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Showing results for tags 'xenobiont'.
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Does anyone know of any instances -- or suspected instances -- of organisms that are known only from associated fossils, i.e. organisms that left absolutely no trace (i.e. 'xenobiont'), but are detectable from various epibionts that were once attached? In the Pennsylvanian of Kansas City, there are thin limestone beds in the lower Wea Shale that contain an abundance of Crurithyris brachiopods and ammovertellid forams that range persistently at least for several tens of miles. From south Kansas City, MO: From Excelsior Springs, MO, approximately 30 miles to the north: The ammovertellids are the little white things, and the Crurithyris are the bluish bb-like shells. Normally, in other strata, these fossils are sparse or only locally present. I didn't think much of these beds until I read that both fossil types have been found as epibionts attached to calcareous algae (both) and echinoids (Crurithyris). (See http://palaios.geoscienceworld.org/content/18/4-5/435.abstract and PDF at http://www.kgs.ku.edu/Current/2005/sawin/sawinandwest.pdf (page 9) ). This made me wonder if there were some soft bodied organism (perhaps sea-grass-like algae) that were present in abundance but left no trace -- carbon films, impressions, root/holdfast impressions, etc -- but did leave behind a mess of formerly attached shells. I can imagine vast 'gardens' stretching over wide expanses of the shelf.