Size reduction and ornamental oscillation within a Barremian lineage of giant heteromorphic ammonites (Early Cretaceous, northwestern Tethyan margin)
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چکیده
منابع مشابه
Late Barremian-Early Aptian Ammonites from the Tirgan Formation, Kopet-Dagh Sedimentary Basin, NE Iran
During the recent field research on the Tirgan Formation in the west of Kopet-Dagh sedimentary basin, ammonite assemblages were obtained from the carbonate strata of this formation. This new finding is important for stratigraphical purpose. In this research, 3 genera belong to Heteroceras, Deshayesites and Cheloniceras? as well as one uncertain genus belongs to Turkmeniceras are determined. The...
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In cultivated tomato plants which were largely but not exclusively derived from triploids, chromosomes of two distinct sizes were found associated with the nucleolus in the pollen mother cells. Since a trivalent was found on the nucleolus in the simple trisomic type, triplo-A only, evidently it is the A or first chromosome which is dimorphic. At somatic metaphase this chromosome has a distinct ...
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ژورنال
عنوان ژورنال: Cretaceous Research
سال: 2018
ISSN: 0195-6671
DOI: 10.1016/j.cretres.2017.02.001