نتایج جستجو برای: trace fossil

تعداد نتایج: 91986  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2002
Mary L Droser Sören Jensen James G Gehling

The trace fossil record is important in determining the timing of the appearance of bilaterian animals. A conservative estimate puts this time at approximately equal 555 million years ago. The preservational potential of traces made close to the sediment-water interface is crucial to detecting early benthic activity. Our studies on earliest Cambrian sediments suggest that shallow tiers were pre...

2012
Roy E. Plotnick

—The potential of the ichnofossil record for exploring the evolution of behavior has never been fully realized. Some of this is due to the nature of the trace fossil record itself. Equally responsible is the separation of ichnology from the relevant areas of modern behavioral biology. The two disciplines have virtually no concepts, methods, or literature in common. The study of animal behavior ...

Journal: :Proceedings. Biological sciences 2008
Graham N Stone Raymond W J M van der Ham Jan G Brewer

Trace fossils of insect feeding have contributed substantially to our understanding of the evolution of insect-plant interactions. The most complex phenotypes of herbivory are galls, whose diagnostic morphologies often allow the identification of the gall inducer. Although fossil insect-induced galls over 300Myr old are known, most are two-dimensional impressions lacking adequate morphological ...

2016
Adiël A. Klompmaker Roger W. Portell Sancia E.T. van der Meij

Members of the Cryptochiridae are small, fragile, symbiotic crabs that live in domiciles in modern corals. Despite their worldwide occurrence with over 50 species known today, their fossil record is unknown. We provide the first unambiguous evidence of cryptochirids in the fossil record through their crescentic pits, typical for certain cryptochirids, in Western Atlantic fossil corals, while th...

2008
Matthew J. Kohn

Many fossils are assumed to take up trace elements by a process of combined diffusion plus adsorption (DA), yet in principle composition profiles can be explained by several different diffusion-limited processes, including diffusion plus reaction or recrystallization (DR) and double-medium diffusion (DMD). The DA and DMD models are supported by REE and U composition profiles across fossil teeth...

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