Speaker
Description
The Mediterranean Sea, known for its high biodiversity and endemic species, has experienced significant geological events that shaped its current biological landscape. This study focuses on gutless oligochaetes, which rely entirely on symbiotic bacteria for nutrition, and explores their evolutionary path and population structure across the Mediterranean. Gutless oligochaetes and other marine species could have colonized the Mediterranean in two ways. First, from east to west: The ancient Mediterranean was once connected to the Tethys Ocean, allowing colonization from the modern Indian Ocean. The Mediterranean became nearly landlocked and dried out during the Messinian Salinity Crisis (MSC) about 6 million years ago. While most authors argue that all marine life became extinct, some suggest species survived in marine refuges. The second colonization path is from west to east when the Mediterranean reflooded with Atlantic Ocean water about 5.3 million years ago. We are using population genomics to reveal how the gutless oligochaete Olavius algarvensis colonized the Mediterranean, and how and when it acquired its symbiotic consortium of five to six bacterial species. Our initial results show distinct genetic structuring in both host and symbiont populations across the Mediterranean Basin, indicating complex evolutionary dynamics. This research enhances our understanding of how ancient geological events and symbiotic relationships shape marine biodiversity, providing insights into the evolutionary history of Mediterranean fauna.
