CATALOG OF ORIGINAL DESCRIPTIONS: Rugoglobigerina (Rugoglobigerina) browni El Naggar 1971

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 -> R -> Rugoglobigerina (Rugoglobigerina) -> Rugoglobigerina (Rugoglobigerina) browni
Other pages this level: R. (Rugoglobigerina) arwae, R. (Rugoglobigerina) badryi, R. (Rugoglobigerina) bronnimanni, R. (Rugoglobigerina) browni, R. (Rugoglobigerina) bulbosa, R. (Rugoglobigerina) pilula, R. (Rugoglobigerina) plana

Rugoglobigerina (Rugoglobigerina) browni

Citation: Rugoglobigerina (Rugoglobigerina) browni El Naggar 1971
Rank: Species
Type locality: Section at Wadi El-Sharawna, on the western slopes of Gebel Owaina, on the right bank of the Nile south of Esna, Esna-Idfu region of the Nile Valley, Upper Egypt.
Type age (chronostrat): Upper Cretaceous, Maastrchtian, Esna Group, Sharawna Shale Formation; holotype (fig. 1) from the Upper Sharawna Shale (upper unit of the formation ); and figured paratypes (figs. 2-10, 13) from the Middle Sharawna Marl (middle unit of the fonnation). Occurs in the middle and upper Maastrichtian rocks of the type area. Common.
Type specimens: Pl. 17, figs. 1-10, 13
Type repository: London, UK; NHM
Described on page(s) : 484-5

Current identification/main database link: Rugoglobigerina rugosa (Plummer, 1927)


Original Description

Diagnosis - A Rugoglobigerina (Rugoglobigerina) species distinguished by its small to medium sized, low trochospiral, quadrate test; 4-4Yz regularly increasing or only very slowly increasing cham-bers in the outer whorl and rapidly increasing chambers in the inner one; depressed spiral suture and radial, incised intercameral ones; small umbilicus and delicate distinctly developed meridional costellae.

Description - Test medium-sized, coiled in a low trochospire; dorsal side almost flat to slightly concave with a depressed inner part and inflated later chambers; ventral side inflated, protruding; equatorial periphery quadrate, lobate; axial periphery rounded; chambers on the dorsal side 11, arranged in 2 dextrally coiled whorls; the initial chambers are small, globigerine and inflated; they increase regularly in the early part until the beginning of the second whorl when the rate of increase is somewhat decelerated; the outer whorl is composed of 4, globigerine, inflated chambers which increase regularly in size as added; the last chamber is somewhat elongated in the direction of coiling; on the ventral side, the chambers are 4, globigerine, inflated and increase regularly in size; spiral suture depressed; inter-cameral sutures on both sides almost straight, radial and depressed, more so on the ventral side where the 4, depressed sutures join the umbilical periphery in a cross form; umbilicus small, covered by a complex system of tegilla of which remnants are still preserved; primary aperture interiomarginal umbilical covered by tegilla, remnants of which are still preserved; surface rugose covered by well developed meridional costellae which are somewhat reduced on the last chamber; wall calcareous, perforate, hyaline; except for the imperforate tegilla and surface rugosity.


Size: Maximum diameter 0.355 mm.: minimum diameter 0.320 mm. thickness 0.115 mm

Etymology: The species is named after the late Dr. NOEL K. BROWN, Jr.

Extra details from original publication

Remarks. - Rugoglobigerina (R.) browni El-Naggar is distinguished from the morphologically similar Rugoglobigerina ( R.) rugosa (Plummer) [Globigerina rugosa, 1927] by its smaller, thinner, quadrate test, much narrower umbilicus, and less rugose surface. From R. (R.) macrocephala it is distinguished by its less rapid rate of chamber growth in the outer whorl; a much smaller last chamber, which can be either larger or smaller than the penultimate one; its quadrate appearance, more or less perpendicular sutures on the ventral side, smaller umbilicus and rougher surface. From R. (R.) ornata it can be easily separated by the above mentioned characters as well as by its less developed surface rugosity.

Stratigraphical range - Rugoglobigerina (R.) browni
is common in the Middle and Late Maastrichtian rocks of the Esna-Idfu region, Nile Valley, Egypt, U. A. R.


Editors' Notes
content migrated from chronos

References:

El-Naggar, Z. R. (1971b). The genus Rugoglobigerina in the Maastrichtian Sharawna Shale of Egypt. In, Farinacci, A. (ed.) Proceedings of the Second Planktonic Conference, Roma 1970. Edizioni Tecnoscienza 477-537. gs


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Rugoglobigerina (Rugoglobigerina) browni compiled by the pforams@mikrotax project team viewed: 29-11-2020

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