including Arctocyon (known as/similar to Claenodon in North America), Arctocyonides, Landenodon, and Mentoclaenodon, found in the late Paleocene layers...

certainly a specialized member of the group. Similar to Arctocyon was Arctocyonides, also found in the French Palaeocene deposits but of smaller dimensions...

north Kent. The formation has provided fossils of the eutherian mammal Arctocyonides arenae. Upnor Formation at Fossilworks.org "Upnor Formation". The BGS...

Eocene Creechbarrow Limestone Formation  United Kingdom An early bat. Arctocyonides jefferyi Valid Hooker Early Eocene Blackheath Formation  United Kingdom...