Shark-tooth weapons from the Republic of Kiribati in the Pacific Ocean point to the existence of two shark species that may have disappeared from the area long before scientists knew they existed, researchers say. People from the Gilbert Islands, which make up much of Kiribati, had been making weapons using the teeth of dusky and spotfin sharks until 130 years ago. Today, the two species can be spotted elsewhere: spotfin sharks near Australia and Indonesia, and dusky sharks near Fiji. "We're losing species before we even know that they existed," said study researcher Joshua Drew. "That just resonates with me as fundamentally tragic."