Zospeum tholussum, a very tiny, transparent snail, was declared one of the “Top 10 New Species of 2014” by the International Institute for Species Exploration. During a caving expedition in 2010 in the Lukinajama-Trojama cave system in Croatia, a live specimen was discovered at a depth of about 980 meters. Its stature as a top 10 species came about because of its habitat of complete darkness in a cave.
This true cave-dwelling species from the family Ellobiidae is air-breathing and blind as in complete darkness there would be no reason for eyes! Its shell is translucent with 5 to 6 whorls and the entire snail is microscopic – its shell height measures less than 2 mm (0.08 inches) while its shell width is only about 1 mm (0.04 inches). It is very tiny indeed! It is so slow-moving it may only move a few millimeters in a week’s time. Because of Zospeum tholussum‘s extremely slow locomotion, it is thought it gets help to move longer distances through running water or hopping a ride with larger organisms also known as passive transport.
With its thin shell and translucent design Zospeum tholussum presents a ghost-like image. It is an amazing find and beautiful addition to our known biodiversity.