Catalog - Biglobigerinella sigali

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Biglobigerinella sigali

Citation: Biglobigerinella sigali Chevalier 1961

Type specimens: Pl. 1, figs. 19-23: 19a-b, holotype, umbilical and apertural views; 20-23, paratypoids.

Type age (chronostrat): Lower Cretaceous, Aptian, lower Gargasian.

Type locality: A section at the hill at Gargas, Apt region, western Provence, southeast France. Found also in sections at La Bedoule, near Cassis, southeast of Marseille ; at Rove; in the valley of Cloche-Font-douille; at Pierre Fiche; and at the Pin Farm; all in western Provence, southeast France.

Type repository: Paris; Laboratory of Micropaleontology University of Paris, France.

Translated from French using Google Translate original text below

Diagnosis. - Species characterized by its involute winding consists of a large number of chambers increasing slowly in size.

"Diagnose. - Espece caracterisee par son enroulement involute compose d'un nombre eleve de loges croissant lentement de taille.

"Dimensions. -
Grand diametre Petit diametre Epaisseur en
vue orale
Holotype 0.371 0.314 0.228
Paratypoides 0.371 0.314 0.257
0.371 0.314 0.314

Translated from French using Google Translate original text below

Description. - Limestone test, planispiral, finely perforated, involute, biombilic. Chambers of the last lap more or less globular, numbering seven to eight, and regularly slowly increasing in size. At the base of the last box, less bulging, and wider, are placed two small globular, symmetrical chambers, contiguous to each side of the winding plane, and shifted towards the center of the test with respect to the outer coil. The twin chambers in the holotype are of almost equal size to that of the last normal lodge. The subrectiline sutures little depressed between the first boxes deepen between the last ones. Convex oral face, wider than it is tall. Broad umbilicus, usually shallow but distinct. inconspicuous opening, probably located at the base of the last chamber.

"Description. - Test calcaire, planispirale, finement perfore, involute, biombilique. Loges du dernier tour plus ou moins globuleuses, au nombre de sept à huit, augmentant lentement et regulierement de taille. A la base de la derniere loge moins renflée, plus elargie, se placent deux petites loges globuleuses, symetriques, accolées de chaque cote du plan d'enroulement, et decalees en direction du centre du test par rapport a la spire exterieure. Les loges jumelles chez l'hol otype, sont de taille presque egale a celle de la derniere loge normale. Les sutures subrectilignes peu deprimees entre les premieres loges s'approfondissent entre les dernieres. Face orale convexe, plus large que haute. Ombilic large, generalement peu profond mais bien distinct. Ouverture peu visible, probablement située à la base de la dernière loge.

"Dimensions. - Grand diametre Petit diametre Epaisseur en vue orale Holotype 0.371 0.314 0.228 Paratypoides 0.371 0.314 0.257 0.371 0.314 0.314

Translated from French using Google Translate original text below

Variations.-These are numerous and result in the number of chambers plus or high hands and the variable development of the two twin chambers attached to each side of the winding plane, as well as by the more or less strong widening of the In the last round, some of them present at the end of the last lap, with more flattened, enlarged chambers, separated by deep sutures with a beginning of mid-division of the last chamber. It is a new species or an evolving form that has not yet reached the definitive morphological characteristics found in most of the individuals we describe. It seems for the time being more logical to consider them as stages of mutation. On the path that leads to typified individuals with separate twin chambers.

Reports and differences. - A. Ten Dam and J. Sigal have described Biglobigerinella algeriana in 1949, whose characteristics are similar to those of ours, but which differs however in the smaller number of its chambers, in its umbilicus and in smaller diameters. This species also differs from Biglobigerinella barri Bolli, Loeblich and Tappan in having less globular periphery chambers and rectilinear sutures.

"Variations. - Celles-ci sont nombreuses et se traduisent par le nombre de loges plus ou mains eleve et le developpement variable des deux loges jumelles accolees de chaque cote du plan d'enroulement, ainsi que par l'elargissement plus ou moins fort du test au cours du dernier tour. Certaines fonnes present ent sur la fin du dernier tour, des loges plus aplaties, elargies, separees par des sutures profondes avec un debut de division mediane de la derniere loge. On pourrait se demander s'il s'agit d'une nouvell e espece ou d'une forme evoluee n'ayant pas encore atteint les caracteres morphologiques definitifs constates dans la plupart des individus gue nous decrivons. Il sembl e pour l'heure plus logique de les considerer comme des stades de mutation sur la voie qui mene aux individus typigues a loges jumelles distinctes.

Rapports et differences. - A. Ten Dam et J. Sigal ont decrit en 1949 Biglobigerinella algeriana dont les caracteres voisinent avec ceux de la notre, mais qui differe cependant par le nombre plus restreint de ses loges, par son ombilic ainsi que par des mesures diametrales moins elevees. Notre espece differe egalement de Biglobigerinella barri Bolli, Loeblich et Tappan, par ses loges de la peripherie moins globuleuses et par ses sutures rectilignes.

References:

Chevalier, J. (1961). Chevalier, J. (1961). Quelques nouvelles espèces de Foraminifères dans le Crétacé inférieur méditerranéen. Revue de Micropaléontologie. 4(1): 30-36. Revue de Micropaléontologie. 4(1): 30-36. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Biglobigerinella sigali Chevalier 1961

Biglobigerinella sigali

References:

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