Notorynchus

Notorynchus is a genus of Seven-gill shark that evolved in the Late Cretaceous through the Present Day. The Sevengill shark is a large (to 3m, possibly reaching 4) shark which according to Compagno (1984 & 2005) inhabits shallow (1-135m), temperate coastal continental waters. They are found in isolated regions worldwide; however, they are no longer present in the Western North Atlantic.

== Fossil Record == Known from isolated teeth only, Cappetta (1987:48) similarly defines the genus and noted that the conule count may vary between 4-7 and that these teeth are less mesio-distally elongated relative to Hexanchus. He included three representative species:
 * N. aptiensis (PICTET 1865) Upper Aptian (Lower Cretaceous) Southern France
 * N. primigenius (AGGASSIZ 1834b) Oligocene-Miocene of North America, Europe, and Australia
 * N. serratissimus (AGASSIZ 1843b) Ypresian, England

Two additional species as present in the Chesapeake region:
 * N. serratissimus - Aquia Formation(Paleocene), and Nanjemoy Formation(Ypresian)
 * M. primigenius - Old Church Formations(Oligocene), Calvert Formation, Choptank Formation, and Eastover Formation (Miocene)

== Morphologies == === Sharktooth Hill ===

Unlike Lee Creek where Notorynchus teeth are common and Hexanchus scarce, in the Round Mountain Silt at Sharktooth Hill, the former is rare and the latter relatively common. This specimen likely represents N. cepedianus.