Paleocarcharodon orientalis crenulations

P. orientalis tooth with crenulations. Morocco.

Palaeocarcharodon orientalis is arguably the most sought after Paleogene shark tooth in eastern North America. The striking similarity of these teeth, with those of the extant Great white undoubtedly feeds this collecting priority. Compared with Otodus (and most other sharks), this species' distribution is very limited in both time and space. This genus also serves as a flash-point in the Great white evolution debate. One viewpoint, as argued by Bob Purdy (1996), traces the lineage Palaeocarcharodon - Carcharodon auriculatus - Carcharodon megalodon - Carcharodon carcharias. The alternate scenario contends that Otodus evolved from Cretalamna, and terminated with Carcharocles megalodon (the modern Great white having nothing to do with either Palaeocarcharodon or C. megalodon). In addition to rarity and importance, these teeth have another important feature — they are aesthetically very pleasing, and hence, very popular among fossil collectors.

Even if the stratigraphic position is unknown, it would be difficult not to recognize Palaeocarcharodon teeth. Labio-lingually compressed triangular teeth with coarse & irregular serrations and usually combined with serrate lateral cusplets is not a common tooth-design. In the western Atlantic, these are medium-sized teeth, usually less than 3 cm. Moroccan specimens exceed 5 cm with reports of them reaching the 6 cm range. The dentition is of a cutting-design and has a delicate quality when compared with those of Otodus.

Palaeocarcharodon orientalis (SINZOW, 1899) is currently thought to be the only valid member of this genus. Cappetta (1987) ascribed them to the Paleocene of North & Western Africa and the Soviet Union. Case (1989, 1993) reported them from the Paleocene of Maryland & New Jersey (USA) and Purdy (1998) from the Williamsburg Formation (Thanetian - Late Paleocene) of South Carolina.. Their abrupt appearance and disappearance remains a mystery.

Also mysterious is the presence of two Palaeocarcharodon specimens in the Demopolis Formation (early Late Campanian) of Mississippi. The time jump between these sediments and the normal occurrence suggests they were transported to this earlier horizon. So far lacking are other Paleocene specimens to validate the contamination hypothesis. However, the severe root erosion on these Frankstown orientalis teeth may explain why contemporary teeth are not found -- rootless teeth could be easily overlooked (Striatolamia as Scapanorhynchus, sand tigers as their Cretaceous counterparts, Hypolophus as Pseudohypolophus, Brachycarcharias lerichi as Serratolamna serrata, etc.).