Catalog - Globigerina elongata Shutskaya

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Globigerina elongata Shutskaya

Citation: Globigerina elongata Shutskaya 1970

Type specimens: holotype (fig. 3a-c), no. 1159-1-62

Type sample (& lithostrat): Middle Danat Subsuite

Type age (chronostrat): Lower Eocene, Bakhchisarayan Stage, Globigerina subbotinae 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 small (about 0.30 mm.) to medium-sized (0.3-0.35 mm.). with flattened dorsal and high ventral sides. narrow. oblong: a) coefficient of elongation about 1.4; b) co-efficient of broadening about 1. Structure of initial part of test globigerinoid, low-trochoid. Number of chambers in initial part of test 4-5. 3.5 chambers in the last whorl. Chambers increase rapidly in size. The last chamber, strongly extended lengthwise, is the largest. Relationships of dimensions of individual elements of the last whorl : a) width of penultimate to that of last chamber 0.8-0.9; b) length of base of last chamber to its width 1-1.2. Height of last chamber greater than height of preceding part of test. Last chamber elonga- ted-oval. First chamber of last whorl round, next-to-last chamber subquadrate, perpendicular to the last chamber. Side of last chamber oval, subquadrate. Surface of chambers flattened-inflated. Chamber arrangement compact. Inter- cameral sutures thin. not deep, straight. Outer margin slightly undulate. Umbilical depression narrow to broad. Aperture marginal, horizontal, open, slitlike, extends from the center of the test to the beginning of the outer margin; located below the overhanging. slightly curved margin of the last chamber. Perforation frequent, coarse.

Variation. - In this species the shape of the last chamber is variable, in some specimens it stretches considerably along its width (tf. 5, figs. 5, 6). The width of the umbilical depression changes (tf. 5, figs. 7, 8 - umbilicus is broad. 5. 6, umbilicus is narrow).

Comparison. - This species differs from Globigerina compressaeformis Khalilov (Shutskaya, 1970, table 4) by: 1) its smaller test size; 2) the oblong shape of the test, broadness coefficient I ; 3) the different dimen- sional relationships of the individual elements of the last whorl: the ratio of the widths of the penultimate and last chambers being less than one, at which point the maximum width of the coil is in the area of the last chamber.

This taxon was a junior homonym of Globigerina elongata d'Orbigny 1826

References:

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

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina elongata Shutskaya 1970

Globigerina elongata Shutskaya

References:

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