Carcharocles aksuaticus

Carcharocles aksuaticus occupies the morphospace between the smooth-crowned O. obliquus and the irregularly serrate C. auriculatus. The serrae vary (with stratigraphic time) between very fine crenulations on the basal half of the cutting edge of the principal cusp, to fine but irregular serrae over 75% of the crown. Teeth with very fine crenulations have been called ''Otodus obliquus var. mugodzharicus'' ZHELEZKO, 1999. Unfortunately the teeth of the type series of mugodzharicus vary between slightly serrate to fully serrate, so the two forms are probably synonymous with C. aksuaticus as the senior synonym. It could be possible to slip in an additional species into this transition, for the forms with just fine crenulations on the cutting edge, rather than discrete serrae. Whether these are regarded as serrated Otodus or the earliest Carcharocles is unimportant, a matter of (man-made) terminology.