I don’t know how I missed this yesterday. National Geographic
has an article on an interesting fossil, dating to about 290 MYA
(basically, the beginning of the Permian) , that provides some
interesting information on food chains. The fossilized amphibian
is also in exactly the right position to suggest it had been
eaten–it was lying tail-first along the shark’s digestive tract,
according to Kriwet. “Also, the fish remains are fully enclosed
within the amphibian’s outer covering of scales,” he added. That
confirms that it was indeed eaten by the amphibian and not the
shark. Before the shark ate it, the amphibian had caught a young
fish known as an acanthodian, which was covered in bony spines.
“The fish was swallowed side on, otherwise the spines could have
got stuck in the amphibian’s mouth or throat,” Kriwet said. “The
fish is situated in quite the correct area of digestive tract of
the amphibian,” said said study co-author Ulriche Heidtke, a
paleontologist from the National History Museum of the
Palatinate