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Species Globorotalia quetra Bolli 1957 | ||||||
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| Diagnosis / Definition: | ||||||
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Bolli (1957): Shape of test very low trochospiral, spiral side flat or slightly concave, umbilical side strongly convex, angular; equatorial periphery strongly lobate; axial periphery subacute to acute, a spiny peripheral keel is often present in the early chambers of the last whorl; ultimate and penultimate chambers acute or rounded. Wall calcareous, perforate, distinctly spinose. Chambers angular to subangular, inflated; about 12, arranged in 2 1/2 whorls, the 4-5 chambers of the last whorl increasing rapidly in size. Sutures on spiral side oblique or curved, depressed; on umbilical side radial, depressed. Umbilicus fairly narrow, deep, open. Aperture a low arch; interiomarginal, extraumbilical umbilical. Coiling over 90 percent dextral in the Globorotalia formosa formosa and Globorotalia aragonensis zones. Largest diameter of holotype 0.64 mm. Largest diameter of figured paratype 0.50 mm. |
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| Discussion / Comments: | ||||||
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Bolli (1957): Globorotalia quetra Bolli, new species, is a very characteristic form in the upper Lizard Springs, where it is especially abundant in the Globorotalia formosa formosa zone. By its shape it might readily be mistaken for the middle Eocene Truncorotaloides rohri var. mayoensis Bronnimann and Bermudez or for G. topilenis Cushman (which probably is a Truncorotaloides). However, G. quetra lacks the sutural apertures on the spiral side which are characteristic for Truncorotaloides while its stratigraphic range is restricted to the lower Eocene. G. quetra appears to be closely related to G. wilcoxensis Cushman and Ponton, from which it is distinguished by the distinct angular shape of its test. Intermediate forms were found in the Globorotalia rex zone. |
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| Synonym list: | ||||||
| Bolli (1957): 1957 Globorotalia quetra Bolli. - Bolli : pl. 19, figs. 1-6 new species
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| Was used in synonym list of: | ||||||
| References: | ||||||
Bolli,H.M. (1957): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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