Gimme shelter: Seven new leech species call freshwater mussels home

(North Carolina Museum of Natural Sciences) The frequent presence of leeches with a hidden lifestyle in the mantle cavity of freshwater mussels has been recorded since the second half of the 19th century. Yet this was, until now, regarded as an accidental phenomenon. Recent research not only reveals seven mussel-associated leech species new to science, but also shows that their association evolved over millions of years.