Publications resulting from this research: 

Carr, T. D. and T. E. Williamson. 2002. Evolution of basal Tyrannosauroidea from North America. Journal of Vertebrate Paleontology 22:41A (Abstract).

Clemens, W. A. and T. E. Williamson. 2005. A new species of Eoconodon (Triisodontidae, Mammalia) from the San Juan Basin, New Mexico. Journal of Vertebrate Paleontology 25:208-213.

Janis, C. M., J. D. Archibald, R. L. Cifelli, S. G. Lucas, C. R. Schaff, R. M. Schoch, and T. E. Williamson. 1998. Archaic ungulates and ungulate-like mammals, pp. 247-259, in C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), Evolution of Tertiary Mammals of North America. Cambridge, Cambridge University Press.

Libed, S. A., S. G. Lucas, P. E. Kondrashov, and T. E. Williamson. 2000. Taxonomic revision of the genus Periptychus, a Paleocene “condylarth” form the San Juan Basin, New Mexico. New Mexico Geology 22: (Abstract).

Lofgren, D. L., J. A. Lillegraven, W. A. Clemens, P. D. Gingerich, and T. E. Williamson. 2004. Paleocene biochronology of North America: The Puercan through Clarkforkian land mammal ages, Pp. 43-105, In M. O. Woodburne (ed.), The first North American land mammal ages of the Cenozoic Era, University of California Press.

Lucas, S. G., R. M. Schoch, and T. E. Williamson. 1998. Taeniodonta, in C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), Evolution of Tertiary Mammals of North America. Cambridge, Cambridge University Press.

Lucas, S. G. and T. E. Williamson. 1993a. Late Cretaceous to early Eocene vertebrate biostratigraphy and biochronology of the San Juan Basin, New Mexico.  New Mexico Museum of Natural History and Science, Bulletin 3:93-104.

Lucas, S. G. and T. E. Williamson. 1993b. A new taeniodont from the Paleocene of the San Juan Basin, New Mexico and the phylogeny of the Taeniodonta.  Journal of Mammalogy 74:175-179.

Lucas, S. G. and Williamson, T. E. 1995. Systematic position and biochronological significance of Yuodon and Palasiodon, supposed Paleocene "condylarths" from China. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 196:93-107.

Lucas, S. G., T. E. Williamson, and M. Middleton. 1997. Catopsalis (Mammalia: Multituberculata) from the Paleocene of New Mexico and Utah: taxonomy and biochronological significance.  Journal of Paleontology 71:484-493.

McKinney, K. C., R. H. Tedford, and T. E. Williamson. 2002. CD-ROM Archives – “Report Upon the Extinct Vertebrata Obtained in New Mexico by Parties of the Expedition of 1874,” by Edward D. Cope, with Multimedia Annotations. Geological Society of America, Abstracts with Programs 34 (Abstract).

O’Leary, M. A., S. G. Lucas, and T. E. Williamson. 2000. A new specimen of Ankalagon (Mammalia, Mesonychia) and evidence of sexual dimorphism in mesonychians. Journal of Vertebrate Paleontology 20:387-393.

Sealey, P. L., T. E. Williamson, and T. D. Carr. 2001. New material of Ellipsodon and assessment of its relationship to other Mioclaenidae (Mammalia, “Condylarthra”). Journal of Vertebrate Paleontology 21:100A (Abstract).

Stidham, T. and T. E. Williamson. 2007. A unique derived possibly zygodactyl bird skeleton from the Paleocene (Torrejonian) of New Mexico. Journal of Vertebrate Paleontology 27:152A (Abstract).

Weil, A. and T. E. Williamson. 2004. Successive multituberculate mammal assemblages in the Campanian – early Paleocene of the San Juan Basin, New Mexico. Geological Society of America Abstracts with Programs 36:179 (Abstract).

Weil, A. and T. E. Williamson. 2007. Late Cretaceous through earliest Tertiary evolution of multituberculate mammals in the San Juan Basin of New Mexico, and their biogeographic context.” Joint South-Central and North-Central Sections, Geological Society Abstracts with Programs 39:15 (Abstract).

Williamson, T. E. 1993a. Nacimiento Formation stratigraphy and biostratigraphy:  implications for Paleocene tectonism and evolution of the San Juan Basin, New Mexico.  New Mexico Geology 15:73 (Abstract)

Williamson, T. E. 1993b. The Beginning of the Age of Mammals in the San Juan Basin:  Biostratigraphy and Evolution of Paleocene Mammals of the Nacimiento Formation.  Ph.D. Dissertation, University of New Mexico, Albuquerque, 473 pp.

Williamson, T. E. 1993c. Mammalian biostratigraphy of the Nacimiento Formation, San Juan Basin, New Mexico and early Paleocene biochronology.  Journal of Vertebrate Paleontology 13:63A (Abstract).

Williamson, T. E. 1996. The beginning of the age of mammals in the San Juan Basin, New Mexico: biostratigraphy and evolution of Paleocene Mammals of the Nacimiento Formation.  New Mexico Museum of Natural History Bulletin 8, 141 pp.

Williamson, T. E. 2005a. First record of Eoconodon gaudrianus in the late Puercan of New Mexico. New Mexico Geology 27:54 (Abstract).

Williamson, T. E. 2005b. The To2-To3 transition in the San Juan Basin, New Mexico. New Mexico Geology (Abstract) 27:52.

Williamson, T. E. 2007. Mammal recovery following the terminal Cretaceous mass extinction. Western Interior Paleontology Society Meeting, Abstract with Programs, p. 55 (Abstract).

Williamson, T. E. 2007. Exceptional preservation of mammals, a bird, and lizards from the lower Paleocene of New Mexico. Journal of Vertebrate Paleontology 27:166A (Abstract).

Williamson, T. E. 2008. Early Paleocene mammal succession in the Nacimiento Formation, San Juan Basin, New Mexico. Geological Society of America, Abstracts With Programs, p. 325 (Abstract).

Williamson, T. E. and T. D. Carr. 2004. Microclaenodon (Mammalia) revisited. Journal of Vertebrate Paleontology 24:130A (Abstract).

Williamson, T. E. and T. D. Carr. 2005c. A phylogeny of the Mioclaeninae. Journal of Vertebrate Paleontology 25:130A (Abstract).

Williamson, T. E. and T. D. Carr. 2007. Bomburia and Ellipsodon (Mammalia, Mioclaenidae) from the early Paleocene of New Mexico. Journal of Paleontology 81:966-985.

Williamson, T. E. and T. D. Carr. 2007. Revision of the problematic early Paleocene genus Oxyclaenus (Mammalia: Oxyclaenidae) and a new species of Carcinodon. Journal of Vertebrate Paleontology 27:973-986.

Williamson, T. E. and S. G. Lucas. 1990. A new taeniodont from the Early Paleocene (Puercan) of the San Juan Basin, New Mexico.  Journal of Vertebrate Paleontology 10:49A (Abstract).

Williamson, T. E. and S. G. Lucas. 1991a. Early Paleocene freshwater stingrays and a sawfish? from the San Juan Basin, New Mexico. Journal of Vertebrate Paleontology 11:62A (Abstract).

Williamson, T. E. and S. G. Lucas. 1991b. Type section of the Paleocene Nacimiento Formation, San Juan Basin, northwestern New Mexico.  New Mexico Geology 13:61 (Abstract).

Williamson, T. E. and S. G. Lucas. 1992a. Internal stratigraphy of the Paleocene Nacimiento Formation, San Juan Basin, New Mexico.  New Mexico Geology 14:77 (Abstract).

Williamson, T. E. and S. G. Lucas. 1992b. Stratigraphy and mammalian biostratigraphy of the Paleocene Nacimiento Formation, southern San Juan Basin, New Mexico. New Mexico Geological Society, Guidebook 43:265-296.

Williamson, T. E. and S. G. Lucas. 1993a. Paleocene vertebrate paleontology of the San Juan Basin, New Mexico.  New Mexico Museum of Natural History, Bulletin 3:105-136.

Williamson, T. E. and S. G. Lucas. 1993b. Freshwater selachians from the early Paleocene of the San Juan Basin, northwestern New Mexico, USA.  Tertiary Research 14:1-9.

Williamson, T. E. and S. G. Lucas. 1993. Paleocene-Eocene boundary in the San Juan Basin, New Mexico-Colorado. Journal of Vertebrate Paleontology 13:63A (Abstract).

Williamson, T. E. and S. G. Lucas. 1997a. The Chico Springs locality, Nacimiento Formation, San Juan Basin, New Mexico.  New Mexico Geological Society, Guidebook 48:259-265.

Williamson, T. E. and S. G. Lucas. 1997b. The Paleocene Chico Springs locality, Nacimiento Formation, San Juan Basin, New Mexico.  New Mexico Geology 19   (Abstract).

Williamson, T. E., S. G. Lucas and J. W. Froehlich. 1994. Skeleton of a new leptictid? from the early Paleocene (Torrejonian) of the Nacimiento Formation, San Juan Basin, New Mexico.  Geological Society of America Abstracts with Programs 26 (Abstract).

Williamson, T. E., S. G. Lucas and J. W. Froehlich. 1994. New genus and species of early Paleocene (Torrejonian) leptictid? from the Nacimiento Formation, San Juan Basin, New Mexico. Journal of Vertebrate Paleontology 14:52A (Abstract).

Williamson, T. E., S. G. Lucas and R. M. Sullivan. 1991. What is the Puercan-Torrejonian boundary?  Geological Society of America, Rocky Mountain Section, Abstracts with Programs 23:106 (Abstract).

Williamson, T. E. and D. Nichols. 2007. Paleocene palynomorph assemblages from the Nacimiento Formation, San Juan Basin, New Mexico. New Mexico Geology. 29:63 (Abstract).

Williamson, T. E., D. Nichols, and A. Weil. 2008. Paleocene palynomorph assemblages from the Nacimiento Formation, San Juan Basin, New Mexico. New Mexico Geology 30:3-11.

Williamson, T. E. and P. L. Sealey. 2000. A juvenile Pantolambda bathmodon (Mammalia: Pantodonta) from the early Paleocene (Torrejonian) Nacimiento Formation, San Juan Basin, New Mexico. New Mexico Geology 22: (Abstract).

Williamson, T. E. and A. Weil. 2001. New microvertebrate localities in the Upper Cretaceous Fruitland and Kirtland formations, San Juan Basin, New Mexico. New Mexico Geology 23:64 (Abstract).

Williamson, T. E. and A. Weil. 2002a. A late Puercan (Pu3) microfauna from the San Juan Basin, New Mexico. Journal of Vertebrate Paleontology 22:119A (Abstract).

Williamson, T. E. and A. Weil. 2002b. A new late Puercan (early Paleocene) local Fauna from the San Juan Basin, New Mexico: A preliminary report. New Mexico Geology 24 (Abstract).

Williamson, T. E. and A. Weil. 2004. Earliest Cenozoic mammalian faunal succession in the San Juan Basin, New Mexico. Geological Society of America Abstracts with Programs 36:179 (Abstract).

Williamson, T. E. and A. Weil. 2008a. Therian mammals from the Naashoibito Member, Kirtland Formation, San Juan Basin, New Mexico and their biochronologic and paleobiogeographic significance. Journal of Vertebrate Paleontology 28:803-815.

Suggested reading:

Alroy, J. 1999. "The fossil record of North American mammals; evidence for a Paleocene evolutionary radiation." Systematic Biology 48(1): 107-118.

Asher, R. J., J. Meng, et al. 2005. "Stem Lagomorpha and the antiquity of Glires." Science 307: 1091-1094.

Bininda-Emonds, O. R. P., M. Cardillo, et al. 2007. "The delayed rise of present-day mammals." Nature 446-512.

Cope, E. D. 1884. The Vertebrata of the Tertiary formations of the West, Volume III, Tertiary vertebrates, book 1. Washington.

Hunter, J. P. and C. M. Janis. 2006. "Spiny Norman in the Garden of Eden? Dispersal and early biogeography of Placentalia." Journal of Mammalian Evolution 13: 89-123.

Kues, B. S. 2008. The Paleontology of New Mexico. Albuquerque: University of New Mexico Press. 428 pp.

Matthew, W. D. 1937. Paleocene faunas of the San Juan Basin, New Mexico [edited by Walter Granger, William King Gregory, and Edwin Harris Colbert]. Transactions of the American Philosophical Society, 30(510).

Springer, M. S., E. C. Murphy, et al. 2003. "Placental mammal diversification and the Cretaceous-Tertiary boundary." Proceedings of the National Academy of Sciences 100(3): 1056-1061.

Sullivan, R. M., A. Boere, et al. 2005. "Redescription of the ceratopsid dinosaur Torosaurus utahensis (Gilmore, 1946) and a revision of the genus." Journal of Paleontology 79: 577-595.

Wible, J. R., G. W. Rougier, et al. 2007. "Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary." Nature 447: 1003-1006.

Williamson, T. E. and A. Weil. 2008. "Metatherian Mammals from the Naashoibito Member, Kirtland Formation, San Juan Basin, New Mexico and Their Biochronologic and Paleobiogeographic Significance." Journal of Vertebrate Paleontology. Vol. 28(3): 803-815.