Catalog - Globigerina subtarchanensis

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Globigerina subtarchanensis

Citation: Globigerina subtarchanensis Agalarova & Pronina 1975

Type specimens: pl. [tf.] 3a-c, holotype, X 72. : holotype (tf. 3a-c), no. 389.

Type sample (& lithostrat): lower, salt-bearing series.

Type age (chronostrat): Upper Miocene, middie Sarmatian

Type locality: By the city of Duzdag, Nakhichevan ASSR, Azerbaidzhan SSR.

Type repository: Baku; microfauna collection of the Institute of Geology, Academy of Sciences of the Azerbaidzhan SSR, Baku, USSR;

[Translation from the Russian. - Diagnosis. Test oval, lowly trochoid: peripheral margin lobate. On the dorsal side are 2.5 whorls, in each of them are five spheroidal chambers, on the ventral side around the umbilicus there arc five pear-shaped chambers. Septal sutures depressed, aperture semilunatc with a lip.
[Descliption. - Test small, chambers inflated, arranged along the coils of a clearly expressed lowly trochoid spiral: peripheral margin broadly rounded, lobate. On the flat side 2.5 whorls of the spire arc visible, in each of them there are five spheroidal, compactly adjacent chambers: the last two chambers of the last whorl in size comprise almost half of the test. Chambers of the inner whorls form an almost flat surface or slightly protrude above the later whorl of the spiral. On the ventral side, there are disposed around the deep umbilicus five pear-shaped chambers, broadly rounded toward the peripheral margin of the test. Apertural chamber perpendicular to the three other chambers. Septal sutures narrow, depressed, on the ventral sid e radial, deep. Aperture in the form of a semilunate aperture, located in the last chamber, open on the umbilical side and equipped with a lip. Wall calcareous, vitreous, surface covered with the depressions of the foramina.

Dimensions. - Greatest diameter 0.21 mm., least diameter 0.58 [sic; 0.18?] mm., thickness 0.13 mm.

(Comparative remarks. - The form described is close to G!obigerina larchanensis Subbotina and Chutskaya, encountered in large batches in the deposits of the Tarkhan Horizon of the Northern Caucasus, and in a restricted quantity in the Dzhebrail region and the Nakhichevan ASSR, differs by the flattened and less trochoid dorsal side, fewer number of chambers and of whorls in the spire, and by the radial and compactly arranged chambers of the ventral side. Our species is in external appearance similar to Globigerina pseudoedita Subbotina, described from the deposits of the Solotvin suite of the Helvetian of the Transcarpathians, but differs by the strictly radial arrangement of the chambers on the ventral side and by the presence of the apertural cover-plate.]

References:

Agalarova, D. A. & Pronina, M. T. (1975). Novye vidy Globigerina iz miotsenovykh otlozheniy Nakhchevanskoy ASSR. Izvestiya Akademii Nauk Azerbaidzhanskoy SSR. 2: 20-25. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina subtarchanensis Agalarova & Pronina 1975

Globigerina subtarchanensis

References:

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