designated C. mantelli as the type species, but he abruptly replaced the position with another taxon identified as 'Isurus denticulatus' without explanation in a 1964 paper, a move now rejected as an invalid taxonomic amendment. This nevertheless led Russian paleontologist Viktor Zhelezko to erroneously invalidate the genus Cretoxyrhina in a 2000 paper by synonymizing 'Isurus denticulatus' (and thus the genus Cretoxyrhina as a whole) with another taxon identified as 'Pseudoisurus tomosus'''. Zhelezko also described a new species congeneric with C. mantelli based on tooth material from Kazakhstan, which he identified as Pseudoisurus vraconensis accordingly to his taxonomic reassessment. A 2013 study led by Western Australian Museum curator and paleontologist Mikael Siverson corrected the taxonomic error, reinstating the genus Cretoxyrhina and moving 'P'. vraconensis into it. In 2010, British and Canadian paleontologists Charlie Underwood and Stephen Cumbaa described Telodontaspis agassizensis from teeth found in Lake Agassiz in Manitoba that were previously identified as juvenile Cretoxyrhina teeth. This species was reaffirmed into the genus Cretoxyrhina by a 2013 study led by American paleontologist Michael Newbrey using additional fossil material of the same species found in Western Australia. Between 1997 and 2008, paleontologist Kenshu Shimada published a series of papers where he analyzed the skeletons of C. mantelli including those found by the Sternbergs using modernized techniques to extensively research the possible biology of Cretoxyrhina. Some of his works include the development of more accurate dental, morphological, physiological, and paleoecological reconstructions, ontogenetic studies, and morphological-variable based phylogenetic studies on Cretoxyrhina. Shimada's research on Cretoxyrhina helped shed new light on the understandings of the shark and, through his new methods, other extinct animals. EtymologyCretoxyrhina is a portmanteau of the word creto (short for Cretaceous) prefixed to the genus Oxyrhina, which is derived from the Ancient Greek ὀξύς (oxús, "sharp") and ῥίς (rhís, "nose"). When put together they mean "Cretaceous sharp-nose", although Cretoxyrhina is believed to have had a rather blunt snout. The type species name mantelli translates to "from Mantell", which Louis Agassiz named in honor of English paleontologist Gideon Mantell for supplying him the syntypes of the species. The species name denticulata is derived from the Latin word denticulus (small tooth) and suffix āta (possession of), together meaning "having small teeth". This is a reference to the appearance of lateral cusplets in most of the teeth in C. denticulata. The species vraconensis derived from the word vracon and the Latin ensis (from), meaning