Skull of Palaechthon nacimienti

摘要: SPECIES in or near the ancestry of living primates first appear late Cretaceous and early Palaeocene North America. Subsequent adaptive radiation Purgatorius-like ancestral stock produced plesiadapoid families (Plesiadapidae, Carpolestidae, Paromomyidae) middle Palaeocene. Specialised members all three survived into Eocene, paromomyid genus Phenacolemur persisting Eocene. Most species are known only from incomplete dentitions. In 1948, a crushed but nearly complete skull was recovered strata age Kutz Canyon area San Juan Basin, New Mexico. The specimen has been described by Wilson Szalay1, who assign it to new (P. nacimienti) Palaechthon, also mid-Palaeocene Montana Wyoming. loss upper lower premolars excludes P. nacimienti some Eocene prosimian lineages. Nevertheless, its persistently primitive molar morphology suggests that may more closely resemble last common ancestor plesiadapoids modern aspect than do other for which cranial remains known. Skulls partial skulls dentally specialised genera each family: Plesiadapis (Plesiadapidae), Carpolestes (Carpolestidae), (Paromomyidae).) We present here reconstruction nacimienti, together with preliminary functional interpretations dental anatomy.