Catalog - Cassigerinella globolocula

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.

Other pages this level: C. boudecensis, C. eocaenica, C. globolocula, C. regularis, C. spinata

Cassigerinella globolocula

Citation: Cassigerinella globolocula Ivanova, in Bykova et al. 1958

Type sample (& lithostrat): Kosmach Series, and occurs also in the lower Vorotyshcha Series

Type age (chronostrat): Upper Oligocene

Type locality: Along the Vorotyshche River, Carpathian Mountains, USSR

Test small, tumid, with a broadly oval or rounded outline, with boldly projecting chambers. Peripheral margin rounded, sinuous. The early stage of growth of the test is spiral; the early chambers are not distinct in exterior view, because they are in the middle of the test. In broken specimens one can see that the early stage consists of one and one-hal f to two spiral whorls. The first whorl is very small, barely distinguishable at a magnification of X 110. The following whorls of the spiral portion consist of five or six closely adjoining chambers. rapidly increasing in size.

Spiral portion in adult specimens most frequently visible on one side of the test. In forms with an uncoiled later portion, that is, becoming evolute, the early whorls are seen on both sides of the test. In the later stage of growth the test consists of alternating chambers, arranged in a zigzag shape, and, at the same time, in a spiral. Chambers of the early portion have a triangular outline; in the later portion they are strongly tumid, bubble-shaped, nearly spherical, rapidly increasing in size. Sutures thin, simple, weakly depressed, arcuate or straight, radial; in the later portion of the test they are strongly depressed, curved. Aperture semicircular, situated at the marginal suture, near the peripheral margin. Each subsequent chamber in the adult stage of the test has the apertural portion situated on the opposite side in relation to the preceding and subsequent cllambers. Wall thin, finely perforate, without supplementary test material.

Diameter of holotype 0.08-0.14mm; thickness 0.03-0.08. Specimens most frequently bave a diameter of 0.10-0.11 mm., and a thickness of 0.06-0.07 mm.

Two basic types of tests are distinguishable. The first is strongly tumid, nearly spherical, with a rounded outline; as a rule, these are the largest. The second are relatively flattened, with an oval outline, and, as a rule, are the smallest. In the first type the chambers of the adult stage of the test completely overlap the earlier whorls, with the exception of the final one or two or rarely last three chambers of the early whorl. In the second type, the chambers of the adult stage barely overlap the earlier whorls of the spiral which are, therefore, well visible. The size of the chambers of the adult stage may increase in different ways; they may be very distinct or nearly uniform. There are also specimens in which the final chamber is smaller than the preceding ones. Aperture may differ in being displaced toward the peripheral margln. There are specimens in which the aperture is situated near the middle of the marginal suture. Large and tumid forms, in which the early portion is not seen, are very similar to Cassidulina, in which the described species was placed for a long time. The cassidulinid specimens are found in the Kosmach deposits. Cassigerinella is typical for the lower Vorotyshcha Series.

References:

Bykova, N . K., et al. (1958). Новые роды и виды фораминифер - New genera and species of foraminifera. Микрофауна CCCR СБОРНИК IX, Microfauna of the USSR - part IX. Trudy Vsesoyuznego Neftyanogo Nauchno-Issledovatel'skogo Geologo-Razvedochnogo Instituta (VNIGRI). 115: 5-106. gs O

CATALOG OF ORIGINAL DESCRIPTIONS: Cassigerinella globolocula Ivanova, in Bykova et al. 1958

Cassigerinella globolocula

References:

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