Two species of Palaeochiropterygidae,
Palaeochiropteryx tupaiodon and
P. spiegeli, are known from complete skeletons from the famous Messel Pit fossil deposits in Germany.
Palaeochiropteryx tupaiodon is the most common mammal found at Messel. An additional species of
Palaeochiropteryx,
P. sambuceus, has been described from the middle Eocene of North America. All other species belonging to Palaeochiropterygidae are known only from isolated teeth and jaw fragments from
Europe,
India,
Turkey, and possibly
North America. At Messel, the two species of
Palaeochiropteryx are hypothesized to have occupied similar niches to living
hipposiderids and
rhinolophids that forage close to the ground and among vegetation. Wings with low
aspect ratio and
wing loading and preserved stomach contents of small
moths and
caddisflies support the idea that these palaeochiropterygids were slow but maneuverable fliers. The widespread distribution of Palaeochiropterygidae among the northern continents in the early and middle Eocene conflicts with the known
morphology of
P. tupaiodon and
P. spiegeli, however, suggesting that other species of palaeochiropterygids had body plans much more suitable to long distance dispersal. == Evolutionary relationships ==