The importance of Messel for interpreting Eocene Holarctic mammalian faunas

The middle Eocene Messel fauna includes 34 genera and 46 species of mammals, most of which have close relatives or analogues in other Eocene faunas. Unlike most other Eocene fossil assemblages, however, the Messel mammal assemblage consists of an extraordinary number of nearly complete, articulated skeletons, often exquisitely preserved and sometimes revealing details of soft anatomy and stomach contents as well as osteology. Consequently, Messel fossils provide a wealth of anatomical and ecomorphological data that inform our understanding of the functional anatomy, behaviour and phylogenetic relationships of these animals and of related Eocene mammals from other faunas. Several examples are highlighted here, including the metatherians Amphiperatherium and "Peradectes," the pantolestan Buxolestes, the pholidotamorphs Eomanis and Eurotamandua, the possible stem macroscelidean Macrocranion, the leptictidan Leptictidium, the bats Hassianycteris and Archaeonycteris, the apatothere Heterohyus, and the artiodactyls Messelobunodon and Aumelasia. All of these Messel taxa have enhanced our knowledge of mammals from various North American and Asian faunas.