Catalog - Globigerinanus phodoaplatus

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinanus phodoaplatus Ouda 1978

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 -> Globigerinanus -> Globigerinanus phodoaplatus
Other pages this level: G. bullatus bullatus, G. bullatus expansus, G. loxophodellus, G. multiaperturus, G. phodoaplatus, G. sphaeroides, G. sudri maturus, G. sudri sudri

Globigerinanus phodoaplatus

Citation: Globigerinanus phodoaplatus Ouda 1978
Rank: species
Type specimens: Plate 2, figs. 2a-4c, and 5
Type age (chronostrat): upper part of the Ayun Musa Formation, Sudr East Well 2, at depth 820 feet
Type locality: Sudr East Well 2, Sinai, Egypt; 29.55N; 32.85E
Type repository: Madrid; Geological Service, E. N. Adaro, Serrano, 116, Madrid-6, Spain

Current identification:


Original Description

Test free, of small to medium size and consists of three whorls of regularly enlarging, inflated, slightly embracing chambers, arranged in a low trochospire with four loosely- coiled chambers in the last two whorls. In aquatorial profile, the test is subquadrate to subtrapezoidal and the equatorial periphery is quadrilobate. In axial view, the test is oval to ovate; the ventral side is slightly more convex than the dorsal side. The chambers are subglobular to suboval, being slightly inflated ventrally than dorsally, lacking a distinct dorsa-peripheral shoulder. In some relatively tighter-coiled specimens, the dorsal side being more convex than the ventral side and the final chambers become increasingly longer than broad. The sutures are distinct and depressed throughout; they are initially curved on the dorsal side, later becoming subradial. The ventral intercameral sutures are deeply depressed and subradial. The umbilicus is broad, deep and characteristically quadrate in outlines. The primary aperture beneath the bulla is a moderately high to high, symmetrical arch which is laterally restricted to the breadth of the umbilicus. A simple, flattened bulla of subquadrate outlines is attached to the apertural face of the final chamber, extending across to the umbilical margin of the opposing antepenultimate chamber, covering partially or completely the umbilicus. The bulla is only slightly convex, and when narrow, appears to be merely arched. In some specimens, the breadth of the bulla is less than that of the umbilical limits (pl. 2, fig. 3a)), but in others the bulla is extending· to, and even beyond the umbilical limits (pl. 2, fig. 4a}. Two narrow, slit-like accessory apertures are often present, one is placed between the bulla and the entire umbilical margin of the first chamber of the last whorl, and the other is placed between the· bulla and the entire umbilical margin of the penultimate chamber. In few specimens the bulla seems to be much longer than broad and attached to the apertural face of the final chamber only, covering partially the umbilicus and leaving a single long and narrow opening between the suture of the bulla and the entire umbilical margin of the first three primary chambers of the last whorl (pi. 2, fig. 2a). The dorsal side of the test shows distinct supplementary sutural apertures; they are two or three apertures usually confined to the last few chambers, one per chamber. These supplementary apertures are low to moderately high arches, often bordered by a thin rim, each aperture is placed over two sutures between three earlier chambers. The wall of the primary chambers is calcareous and moderately to coarsely perforate, its surface is punctate and distinctly hispid. The wall of the bulla is comparatively thinner, smooth to finely perforate and weakly hispid.

Size:
Maximum diameter of holotype is 0.45 mm; minimum diameter is 0.4 mm; thickness is · 0.35 mm. Paratypes range from 0.3 mm to 0.5 mm in maximum diameter, from 0.3 mm to 0.4 mm; in minimum diameter, and from 0.27 mm to 0.37 mm in thickness.

Etymology:

Extra details from original publication
The smaller size of the test, the typically quadrilobate form of tpe equatorial periphery, the subglobular, very less embracing and less rapidly enlarging chambers, the quadrate shape of the umbilicus, and the flattened umbilical bulla which is only slightly convex or merely arched, and which has two narrow, slit-like accessory infralaminal apertures, are all among the many characteristic features which serve to distinguished this species from members of Globigerinanus sudri, new species.

OBSERVED STRATIGRAPHIC RANGE Late Burdigalian (Early Miocene) to Langhian (Middle Miocene).

Editors' Notes

References:

Ouda, K. (1978). Globigerinanus, a new genus of the Globigerinidae from the Miocene of Egypt. Revista Española de Micropaleontología. 10: 355-378. gs V O


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Globigerinanus phodoaplatus compiled by the pforams@mikrotax project team viewed: 30-11-2022

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