Lungfish-fish equipped with rudimentary lungs in addition to their gills-occupy a side branch of fish evolution, reaching a peak of diversity during the late Devonian period, about 350 million years ago, and then dwindling in importance (today there are only a handful of lungfish species). Middle-Late Devonian (400-360 million years ago) Like many other fossil fish (not to mention aquatic reptiles like plesiosaurs and mosasaurs), Bonnerichthys thrived not in the deep ocean, but the relatively shallow Western Interior Sea that covered much of North America during the Cretaceous period.ĭipterus (Greek for "two wings") pronounced DIP-teh-russ What he found was a large (20 foot long) prehistoric fish that fed not on its fellow fish, but on plankton-the first filter-feeding bony fish to be identified from the Mesozoic Era.
Middle Cretaceous (100 million years ago)Īs so often happens in paleontology, the fossil of Bonnerichthys (preserved on a huge, unwieldy slab of rock extracted from a Kansas fossil site) had been stashed unnoticed for years until an enterprising researcher took a closer look at it and made an amazing discovery. Bonnerichthys (Greek for "Bonner's fish") pronounced BONN-er-ICK-thiss
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