Decumarellus sarbui is the first cave genus belonging to the Tyrini in the whole world; such a genus of the Tyrini tribe has never been signaled in a cave. It lives in Movile Cave, near Mangalia, Constanţa County, Southeastern Romania. The species is endemic for the chemoautotrophically based groundwater ecosystem at Mangalia and unique in the world.
Scientific name: Decumarellus sarbui Poggi, 1994
The genus Decumarellus is dedicated to the Romanian bio-speleologist Vasile Decu and at the same time reminds of the un-doubtful relationship with the genus Marellus. The species (sarbui) is dedicated to Romanian scientist Dr. Şerban M. Sârbu, from the Department of Biological Sciences of the Cincinnati University, USA.
Decumarellus sarbui shows the typical morphological adaptations to the live in caves. It might be the extreme result of the differentiation of a branch of the genus Marellus, which settled down in the hypogeus habitat and evolved independently, at least since the possibility of a link between the cave and the surface fauna came to a stop. According to the geological, hydrological and palaeo-geographical data, the isolation of the cave goes back to the end of Miocene (almost 5.5-5.2 millions of years ago) when the climate of the Southern Dobrogea got extremely dry in connection with the crisis of salinity from Messinian.