Maisey, John G.2005-10-062005-10-061981http://hdl.handle.net/2246/353722 p. : ill. ; 26 cm.Includes bibliographical references (p. 21-22)."Ctenacanthus Agassiz is a genus of elasmobranch, originally recognized by its dorsal finspines but now known from more complete remains. However, many other fossils, including isolated spines and complete fish, have been included in Ctenacanthus, although the spines differ from those of the type species, C. major, and from other presumably related species. Earlier diagnoses of Ctenacanthus are critically reviewed and the significance of previous diagnostic changes is discussed. It is concluded that Ctenacanthus sensu lato is paraphyletic. Some spines previously assigned to this taxon resemble living elasmobranch finspines, whereas others resemble hybodontid finspines. The fish described by Dean as Ctenacanthus clarkii should be referred to C. compressus. Both C. clarkii and C. compressus finspines are sufficiently like those of C. major for these species to remain within the genus. Ctenacanthus compressus is the only articulated Paleozoic shark so far described which can be assigned to Ctenacanthus. Ctenacanthus costellatus finspines are not like those of C. major, but instead resemble Sphenacanthus spines. Goodrichthys eskdalensis may be closely related to Ctenacanthus"--P. [1].10768488 bytesapplication/pdfen-USQL1 .A436 no.2718, 1981Ctenacanthus.Chondrichthyes, Fossil.Fishes, Fossil.Paleontology -- Paleozoic.text