C. maximus (GUNNERUS, 1765), Extant Basking Shark

This huge shark, (to 10 with reports to 15 meters) is second only to the whale shark in size. It is characterized by its large mouth with numerous (200 files per jaw) small, similarly shaped, hook-like teeth and extremely enlarged gill openings, which incorporate unique gill rakers. These plankton-capturing devices are hair-like (mucous) denticles, which are periodically shed and when found, help confirm the presence of this genus in the fossil record. C. maximus is a migratory species of temperate & boreal, coastal & off-shore waters.

Fossil Basking Sharks

According to Cappetta (1987), a single extinct (Oligocene-Miocene) species has been described, C. parvus LERICHE 1908, and that specimens from the Pliocene and later should be attributed to C. maximus. He describes the teeth of C. parvus as being unlike those of the extant species and more reminiscent of Alopias exigua (PROBST 1879) with branching roots. Cione & Reguero (1998) reported a Cetorhinus gill raker from the La Meseta Formation (Middle Eocene) of Seymour Island (Antarctica). In this paper, they summarized the various reports of this taxa from the fossil record: Eocene - North America (dubious), Oligocene - Europe, Miocene - Europe, No America & Japan and Pliocene of Europe & Chile. Purdy et al. (2001) report Cetorhinus sp from the Pungo River (unit 3) of Lee Creek.

Below illustrates Cetorhinus teeth and gill raker. The teeth are from Sharktooth Hill (Kern County, California) and conform well to Cappetta's illustration and description of a C. maximus tooth. The roots are robust but worn, weakly revealing the presence of two lobes. Cappetta suggests that the nutrient groove is narrow and significantly deeper in unworn teeth. A cutting edge is present, does not extend to the apex of the crown and is irregular near the root where the cusp appears "pinched".

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