General Evolutionary Trends in Orbitolinas
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Rolf Schroeder [1]
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[1] Goethe University Frankfurt
Goethe University Frankfurt
Frankfurt, Alemania
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- Localización: Revista española de micropaleontología, ISSN 0556-655X, Nº. Extra 0, 1975, págs. 117-128
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
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Resumen
After a short survey about the most important structural elements of Orbitolinas the author discusses at first the origin of this foraminiferal group. The first true Orbitolinas have developed from Praeorbitolina SCHROEDER 1964 at the boundary Lower Aptian/Upper Aptian. Palorbitolina SCHROEDER 1963 (containing «Orbitolina» lenticularis) does not belong to the true Orbitolinas.
Within the genus Orbitolina, at present, one can differentiate between three general evolution lines, which I have given the status of subgenera: O. (Mesorbitolina) SCHROEDER 1962, O. (Orbitolina) D'ORBIGNY 1850 and O. (Conicorbitolina) SCHROEDER 1973. A review about the evolution of these three lineages is given.
