In 1862, a group of Spanish explorers set off on the “Comisión Científica del Pacífico,” the premiere mission for Spanish scientists studying the Americas in the 19th century. They returned three years later with a bevy of specimens and new knowledge of natural history. Some of those specimens, however, never made it into the scientific record. 

Plekocheilus cecepeus, a new snail species described in the journal ZooKeys, was one of 20 new species the Pacific expedition brought back from South America, but it remained hidden on the dusty shelves of Madrid’s National Museum of Natural Sciences for more than a century and a half. While researchers believe the snail was found in Ecuador, they can’t pinpoint its exact region of origin. 

Who knows what other exciting scientific discoveries might be sitting under a pile of dust in a museum warehouse?