The Port Jackson shark (Heterodontus portusjacksoni) is a type of bullhead shark of the family Heterodontidae that lives in southern Australia. It has a large head with ridges above the eyes and a pattern of dark markings on its body. It lays eggs in shallow water and feeds on sea urchins, mollusks, and fish. It can grow up to 1.65 meters long. It is named after Port Jackson, the natural harbor of Sydney, where it is commonly found. It has two spines in front of its dorsal fins that can be used for defense or to anchor itself in crevices.