Catalog - Globigerina haynesi

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Globigerina haynesi

Citation: Globigerina haynesi El-Naggar 1966

Type specimens: holotype (fig. 5a-d) P.45576; unfigured paratypes, P.45577.

Type sample (& lithostrat): pper Owaina Shale. Rare in the uppermost part of the Lower Paleocene (Danian) and common to abundant throughout the Middle and Upper Paleocene.

Type age (chronostrat): Upper Paleocene, Globorotalia velascoensis Zone, u

Type locality: Holotype (fig. 5a-c) and unfigured paratypes recovered from 20 1.5 to 208 meters above the base of the Gebel Owaina section (27°45'N 32° 45.75'E), about 12 km. north of the Nile at El Mahamid, Esna-Idfu region, Upper Egypt.

Diagnosis. - A Globigerina with relatively raised dorsal side and moderately inflated ventral one; quadrate, lobate equatorial periphery; depressed sutures; very narrow umbilicus and delicately papillose surface.

Description. - Test medium-sized, coiled in a relatively high trochospire; dorsal side subconical, inflated; ventral side quadriglobular, moderately inflated; equatorial periphery quadrate, distinctly lobate, axial periphery rounded; chambers on dorsal side 15, arranged in 2_ dextrally coiled whorls and increasing moderately in size; the initial chambers are small, globular, inflated and are followed by subglobular or rather ovoid, large ones; the last whorl is composed of 4, subglobular and strongly inflated chambers: on the ventral side the chambers are 4, large, globular, strongly overlapping and moderately inflated; sutures on the dorsal side slightly curved, strongly depressed; on the ventral side they are almost straight, radial and strongly incised; umbilicus extremely smali, almost indistinct, slit-like, shallow and open; aperture interiomarginal, umbilical, in the form of a long narrow arch with a delicate, small lip; wall calcareous, perforate; surface finely pa pillose. "

Maximum diameter 0.37 mm.: minimum diameter 0.34 mm.; thickness 0.26 mm.

Main variation. - Chambers 12-16, arranged in 2½-3 tightly coiled whorls, and increasing moderately in size. The last whorl is composed of 3½-4 chambers, 4 being most common; the last chamber is usually slightly smaller than the penultimate. Coiling is random with a tendency to dextral coiling: (of 77 specimens studied, 49 coiled dextrally).

Remarks. - Globigerina haynesi El-Naggar was probably confused with one or more of the following distinct, but morphologically similar species: Globigerina bacuana Khalilov : Globigerina spiralis Bolli: Globigerina aquiensis Loeblich and Ta ppan: Globigerina chascanona Loeblich and Tappan.
It is distinguished from G. bacuana by its delicately papillose surface, high dorsal side, and raised initial whorls. Globigerina spiralis is distinguished by its smooth surface, greater number of chambers and of whorls, and more tightly coiled test. Globigerina aquiensis which is morphologically very similar to the present species, has a finely hispid surface instead of a delicately papilloseone; G. chascanona is distinguished by its prominently spinose surface.
Globigerina haynesi is believed to have evolved from G. spiralis Bolli; specimens of G. spiralis with a faintly papillose surface are believed to be transitional to G. haynesi and the stratigraphical ranges of the two species favour this hypothesis. On the other hand, G. haynesi probably evolved into G. velascoensis Cushman by developing a more tightly coiled test, with an angular, depressed spiral suture and a strongly appressed last chamber.""

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). supplement 2: 1-291. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina haynesi El-Naggar 1966

Globigerina haynesi

References:

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