منابع مشابه
The old and the new plankton: ecological replacement of associations of mollusc plankton and giant filter feeders after the Cretaceous?
Owing to their great diversity and abundance, ammonites and belemnites represented key elements in Mesozoic food webs. Because of their extreme ontogenetic size increase by up to three orders of magnitude, their position in the food webs likely changed during ontogeny. Here, we reconstruct the number of eggs laid by large adult females of these cephalopods and discuss developmental shifts in th...
متن کاملBite marks in Jurassic and Cretaceous ammonite s
Ammonites are among some of the best fossils to collect. They are relatively easy to find, for example, in the Lower Jurassic Posidonia Shale in Germany and the Jurassic sediments of Dorset in the south of England. The larger, wellpreserved ones will always be sought after and, if of sufficiently high quality, may even be displayed in museum exhibitions. However, while these nicely-preserved, c...
متن کاملTerminal Cretaceous Extinction
A number of mechanisms have been proposed for the massive extinction of biota at the Cretaceous-Tertiary transition some 65 million years ago. Most of them were reviewed recently (I). Two additional mechanisms have been proposed, however, since that review was compiled-the "greenhouse" mechanism (2) and the Arctic spillover model (3). In the first of these. McLean has proposed that the large la...
متن کاملupper cretaceous in iran
between the lower and upper cretaceous there were some diastrophic movements, belonging to the austrain phase. these movements, which can be traced in many parts of north and central iran, caused extensive precenomanian erosion. even in southwest iran a wide spread discontinuity is reported at the base of the kazhdumi formation, which is possibly related to these movements. in the kopet - dagh ...
متن کاملDeep-Time Phylogenetic Clustering of Extinctions in an Evolutionarily Dynamic Clade (Early Jurassic Ammonites)
Conservation biologists and palaeontologists are increasingly investigating the phylogenetic distribution of extinctions and its evolutionary consequences. However, the dearth of palaeontological studies on that subject and the lack of methodological consensus hamper our understanding of that major evolutionary phenomenon. Here we address this issue by (i) reviewing the approaches used to quant...
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ژورنال
عنوان ژورنال: Geological Magazine
سال: 1925
ISSN: 0016-7568,1469-5081
DOI: 10.1017/s0016756800105795