Catalog - Globotruncana fareedi

CATALOG OF ORIGINAL DESCRIPTIONS: Globotruncana fareedi 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 -> Globotruncana -> Globotruncana fareedi
Other pages this level: << < G. concavata cyrenaica, G. conica, G. conica plicata, G. contusa galeoidis, G. contusa patelliformis, G. contusa scutilla, G. contusa witwickae, G. convexa, G. culverensis, G. dentata, G. dorreeni, G. dupeublei, G. erevanica, G. falsocalcarata, G. falsostuarti, G. fareedi, G. flexuosa, G. fornicata, G. fornicata ackermanni, G. fornicata cesarensis, G. fornicata globulocamerata, G. fornicata manaurensis, G. fornicata motai, G. fornicata plummerae, G. fresnoensis, G. fundiconulosa, G. gagnebini, G. gansseri, G. gansseri gandolfii, G. gansseri subgansseri, G. globigerinoides> >>

Globotruncana fareedi

Citation: Globotruncana fareedi El-Naggar 1966
Rank: Species
Type locality: Holotype (fig. 4a-d) and unfigured paratypes from approximately 103.5 meters above the base of the Wadi El-Sharawna section (25° 141N 32°44'E), about 19 km. southeast of the Nile at Esna, Esna-Idfu region, Upper Egypt.
Type age (chronostrat): Upper Cretaceous, Maestrichtian, Rare to common in the Globotruncana fornicata Zone (Lower Maestrichtian), common to abundant in the Globotruncana gansseri Zone (Middle Maestrichtian), and dies out in the basal part of the Globotruncana esnehensis Zone (Upper Maestrichtian).
Type sample (& lithostrat): upper Sharawna Shale.
Type specimens: holotype (fig. 4a-d) P.45528, and unfigured paratypes, P.45666.
Type repository: London, UK; NHM

Linked specimens: London, UK; NHM (45528) London, UK; NHM (45666)

Current identification/main database link: Globotruncana esnehensis Nakkady 1950


Original Description
Test large, circular, biconvex; dorsal side arched ; ventral side moderately protruding; periphery circular, distinctly lobate, transversally acute, with a single well-developed, beaded keel; chambers on the dorsal side 18, arranged in 3 dextrally coiled whorls; initial chambers small, inflated, globigerine, followed by roughly quadrangular chambers which increase regularly in size; the last whorl is composed of 6 large, quadrangular chambers which are very slightly elongated in the direction of coiling; on the ventral side the 6 large, roughly quadrangular chambers are moderately inflated especially around the umbilicus, and taper out gradually towards the periphery; sutures on the dorsal side slightly curved in the early part, nearly straight in the last part, raised and beaded; on the ventral side the sutures are very slightly curved or nearly straight, radial and strongly depressed especially towards the periphery, while towards the umbilicus they are slightly raised, thickened and beaded before curving around the umbilicus and joining to form a much thickened, raised, beaded umbilical flange; umbilicus wide, deep, roughly hexagonal, covered by complex tegilla of which remnants are still preserved; primary apertures interiomarginal, umbilical; tegilla with accessory apertures only poorly preserved; wall calcareous, perforate, except for the imperforate keel and tegilla; surface smooth and finely porous.

Size: Maximum diameter 0.47 mm.; minimum diameter 0.44 mm.: maximum thickness 0. 22 mm

Extra details from original publication


Main variation
. - The test may be strongly or weakly biconvex; chambers 18-24 a rranged in 3-4 whorls, (a ll the specimens studied coiled dextrally). The beading of the sutures and the k eel may be heavy throughout or may fade out gradually towards the last chamber. The rate of growth may be slow and constant, leading to a regular increase in chamber size, or it may be rapid in the later stage, producing relatively bigger chambers in the last whorl. The dorsal surface of each of the chambers in the last whorl (not the dorsal side of the test) is flat, slightly convex, or even slightly concave. The umbilicus is moderate to large and the ventral sutures are either slightly or strongly depressed.
Remarks - Globorruncana fareedi El-Naggar morphologically resembles both G. stuarti stuarti (de Lapparent) [Rosalina stuarti, 1918] and G. esnehensis Nakkady and Osman. It is distinguished from the former by its equally biconvex test, lobate periphery, quadrangular rather than trapezoidal chambers on the dorsal side; short, depressed radial sutures on the ventral side and less tangential ones on the dorsal; its much wider umbilicus and imbricate umbilical fl ange. lt differs from G. esnehensis in having a biconvex test, a much lower dorsal side and a more protruding ventral one, quadrangular chambers on the ventral side and less inflated ones on the dorsal, much wider umbilicus and an imbricate umbilical flange. Globotruncana falsostuarti Sigal has a similarly wide umbilicus and discontinuous umbilical flange, but is distinguished by its double keel and more protruding ventral side.
Globotruncana fareedi was probably confused in the past with both G. rosetta rosetta (Carsey) [Globigerina rosetta, 1926 ] and G. falsostuarti Sigal. However, G. rosetta rosetta is distinguished by its perfectly plano-convex, umbilico-convex test; double keel on the early chambers of the last whorl, becoming single on the last chambers: its flat crescentic chambers on the dorsal side, and angular conical, strongly protruding ones on the ventral; its narrower umbilicus, and slightly rougher surface. The forms described as G. rosetta (Carsey) by Keller (1946) and as G. rosetta insignis by Gandolfi (1955) are not related to G. rosetta, but probably belong to the present species, although Gandolfi's form shows a flatter dorsal side and a slightly narrower umbilicus. Again, G. falsostuarti Sigal was so briefly described that its diagnostic features were not really known, and thus it has often been misinterpreted. The forms figured by Knipscheer (1956) as G. falsostuarti are different from Sigal 's holotype, but may well belong to the present species, while the form described as G. rosetta pembergeri by Papp and Kupper (1953) most probably belongs to G. falsostuarti Sigal. Through the kindness of Dr. J. Sigal, the type specimens of G. falsostuarti, which are in his personal collection, were examined by the present author. This examination showed that: 1. The holotype of G. falsostuarti is distinguished by its unequally biconvex test; strongly protruding ventral side; two closely spaced keels, the ventral one of which is slightly shifted towards the inner side of the test and is reduced on the last chamber; its highly beaded keels and dorsal sutures; inclined peripheral band; raised, beaded, discontinuous umbilical flange; and inclined, raised, beaded ventral sutures. It is more closely related to G. area (Cushman) [Pulvinulina area, 1926 ] than to G. stuarti stuarti (de Lapparent). 2. The paratypes of G. falsostuarti include forms belonging to  (de Lapparent), G. conica White, G. esnehensis Nakkady and Osman and G. fareedi.
The similarity in the shape of the chambers and the sutures on both sides, the distinctly lobate, circular periphery and the entirely single keel, suggest that G. fareedi has possibly evolved from G. elevata (Brotzen) [Rotalia elevata, 1934] in early Maestrichtian time, although its evolution from G. stuarti stuarti (de Lapparent) is not excluded. Again, G. fareedi may have evolved into G. esnehensis Nakkady and Osman in early Middle Maestrichtian time by increasing the convexity of the dorsal side and flattening the ventral side. The diagnostic features and stratigraphical ranges of these species favour these propositions."

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Editors' Notes
content migrated from chronos

References:

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. gs


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Globotruncana fareedi compiled by the pforams@mikrotax project team viewed: 19-9-2021

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