About every decade I ask the DML the following question: What is the current time-stratigraphic status of _Purgatorius_ (found in screening material from the (?)Hell Creek Fm). Have any new specimens clarified whether it is a Upper Cretaceous species?
Who cares? :-)The *Maelestes* paper (cited below) found *Purgatorius*, *Protungulatum* and *Oxyprimus* to form the sister-group of Placentalia. If this is anywhere near correct, we can simply forget about *Purgatorius* as long as we're only interested in the origin of primates. So I have simply stopped worrying. :-)
Of course, this result has yet to be tested more properly. While big, the matrix still wasn't big enough (work is being done on this); there are correlated characters and the like in it (work is being done on this, too); and all characters were unordered, something that can have a drastic impact on the topology.
I don't know of any additional specimens, but I don't follow the primary literature on that kind of animal.
J. R. Wible, G. W. Rougier, M. J. Novacek & R. J. Asher: Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary, Nature 447, 1003 -- 1006 (21 June 2007)