Research Description

My field and laboratory research is focused on paleobiological and biostratigraphic questions concerning the evolution of Mesozoic and Cenozoic terrestrial biotas. Currently I am studying the systematic interrelationships of Mesozoic mammals, making use of characters of both skeletal morphology and enamel microstructure. A stratigraphically controlled series of early Paleocene (Puercan) local faunas calibrated through 40Ar/39Ar age determinations provides the basis for analyses of the patterns and tempos of terrestrial faunal change during the first million years after the extinctions used to mark the end of the Cretaceous.

Graduate student research projects include: Investigation of the phylogenetic interrelationships, locomotor evolution, and turnover rates of Eocene artiodactyls; analysis of phylogenetic interrelationships and biogeographic distributions of Late Cretaceous and Early Cenozoic members of the Multituberculata; and study of the origins and evolutionary diversification of neornithine birds during the Late Cretaceous and Paleocene.

Selected Publications

Montellano, M., A. Weil and W.A. Clemens. 2000. An exceptional specimen of Cimexomys judithae (Mammalia: Multituberculata) from the Campanian Two Medicine Formation of Montana, and the phylogenetic status of Cimexomys. Journal of Vertebrate Paleontology 20(2):333-340.

Clemens, W. A. 2001. Patterns of mammalian evolution across the Cretaceous-Tertiary boundary. Mitteilungen aus dem Museum fŸr Naturkunde in Berlin, Zoologische Reihe 77:175-191.

Butler, P. M. and W.A. Clemens. 2001. Dental morphology of the Jurassic holotherian mammal, Amphitherium, with a discussion of the evolution of mammalian post-canine dental formulae. Palaeontology 44 (1): 1-20.

Wilson, G. P., and N. C. Arens. 2001. The evolutionary impact of an epeiric seaway on Late Cretaceous and Paleocene palynofloras of South America. VII International Symposium on Mesozoic Terrestrial Ecosystems. Asociaci—n Paleontol—gica Argentina, Publicaci—n Especial 7, pp. 185-189.

Wood, C. B., and W.A. Clemens. 2001. A new specimen and a functional re-association of the molar dentition of Batodon tenuis (Placentalia, incertae sedis), Latest Cretaceous (Lancian), North America. Bulletin, Museum of Comparative Zoology 156(1): 99-118.

Wood, C. B., and W.A. Clemens. 2001. A new specimen and a functional re-association of the molar dentition of Batodon tenuis (Placentalia, incertae sedis), Latest Cretaceous (Lancian), North America. Bulletin, Museum of Comparative Zoology 156(1): 99-118.

Clemens, W. A. 2002. Evolution of the mammalian fauna across the Cretaceous-Tertiary boundary in northeastern Montana and other areas of the Western Interior. Geological Society of America, Special Paper 361: 217-245.

Clemens, W. A. 1997. Characterization of enamel microstructure and application of the origins of prismatic structures in systematic analyses. In Tooth enamel microstructure, ed. W. V. Koenigswald, 85-112. Rotterdam: A. A. Balkema.

Kolodny, Y., B. Luz, M. Sander, and W. A. Clemens. 1996. Dinosaur bones: Fossils or pseudomorphs? The pitfalls of physiological reconstruction from apatitic fossils. Palaeogeog. Palaeoclimatol. Palaeoecol. 126:161-71.

Goodwin, M. B., W. A. Clemens, C. R. Schaff, and C. B. Wood. 1996. New occurences of Mesozoic vertebrates from the Upper Blue Nile Gorge and nearby tributaries, Ethiopia. J. Vertebr. Paleontol. 16 (suppl. to 3):38A.

Clemens, W. A. 1994. Continental vertebrates from the Late Cretaceous of the North Slope, Alaska. In 1992 Int. Conf. Arctic Margins, Proceedings, 395-98. U.S. Dept. Interior, Minerals Management Service. OCS Study MMS 94-0040.

Theodor, J. A. 1994. Artiodactyl phylogeny: Whither Diacodexis? J. Vertebr. Paleontol. 14 (suppl. to no. 3):49A.

Weil, A. 1994. K/T suvivorship as a test of Acid Rain Hypothesis. Geol. Soc. Am. 26(7):A335.