Proceedings of the California Academy of Natural Sciences. In April 1855, French biologist Charles Frédéric Girard published another description of this species, naming it Triakis semifasciata. Despite M. felis being the senior synonym, an error in recording the dates of publication resulted in the widespread use of T. semifasciata as the leopard shark's scientific name. As a result of this long-standing error, Triakis semifasciata came to be recognized as the valid name (as a nomen protectum) and Mustelis felis was invalidated (as a nomen oblitum). The specific epithet semifasciata comes from the Latin words semi ("half") and fasciatus ("banded"), describing this shark's dorsal pattern of saddle-like markings. In older literature, this species may be referred to as "tiger shark" or "catshark". The genus Triakis contains two subgenera, Triakis and Cazon. The leopard shark is placed within the subgenus Triakis along with the banded houndshark (T. (Triakis) scyllium). A 2006 phylogenetic analysis by J. Andrés López and colleagues, based on protein-coding genes, revealed that Triakis and Cazon are in fact not closely related, and additionally that the leopard shark may be the most basal member of its family. Distribution and habitat The leopard shark occurs in the Northeastern Pacific Ocean, from the temperate continental waters of Coos Bay, Oregon to the tropical waters of Mazatlán, Mexico, including the Gulf of California. It favors muddy or sandy flats within enclosed bays and estuaries, and may also be encountered near kelp beds and rocky reefs, or along the open coast. Numbers have been known to gather near discharges of warm effluent from power plants. Leopard sharks generally swim close to the bottom and are most abundant from the intertidal zone to a depth of , though they may be found as deep as . Many leopard sharks, particularly in the north, leave their coastal habitats in winter and return in early spring. A study in Tomales Bay in northern California determined that they depart when the water temperature drops below 10–12 °C (50–54 °F); one tagged shark was found to have swum some south. While a few leopard sharks have been documented traveling hundreds of kilometers, most individuals tend to remain in a localized area for much of their lives. This low level of dispersal has led to genetic divergence across its range. Seven discrete gene pools have been identified along the Californian coast between Humboldt Bay and San Diego. Of these, the