CATALOG OF ORIGINAL DESCRIPTIONS: Globorotalia loeblichi El-Naggar 1966

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 -> G -> Globorotalia -> Globorotalia loeblichi
Other pages this level: << < G. kilabiyaensis, G. kingmai, G. kolchidica, G. kugleri, G. lacerti, G. lehneri, G. lenguaensis, G. lensiformis, G. lensiformis carpatica, G. lenticularis, G. limbata conferta, G. limbata consutila, G. limbata latiumbilicata, G. limbata oregope, G. lobata, G. loeblichi, G. lupeae, G. magnifica, G. margaritae, G. margaritae evoluta, G. margaritae primitiva, G. marginaculeata, G. marginidentata propelleriformis, G. marginodentata, G. mariae gratiae, G. mariae mariae, G. marksi, G. martinezi, G. martini scandretti, G. mattseensis, > >>

Globorotalia loeblichi

Citation: Globorotalia loeblichi El-Naggar 1966
Rank: species
Type locality: Holotype (fig. 1 a-c) and unfigured paratypes from approximately 240.5 meters above the base of the Gebel Owaina sect ion (27°45'N 32°4 5. 75'E), about 12 km. north of the Nile at El Mahamid, Esna-Idfu region, Upper Egypt.
Type age: Lower Eocene, Libya Group, Globorotalia wilcoxensis Zone. Also occurs in the uppermost Paleocene, Globorotalia aequa/Globorotalia esnaensis Subzone.
Holotype Repository: London, UK; NHM
Type & figured specimens: holotype (fig. 1a-c) P.45615; unfigured paratypes, P.45669-456670.

Linked specimens: London, UK; NHM (PM P 45615) London, UK; NHM (45670) London, UK; NHM (45669)

Current identification/main database link: Morozovella aequa (Cushman and Renz 1942)


Original Description
Diagnosis. - A Globorotalia with small strongly umbilico-convex test; flat, slightly imbricate dorsal side, and distinctly protruding ventralone; extremely narrow umbilicus, and high umbilical shoulder; curved, imbricate dorsal sutures, and radial, in cised ventral ones; crescentic chambers on dorsal side, elongated in direction of coiling and increasing rapidly in size; delicate marginal keel, and delicately papillose surface.

Description. - Test small, planoconvex, umbilico-convex, coiled in a very low trochospire; dorsal side flat, slightly imbricate; ventral side dis tinctly protruding; equatorial periphery roughly ovoid, distinctly lobate with a delicately beaded marginal keel; axial periphery angular, acute; chambers on the dorsal side about 12, rapidly increasing in size and arranged in 2½ dextrally coiled whorls: the initial chambers are small, indis tinct and almost masked by the surface rugosity; the last whorl is composed of 3½, large, crescentic chambers, which are strongly elongated in the direction of coiling; the last chamber constitutes about half the test; on the ventral side, the chambers are 3½, distinctly angular conical, strongly protruding; sutures on the dorsal side strongly curved. delicately beaded and very weakly raised; on the ventral side they are almost straight, radial and strongly depressed; um b ilicus extremely small, deep and open; aperture interiomarginal, extraumbilical-umbilical, a large, crescent ic arch with a narrow delicate lip; wall calcareous perforate; surface delicately but distinctly papillose with the papillae decreasing gradually towards the last chamber.

Size: Maximum diameter 0.30 mm.; minimum diameter 0.22 mm.; thickness 0. 20 mm.

Extra details from original publication
Synonymy

Remarks. - Globorotalia loeblichi El-Naggar is morphologically similar to both Globorotalia lensiformis Subbotina, and Globorotalia quetra Bolli. It is distinguished from the former by its much smaller size, less tightly coiled test. fewer chambers in the last whorl, more lobate periphery, slightly imbricate dorsal side, less developed keel, and less rugose surface. It differs from G. quetra Bolli in its much smaller size; flat, imbricate dorsal side; less lobate periphery; delicate, non-spinose keel, more angular axial periphery, and delicately papillose, non-spinose surface.
Loeblich and Tappan (1957) described a G. aequa Cushman and Renz, from the Paleocene-Lower Eocene of the Gulf and Atlantic Coastal plains of the U.S.A., and of Mexico, forms with a marginal keel, although G. aequa does not have a keel. As can be seen from their figures, these forms probably belong to the present species, to G. quetra Bolli, and to other undescribed forms (see synonymy). Similarly, the form described by Said and Kerdany (1961) as G. triplex (Subbotina)  is possibly G. loeblichi; Acarinina triplex is synonymous with both Globigerina Velascoensis and G. stanei, as mentioned above. Again, although the holotype of Acarinina pseudotopilensis Subbotina is a junior synonym of Globorotalia esnaensis (Le Ray) , the paratype figured by Subbotina (1953, pl. 22, fig. l a-c) most probably belongs to the present species. Hillebrandt (1962) described as Globorotalia (Truncorotalia) aequa simulatilis (Schwager) and Globorotalia (Acarinina) quetra Bolli, forms which probably be long to G. loeblichi.
Globorotalia loeblichi is believed to have evolved from G. aequa Cushman and Renz by the development of a marginal keel, and by the reduction in the surface rugosity and in the size of the umbilicus. On the other hand it is believed to have evolved into G. quetra Bolli by the increase in the size of test; by the development of the slightly concave dorsal side, less tightly coiled test, distinctly spinose surface, spinose keel, and by the reductionof the keel on the last one or two chambers. The paratype figured by Bolli (1957 pl. 19, figs. 4-6) is probably a transitional stage be tween G. loeblichi and G. quetra, and forms mentioned by Bolli as G. cf. quetra may belong to G. loeblichi.

References:

Bolli, H.M., (1957). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation 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. 61-82.

El-Naggar, Z.R., (1966). Stratigraphy and planktonic foraminifera of the Upper Cretaceous-Lower Tertiary succession in the Esna-Idfu region, Nile Valley, Egypt, U. A. R. Bulletin of the British Museum (Natural History) Geology, supplement 2: 1-291.

Hillebrandt von, A., (1962). Das Paleozän und seine Foraminiferenfauna im Becken von Reichenhall und Salzburg. Bayerische Akademie der Wissenschaften Mathematisch-Naturwissenschaftliche Klasse, Abhandlungen, Neue Folge, 108: 1-182.

Loeblich, A.R. & Tappan, H., (1957). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. 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. 173-198.

Said, R. & Kerdany, M.T., (1961). The geology and micropaleontology of the Farafra Oasis, Egypt. Micropaleontology, 7: 317-336.

Subbotina, N., (1953). Foraminiferes fossiles d'URSS Globigerinidae, Globorotaliidae, Hantkeninidae. Bureau de Recherches Geologiques et Minieres, 2239: 1-144.


logo

Globorotalia loeblichi compiled by the pforams@mikrotax project team viewed: 18-9-2018

Taxon Search:
Advanced Search
Short stable page link: http://mikrotax.org/pforams/index.php?id=131176Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics