Caves are a very special environment characterized by complete darkness, low temperature fluctuations and high humidity. Species that live there have adapted to these conditions and have developed unique characteristics: they are eyeless or have degenerated eyes, and they lack pigments. Often, these animals are endemic—their distribution is restricted to a specific area, sometimes to only one cave. Similarly, the four species of the blind cave shrimp Typhlocaris can be found only in individual karstic groundwater caves around the Mediterranean Sea. Two of the species are found in Israel – Typhlocaris galilea in a cave in Tabgha, near the Sea of Galilee, and Typhlocaris ayyaloni in the Ayalon cave, which was discovered in the coastal plain of Israel in 2006. The two other species are found in a cave system in southeastern Italy, near Lecce, and in Libya in a cave near Benghazi. A group of scientists from Israel and from the GEOMAR Helmholtz Centre for Ocean Research Kiel have now been able to prove a close relationship of a species in Israel and in Italy with the help of genetic and geological investigations. The study is published today in the scientific journal PeerJ.