- suborder: Plesiadapiformes
- superfamily: Plesiadapoidea
- family: Palaechthonidae
Palaechthon nacimienti had a relatively small braincase (Fleagle, 1988). This species had a short premaxilla (Kay and Cartmill, 1977; cited in Martin, 1990). This species had small orbits, directed laterally, and a broad interorbital region (Fleagle, 1988). A broad interorbital region may suggest a large olfactory fossa and this would suggest a greater reliance on the sense of smell (Fleagle, 1988). This species possessed a large infraorbital foramen (Fleagle, 1988). This species had an average body mass of around 150 grams (Fleagle, 1988). This species had a dental formula of 2:1:3:3 on both the upper and lower jaw (Martin, 1990).
Palaechthon nacimienti was found on the continent of North America and occurred during the middle Paleocene (Fleagle, 1988).
Based upon dental morphology this species was most likely an insectivore (Kay and Cartmill, 1977; cited in Conroy, 1990).
Conroy, G.C. 1990. Primate Evolution. W.W. Norton and Co.: New York.
Fleagle, J.G. 1988. Primate Adaptation and Evolution. Academic Press: New York.
Kay, R.F. and Cartmill, M. 1977. Cranial Morphology and Adaptation of Palaechthon nacimienti and Other Paromomyidae (Plesiadapoidea, Primates), with a Description of a New Genus and Species. Journal of Human Evolution, Vol. 6, 19-53.
Martin, R.D. 1990. Primate Origins and Evolution: A Phylogenetic Reconstruction. Princeton University Press: Princeton, New Jersey.
Last updated: November 15, 2001