Researchers have now found weapons that were made from the teeth of a shark species previously unknown to science.

The sharks were living in the Gilbert Island reefs in the Central Pacific about 130 years ago. The Gilbert Islands are a major part of the Republic of Kiribati in the Pacific Ocean.

The weapons were made by people living in islands in the Central Pacific in the 19th century. Historic records show that the weapons made by the Gilbertese Islanders were a part of their cultural identity and that special customs were performed during the hunting of these sharks.

For the current study, a study team led by Joshua Drew from Columbia University examined a collection of 120 of these weapons from the Field Museum of Natural History. The weapons included clubs, daggers, lances, spears and swords.

The study analysis revealed that the weapons were made from the teeth of eight shark species; two of which - the Spot-tail (Carcharhinus sorrah) and the Dusky (C. obscurus) - have never been identified in the region.

The spot-tail shark can be found near Australia and Indonesia, and dusky sharks can be spotted near Fiji. However, both of these aren't present in Kiribati now, reports LiveScience.

Researchers speculate that either the shark species live undiscovered near the islands or that they have gone extinct.

"We're losing species before we even know that they existed. That just resonates with me as fundamentally tragic," said Joshua Drew, an ichthyologist at Columbia University, reports LiveScience.

Researchers said that sharks in the reefs play an important role in maintaining the ecological balance, and that understanding the cultural and ecological heritage is the first step in planning conservation strategies.

"When we looked we found this shadow biodiversity, hints and whispers of what these reefs used to be like. It's our hope that by understanding how reefs used to look we'll be able to come up with conservation strategies to return them to their former vivid splendor," Drew said in a news release.

The study is published in the journal PLOS One