The smalleye hammerhead (Sphyrna tudes), also called the golden hammerhead or curry shark, is a small species of hammerhead shark in the family Sphyrnidae. This species was historically common in the shallow coastal waters of the western Atlantic Ocean, from Venezuela to Uruguay. It favors muddy habitats with poor visibility, reflected by its relatively small eyes. Adult males and juveniles are schooling and generally found apart from the solitary adult females. Typically reaching in length, this shark has a unique, bright golden color on its head, sides, and fins, which was only scientifically documented in the 1980s. As in all hammerheads, its head is flattened and laterally expanded into a hammer-shaped structure called the cephalofoil, which in this species is wide and long with an arched front margin bearing central and lateral indentations. The yellow-orange pigments of the smalleye hammerhead seem to have been acquired from the penaeid shrimp Xiphopenaeus kroyeri, the main food of juvenile sharks, and from sea catfish and their eggs, the main food of adults. The golden color may serve to conceal it from predators such as larger sharks. This species is viviparous, with the developing embryos sustained by a placental connection formed from the depleted yolk sac. Females bear litters of five to 19 pups every year following a gestation period of 10 months. Reproductive seasonality, litter size, and size at maturity vary between geographical regions. Because of its abundance, the smalleye hammerhead is an economically important bycatch of artisanal gillnet fisheries throughout its range, and is used as food. In recent years, overfishing has caused marked declines in its numbers off Trinidad, northern Brazil, and probably elsewhere. Coupled with the smalleye hammerhead's low reproductive rate, this led the International Union for Conservation of Nature to list the smalleye hammerhead as critically endangered in 2020. Taxonomy and phylogeny Despite being one of the most easily recognizable sharks, the smalleye hammerhead has had a long history of taxonomic confusion that still remains to be fully resolved. Its scientific name originated in 1822, with French zoologist Achille Valenciennes' description of Zygaena tudes in the scientific journal Mémoires du Muséum National d'Histoire Naturelle; the specific epithet tudes is Latin for "hammer". Valenciennes made reference to three specimens, one from Nice in France, one from Cayenne in French Guiana, and one from the Coromandel Coast of India. For over two centuries, though, taxonomists believed Valenciennes' account matched the great