Catalog - Rugoglobigerina reicheli reicheli

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Rugoglobigerina reicheli reicheli

Citation: Rugoglobigerina reicheli reicheli Bronnimann 1952

Type specimens: 334860; Plate 3, figs.10-12 Text figs.4,5

Type sample (& lithostrat): Globotruncana mayaroensis zone. Abundant Globotruncana mayaroensis zone. Abundant Globotruncana mayaroensis zone.

Type age (chronostrat): Maastrichtian; Globotruncana mayaroensis zone,

Type locality: Trinidad Leaseholds Ltd. Catalogue nos. 155591-155594, subsurface samples from Guayaguayare area, southeastern Trinidad, B.W.I.

Type repository: Washington; USNM

The last volution of the small to medium-sized low trochoidal test comprises 5-6 chambers. Umbilical and spiral sides are well-defined. About 2 whorls can be counted on the centrally slightly depressed spiral side. No details of the initial portion are discernible dur to the coarsely rugose surface. The ultimate chamber can be larger or of the same size or even smaller than the penultimate chambers of the last whorl are of conic shape. The adjoining chambers are peripherally rounded and truncate at the apertural side. The umbilicus is deep, usually filled with matrix. Remains of the delicate covering plate were noted. The straight sutures are depressed, thus producing a lobulate outline. The large arcuate aperture of the end chamber, with a small lip-like projection, opens into the umbilicus. The apertures of the preceding chambers are not known. The walls appear to be thick, and the surface is coarsely rugose. The rugosities of the inflated last chambers are arranged in meridional rows radiating from a center on the surface toward the edges fo the aperture. The investigated specimens are invariably dextrally coiling.

The maximum diameter of the tests, including the spinelike projections, ranges from 0.325 mm. to 0.37 mm.

This species is named after Dr. M. Reichel for his contribution to the knowledge of the Upper Cretaceous genus Schackoina Thalraann.

Remarks. Although the adult stage is Globigerina-like,this subspecies still shows in the early chambers of the last volution indications of hantkeninoid features similar to those described from the subgenus Plumnierella.
It is conceivable that R. reicheli reicheli represents a transitional form between the two groups.The identical rugose ornamentation suggests that both subgenera are genetically related.The central type differs by the hantkeninoid early chambers from the other forms of the reicheli group'

References:

Brönnimann, P. (1952c). Globigerinidae from the Upper Cretaceous (Cenomanian-Maestrichtian) of Trinidad, B. W. I. Bulletins of American Paleontology. 34(140): 1-70. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Rugoglobigerina reicheli reicheli Bronnimann 1952

Rugoglobigerina reicheli reicheli

References:

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