CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinoides subconglobatus var. subconglobata Shutskaya 1958

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.


Higher levels: pf_cat -> G -> Globigerinoides -> Globigerinoides subconglobatus subconglobata
Other pages this level: << < G. ruber parkeri, G. rubra seigliei, G. rubriformis, G. sacculifer brachysacculifer, G. sacculifer minimus, G. sacculifer spinulosus, G. sacculifera subsacculifera, G. sacculiferoides, G. sacculiferus immatura, G. sacculiferus irregularis, G. semiinvoluta, G. semiinvolutus, G. sicanus, G. sicanus praesicanus, G. subconglobatus micra, G. subconglobatus subconglobata, G. subquadrata, G. subquadratus praesubquadratus, G. subquadratus subelongatus, G. suleki, G. tapiesi, G. tenella, G. transitoria, G. triloba altiapertura, G. triloba aspera, G. trilobus bullatus, G. tyrrhenicus

Globigerinoides subconglobatus subconglobata

Citation: Globigerinoides subconglobatus var. subconglobata Shutskaya 1958
Rank: Variety
Type locality: Not designated.
Type age (chronostrat): Upper Eocene
Type sample (& lithostrat): Kerestinskiy horizon, underlying the Kuma Series
Type specimens: pl.I, figs.4-11
Type repository: Probably in the Collection of the Geological Institute of the Russian Academy of Sciences
Described on page(s) : 86

Current identification/main database link: Globigerinatheka subconglobata Shutskaya 1958


Original Description
[Translation from the Russian] - Test nearly spherical, formed by three spiral whorls, of which the first two make up a small portion of the test, the last whorl formed by three large, weakly inflated chambers tightly adhering to one another. The final chamber is usually smaller than the preceding one. Sutures weakly depressed. There are several apertures; on the dorsal side, they are in the form of small openings at the junctions of the chambers; on the ventral side there are usually two slitlike or arcuate openings at the base of the final chamber. The apertures are never gaping, even in the largest specimens. Wall coarsely perforate.

Раковина почти сферическая, образована тремя оборотами спирали, из которых два первых составляют незначительную часть раковины, а в последнем насчитываются три крупные, плотно примыкающие одна к дру­гой слабо выпуклые камеры. Последняя камера обычно меньше преды­дущей. Швы слабо углубленные. Устьев несколько: на спинной стороне в виде небольших отверстий в местах сочленения камер, на брюшной сто­роне их обычно два, щелевидных или аркообразных, расположенных у ос­нования последней камеры. Даже у самых крупных экземпляров они не бывают зияющими (табл. I, фиг. 10). Стенка грубопористая.

Size: Dimensions: Average diameter ca. 0.50 mm, ca. 0.65 mm in large specimens.

Extra details from original publication
Variability and comparison - Like Globigerinoides subconglobatus micra Shutskaya, the described species contains specimens deviating from the regular spherical form, however, this feature has no bearing on the definition of the species. The basic specific characteristics, the weakly depressed sutures and the weakly inflated chambers, are persistent in all the several hundred specimens in our collection. The shape and the size of the apertures on the ventral side is more variable; they are slitlike in some specimens, and arcuate in others.

The present species is closest to Globigerinoides conglobatus (Brady) from the Upper Eocene, Beloglinskiy horizon, from which it differs in some basic specific features.

[p. 88, under Globigerinoides conglobatus (Brady)]: The sharply depressed sutures and the strongly inflated chambers characterize this species and allow one to readily distinguish it from Globigerinoides subconglobatus [Shutskaya]. Among the more variable yet distinctive features of the species are the "secondary diagnostic characteristics," the shapes of the apertures and of the test. In some specimens, the aperture is almost slitlike, which makes it close to Globigerinoides subconglobatus; in some others, the aperture is widely open, gaping, never present in Globigerinoides subconglobatus. In the shape fo the test, individual specimens resemble Globigerina, which is not the case with Globigerina subconglobatus.

Этот вид ближе всего стоит к G. conglobatus Brady из белоглинского горизонта верхов верхнего эоцена, отличаясь от него некоторыми основ­ными видовыми признаками, что будет разобрано при описании послед­него вида.

Распространение. Широко встречается в керестинском горизон­те, нижнем горизонте верхнего эоцена, залегающем непосредственно под кумским (слои с Lyrolepis caucasica Roman.) Северного Кавказа, Крыма, Южных Ергеней и Северо-Западного Прикаспия. Этот вариетет постоян­но встречается в керестинском горизонте всех изученных разрезов ука­занных регионов, но распределен в каждом разрезе далеко не равномерно. В одних прослоях обнаруживаются его массовые скопления, в других — отдельные экземпляры, в третьих — полное отсутствие.

Editors' Notes
As notd in the Ellis & Messina catalog Shutskaya cited the species as Globigerinoides subconglobatus Chalilov var. subconglobata Chalilov (msc.). However, since Shutskaya (1958) provided the first published description the correct attribution is to that pulbication.

A holotype was not deisgnated but Bolli (1972) designated as lectotopye the specimen of fig 8.

References:

Bolli, H. M. (1972a). Correlation de las estaciones JOIDES 29, 30 y 31 del Caribe con Jamaica, Venezuela y Trinidad. . 3(5): 1315-1336. gs

Shutskaya, E. K. (1958). Variability in some lower Paleogene planktonic foraminifera from the northern Caucasus. Voprosyi Mikropaleontologii. 2: 86-. gs


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Globigerinoides subconglobatus subconglobata compiled by the pforams@mikrotax project team viewed: 22-10-2020

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