Although researchers in the late 1990s and early 2000s, including Bennett and Jouve, suggested that all these species probably represented growth stages on just one kind of "Ctenochasma", in a more comprehensive 2007 study, Bennett demonstrated that three distinct species could be recognized based on the number and slenderness of the teeth, which varied across all growth stages. "C. roemeri", the earliest species, is characterized by its relatively low number of only moderately slender teeth. The later "C. taqueti" had a moderate number of slender teeth, and the last species, "C. elegans", had a high number of very slender teeth. These three species, arranged chronologically, probably represent a single evolutionary lineage in which the filter-feeding apparatus was gradually refined.