Ignacius graybullianus


Ignacius graybullianus had a body mass around 152 grams (Fleagle, 1999). This species had a dental formula of 1:0:1:3 or 1:0:2:3 on the lower jaw (Conroy, 1990). This species shows reduction in the antemolar teeth (Conroy, 1990). Ignacius species, like other plesiadapiforms, have enlarged and protruding lower incisors (Conroy, 1990). This species had low crowned molars with blunt cusps and shallow basins (Conroy, 1990). The face is long and narrow of the species and possessed a large infraorbital foramen (Fleagle, 1999). Fleagle (1999) suggests that features suggest a richly innervated snout with tactile vibrissae. This species had the auditory bulla composed of the entotympanic bone (Fleagle, 1999). Ignacius graybullianus lacks the grooves for the promontory artery (Conroy, 1990).

Ignacius graybullianus was found in North America (Rocky Mountain region) between the middle Paleocene to late Eocene epochs (Fleagle, 1999; Conroy, 1990; Rose and Gingerich, 1977).


Conroy, G.C. 1990. Primate Evolution. W.W. Norton and Co.: New York.

Fleagle, J.G. 1999. Primate Adaptation and Evolution. Academic Press: San Diego.

Rose, K. and Gingerich, P. 1977. Partial skull of the plesiadapiform primate Ignacius from the early Eocene of Wyoming. Mus. Paleontol. Univ. Mich. Vol. 24, 181-189.

Last updated: July 14, 2005

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