.Test wall is calcitic, hyaline, simple and perforate; pores are circular, with a diameter of 0.0004–0.0009 mm in the IS and 0.0006–0.0012 mm in the FDS.

Directional lineage named after Dr C.G. Ehrenberg.

Comments on nomenclature: The Late Cretaceous globular–chambered heterohelicid tests were included by Ehrenberg (1838) in the genus Textularia, but in the subsequent works he replaced it with Textilaria. Egger (1899) described the genus Gümbelina (type species Textularia globulosa Ehrenberg 1838) to accommodate these heterohelicid tests; Gümbelina was widely accepted by researchers until Loeblich and Tappan (1961a) demonstrated that the name Gümbelina was previously used for a Carboniferous siliceous microfossil and therefore is invalid according to the ICZN rules. A new taxonomic solution was adopted by Loeblich (1951) and Montanaro Gallitelli (1957) who considered Heterohelix valid and it was widely adopted and included in the taxonomic revisions by Brown (1969), Masters (1977), Weiss (1983) and Nederbragt (1991); herein it is demonstrated that Heterohelix was a provisional name and a new supraspecific name is necessary for the globular– chambered heterohelicids.
Remarks: The globular–chambered species of the Santonian– Maastrichtian ornamented with longitudinal leptocostae and aperture bordered by two symmetrically developed orthoflanges are assigned a new name: Ehenbergites, to accommodate a directional lineage that led to the evolution of tests with multichamber growth in the adult stage. Directional lineage Ehrenbergites does not include the the globular–chambered tests, such as “Gümbelina” reussi Cushman 1938 that occur in the upper Cenomanian–lower Campanian sediments, which have the chamber surface ornamented with more continuous leptocostae and aperture bordered by symmetrically developed metaflanges (Fig. 7); “G.” reussi requires taxonomic revision and reassignment at lineage level and for this reason the original assignment is used in this study. Striataella is a genus described by Aliyulla (1977) and although it was separated from the main heterohelicid stock no reason was given for this taxonomic solution; it was unclear to Striataella’s author too, hence the designated type species was assigned to Heterohelix rather than to genus Striataella. Therefore Striataella has no taxonomic significance and is a name that should be abandoned.

References:

Georgescu, M. D. (2013c). Revised evolutionary systematics of the Cretaceous planktic foraminifera described by C.G. Ehrenberg. Micropaleontology. 59: 1-48. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Ehrenbergites Georgescu 2013

Ehrenbergites

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