Catalog - Globigerina crassa

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Globigerina crassa

Citation: Globigerina crassa Shutskaya 1970

Type specimens: holotype (fig. 4a-c), no. 1581-1-62

Type sample (& lithostrat): Lower Danat Subsuite

Type age (chronostrat): Upper Paleocene, Kachan Stage, Acarinina tadjikistanensis djanensis Zone

Type locality: Malyy Balkhan Mts., western Turkmenia, USSR

Type repository: probably deposited in the collec- tions of the All-Union Scientific-Research Geological-Prospecting Petroleum Institute (VNIGNI), Moscow

Translation from the Russian. - Test medium-sized to large (0.35-0.45 mm.), tlattened dorsally, convex ventrally, subtriangular: a) elongation coefficient 1.1-1.2: b) broadening coefficient 1.3-1.5. Structure of initial part of test globigerinoid, low-trochoid. 7-8 chambers in initial part of test. 3.5 chambers. rapidly and nonuniformly enlarging, in the last whorl. Relationship of dimensions of individual elements of the last whorl: a) ratio of width of largest (penultimate) chamber to the width of the last chamber 1-1.3; b) last chamber either subtriangular or hemispherical, more extended lengthwise than in width, ratio 1.1-1.3. Apertural part of inner margin of last chamber lies obliquely relative to umbilicus. Side surface of last chamber broadly rounded and oval, sometimes extended across the width. Its height is greater than the height of the preceding part of the test. Shape of penultimate chamber subquadrate, of first one rounded; surface of chambers flattened-intlated. Chambers freely arranged. Intercameral sutures broad, not too deep. Umbilical depression broad. Outer margin coarsely scalloped, in the initial part of the last whorl the outer margin is narrow. Aperture marginal, oblique, slitlike, short, above the half-chamber, does not reach the middle of the peripheral margin. Pores comparatively small.

Globigerina bulloides d'Orbigny. - White, 1928, Jour. Pal., val. 2, no. 3. p. 192, pl. 27, fig. 12a, b.
Globigerina triloculinoides Plummer. - Loeblich and Tappan, 1957 (part), U.S. Nat. Mus., Bull.. no. 215, p. 183, pl. 46, fig. 1a-c.

Variation. - Expressed in differing test dimensions: very large tests (up to 0.45 mm.) with a large broadening coefficient (up to 1.5) are commonly found.

Comparison. - The specimen figured by Loeblich and Tappan (1957) as G. triloculinoides in association with foraminifera from the Coal Bluff Formation is referred to the species described. In both the American specimen of this species and the specimens in the material studied, besides the three chambers the half-chamber takes part in building the last whorl; the maximum width of the spire in the last whorl is reached in the area of the next-to-last chamber, the aperture is oblique, slitlike. The same features also characterize the test described by White (1928) as G. bulloides. Globigerina crassa differs from G. gerpegensis by having a broader penultimate chamber and a subtriangular test.

References:

Loeblich, A. R. & Tappan, H. (1957b). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin . 215: 173-198. gs V O

Shutskaya, E. K. (1970a). Morphologic groups and descriptions of species of Globigerina and Acarinina in the lower Paleogene of the Crimea, the Caucasus Foreland, and western Central Asia. Trudy Vsesoyuznego Neftyanogo Nauchno-Issledovatel 'skogo Geologo-Razvedochnogo Instituta (VNIGRI). 69: 79-113. gs

White, M. P. (1928). Some Index Foraminifera of the Tampico Embayment Area of Mexico. Journal of Paleontology. 2(3): 177-215. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina crassa Shutskaya 1970

Globigerina crassa

References:

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