Catalog - Globorotalia (Turborotalia) peripheroronda

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.

Globorotalia (Turborotalia) peripheroronda

Citation: Globorotalia (Turborotalia) peripheroronda Blow & Banner 1966

Type specimens: Plate 1, figure 1a-c; plate 2, figures 1-3.

Type sample (& lithostrat): Auger sample RM. 19304; within the lowest part of the Husito Marly Clay Member (Siphogenerina transversa Zone), Pozón Formation.

Type locality: El Mene - Pozón Road traverse, eastern Falc6n, Venezuela (see Map no. 4, Blow, 1959)

Type repository: Washington, USNM

The test of the holotype (plate 1, figure la-c) consists of nearly three whorls of regularly enlarging chambers, six in each whorl. Successive whorl heights (measured dorsally, from the proloculus) are in the approximate ratios I:4:6. The test is completely evolute dorsally, and the dorsal surface is uniformly perforate; there is no conspicuous deposit of thick, secondary laminae to obscure the early whorls, and there are no sutural limbations of imperforate shell material. The dorsal surface is very slightly convex, and the dorsal sutures are narrowly depressed, the dorsal chamber walls being slightly inflated. The dorsal intercameral sutures meet the lobulate spiral suture at right angles, but they are distally smoothly recurved, meeting the periphery at angles of about 45°. The periphery is weakly lobulate, uniformly perforate, without carina or pseudocarina, and bluntly rounded. The ventral surface is more convex than the dorsal surface, the ratio of ventral to dorsal convexity being about 2:I. The ventral side is completely involute, only the six chambers of the last whorl being visible. The ventral intercameral sutures are narrowly and shallowly depressed and are gently and smoothly curved or sinuous, meeting both the periphery and the narrow, almost closed umbilicus at broad angles (approaching right angles). The ventral chamber walls are uniformly perforate and smooth. Each possesses a low umbilical shoulder, and the area between this shoulder and the periphery is flat or slightly concave in the earlier chambers of the last whorl, flat or slightly convex in the later chambers (this area of the antepenultimate chamber is abnormally swollen). The apertural face is not separated from the ventral face of the last chamber by any change of texture, nor is it separated by an abrupt change of slope. It is smoothly convex and is indistinctly delimited from the rounded periphery. The narrow interiomarginal aperture extends from the umbilicus to the ventral margin of the periphery of the last chamber and ofthe penultimate whorl; the aperture is furnished throughout its length with a thin, uniformly developed lip.

The maximum diameter of the test is 0.31 mm.

Globorotalia barisanensis [sic] LeRoy. - STAINFORTH, 1948, p. 120, pi. 26, figs. 24-26 (not G. barisanensis LeRoy, 1939).
Globorotalia fohsi barisanensis LeRoy. - BOLLI, 1950, p. 88, pi. 15, figs. 5, 6a-c.- BOLLI, 1957, p. 119, pi. 28, fig. Sa-c (not G. barisanensis LeRoy, 1939).
Globorotalia fohsi barisanensis (LeRoy). - BLOW, 1959, p. 212, pi. 17, figs. 110, 111a-c (not G. barisanensis LeRoy, 1939).
Globorotalia (Turborotalia) fohsi barisanensis (LeRoy).- BANNER and BLOW, 1959, p. 22, pl. I, fig. la-b (not G. barisanensis LeRoy, 1939).

Comparison of species: G. ( T.) peripheroronda differs from both G. ( T.) mayeri and G. ( T.) siakensis in possessing a more compressed test, circumferentially shorter chambers (in dorsal view), and dorsal intercameral sutures which are strongly and smoothly recurved, not straight and oblique.

References:

Banner, F. T. & Blow, W. H. (1959). Banner, F. T. & Blow, W. H. (1959). The classification and stratigraphical distribution of the Globigerinaceae. Palaeontology. 2(1): 1-27. Palaeontology. 2(1): 1-27. gs

Blow, W. H. & Banner, F. T. (1966). Blow, W. H. & Banner, F. T. (1966). The morphology, taxonomy and biostratigraphy of Globorotalia barisanensis LeRoy, Globorotalia fohsi Cushman and Ellisor, and related taxa. Micropaleontology. 12(3): 286-302. Micropaleontology. 12(3): 286-302. gs

Blow, W. H. (1959). Blow, W. H. (1959). Age, correlation, and biostratigraphy of the upper Tocuyo (San Lorenzo) and Pozon Formations, eastern Falcon, Venezuela. Bulletins of American Paleontology. 39(178): 67-251. Bulletins of American Paleontology. 39(178): 67-251. gs

Bolli, H. M. (1950a). Bolli, H. M. (1950). The direction of coiling in the evolution of some Globorotaliidae. Contributions from the Cushman Foundation for Foraminiferal Research. 1(3&4): 82-89. Contributions from the Cushman Foundation for Foraminiferal Research. 1(3&4): 82-89. gs

Stainforth, R. M. (1948a). Stainforth, R. M. (1948). Applied micropalaeotology in coastal Ecuador. Journal of Paleontology. 22: 113-151. Journal of Paleontology. 22: 113-151. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globorotalia (Turborotalia) peripheroronda Blow & Banner 1966

Globorotalia (Turborotalia) peripheroronda

References:

Add Comment

Comments