Citation: Globigerina schachdagica Khalilov 1956Rank: speciesType specimens: pl. 1, fig. 3a-c, holotype, X 6o.: ; no. 260. Type age (chronostrat): Lower Paleocene, Danian. Type locality: The northeast part of the Azerbaidzhan S.S.R. Type repository: Baku; Geological Institute, Academy of Sciences, Baku, Azerbaijan
Original Description Translation from the Russian. - Test rounded, with a lobate periphery. There are two whorls, each with six rapidly enlarging spherical chambers, subsequently becoming elongate. Ventrally, there are six pear-shaped chambers, of which the last ones are ovalelongate at the periphery. Test low conical, rounded, with a broad lobate periphery. The chambers increase rapidly in size until the last or the penultimate one. Viewed from the periphery, a sharp enlargement of one of the last two chambers is seen. Dorsally, the initial part of the test is indistinct. Following the initial portion there are six chambers in the first whorl, sharply increasing in size; in the second whorl there are six inflated chambers, which sharply increase in size. Ventrally, six elongate pear-shaped chambers are radially arranged around the well-expressed umbilicus. Sutures between the chambers narrow, weakly arcuate, straight and deep, and weakly depressed only iu the first whorl. Aperture a small, semilunate, opening in the final chamber. Umbilical area broad, depressed. Wall calcareous, punctate. Size: Diameter 0.50 mm.; thickness 0.30 mm. Extra details from original publication Comparison. - The most variable feature of the new species is the size of the final chamber, which, however, retains its oval-elongate shape. In typical specimens this chamber is very large, strongly protruding on the ventral surface. Specimens are also found in which the final chamber is relatively small; in such specimens, the penultimate chamber is the largest one, oval-elongate, strongly protruding on the surface. The present species differs from Globigerina inconstans Subbotina, from the Danian of the Northern Caucasus, in the presence of elongate and very large chambers, and in the pear-shaped chambers of the final whorl on the ventral side.
Khalilov, D. M. (1956). 0 pelagicheskoy faune foraminifer Paleogenovykh otlozheniy Azerbaydzhana [Pelagic Foraminifera of the Paleogene Deposits of the Azerbaizhan SSR]. Trudy Instituta Geologii, Akademiya Nauk Azerbaidzhanskoi SSR. 17: 234-255. gs
Globigerina schachdagica compiled by the pforams@mikrotax project teamviewed: 5-6-2023