Catalog - Globigerina rotundaenana

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina rotundaenana Shutskaya 1970

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 -> Globigerina -> Globigerina rotundaenana
Other pages this level: << < G. quadrilatera, G. quadrilobata, G. quadritriloculinoides, G. quinqueloba, G. quinqueloba egelida, G. radians, G. regina, G. regularis, G. reticulata, G. ridenda, G. riveroae, G. roblesae, G. rohri, G. rosacea, G. rosetta, G. rotundaenana, G. rotundata, G. rotundata jacksonensis, G. rubescens, G. rubra, G. rudis, G. rugosa, G. rustica, G. sabina, G. sacculifera, G. sakitoensis, G. sallentina, G. santamariaensis, G. sastrii, G. scabrosa, G. scalena> >>

Globigerina rotundaenana

Citation: Globigerina rotundaenana Shutskaya 1970
Rank: Species
Type sample (& lithostrat): lower part of the Middle Danat Subsuite
Type age (chronostrat): Lower Eocene, Bakchisarayan Stage, Globorotalia aequa Zone
Type locality: Malyy Balkhan Mts., westem Turkmenia, USSR
Type repository: Moscow; All-Union Scientific-Research Geological-Prospecting Petroleum Institute (VNIGNI), Moscow (probably)

Current identification/main database link: Subbotina roesnaesensis Olsson & Berggren, in Olsson et al. 2006


Original Description

Translation from the Russian. - Test small (about 0.3 mm.) high, subquadrate, coefficient of elongation 1-1.1, coefficient of broadening 1-1.1. Structure of initial part of test rotaloid, low-trochoid. Number of chambers of initial part of test 7-8. In the last whorl there are 3 chambers, but on the ventral side at the outer margin between the fust and last chambers the last chamber of the preceding whorl shows. Chambers increase in size rapidly. Ratio of dimensions of individual elements of the last whorl: a) ratio of width of penultimate chamber to width of last chamber 1-1.2; b) ratio of length of base of last chamber to its width 1.2-1.4, last chamber narrow, strongly elongated. Height of last chamber exceeds height of preceding part of test. Chambers of last whorl: first chamber round in outline, second and last ones subquadrate, with rounded inner margins and broadly rounded outer margin. Lateral surface of last chamber oval in outline. Surface of chambers flattened-inflated. Arrangement of chambers in last whorl entirely compact. Intercameral sutures thin, not too deep. Outer margin rough, weakly undulate. Umbilical depression narrow or absent. Aperture is a slightly opened, curved slit extending from the center of the test to the beginning of the outer margin. Test wall covered with frequent large pores.

Size:

Etymology:

Extra details from original publication
Variation. - In test shape this species stands at the boundary of the transition from subquadrate (tf. 3, figs. 11, 13) to rounded (tf. 3, figs. 12, 14, 15, 16).

Comparison. - This species differs from Globigerina nana Khalilov by: 1) the broad initial part of the spiral in the last whorl, making the last chamber narrower than the preceding one - ratio of widths of penultimate to last chambers 1.0-1.2; 2) the subquadrate shape of the test, which is close to rounded.

The compact chamber arrangement and coarse perforation of the test wall characteristic of this species, together with the size relation between chambers typical for the species, are observed in specimens referred by Loeblich and Tappan (1957, loc. cit.) to Globigerina triloculinoides.

Editors' Notes

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


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Globigerina rotundaenana compiled by the pforams@mikrotax project team viewed: 30-9-2022

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