General evolutionary trends in Orbitolinas
Schroeder, R. (1975). General evolutionary trends in Orbitolinas. Rev. Esp. Micropaleontol. Numero Especial: 117-128
In: Revista Española de Micropaleontología. ITGE: Madrid. ISSN 0556-655X, more
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| Keywords |
Orbitolina (Conicorbitolina) Schroeder, 1973 † [WoRMS]; Orbitolina (Mesorbitolina) Schroeder, 1962 † [WoRMS]; Orbitolina (Orbitolina) d'Orbigny, 1850 † [WoRMS]; Palorbitolina Schroeder, 1963 † [WoRMS]; Praeorbitolina Schroeder, 1964 † [WoRMS]
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| Abstract |
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: 0. (Mesorbitolina) Schroeder 1962, 0 . (Orbitolina) D’Orbigny 1850 and 0. (Conicorbitolina) Schroeder 1973. A review about the evolution of these three lineages is given. |
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