A primitive fish provides key characters bearing on deep osteichthyan phylogeny

Ray-finned bony fish (ranging from cod to guppies) and lobe-finned bony fish (lungfish, coelacanths and the ancestors of the land vertebrates) were clearly once close relatives, but a large morphological gulf still separates fossils of both groups dating from times when they looked much more similar than they do now. A fossil of a primitive lobe-finned fish that combines many features found in both groups has now been discovered in the Yumman fossil beds in China, and this new species offers a bridgehead between the two distinct lines of fishy descent.