Dr. Xiaoming Wang (xwang@nhm.org), Associate Curator of Vertebrate Paleontology, Natural History Museum of Los Angeles County

In collaboration with Dr. Richard Tedford at the American Museum of Natural History (New York City), we are working on several projects on extinct fossil dogs, the family Canidae (ancestral wolves, coyotes, foxes, etc.). The project is aimed at resolving the genealogical relationships among a diverse group of fossil canids in the middle through late Tertiary (approximately 34 to 2 million years ago) of North America. These fossil "dogs" play an important role as top predators of their time, and many had similar adaptations as living hyenas. The Frick Collections at the American Museum of Natural History has the best collection of fossil canids, and much of these were previously unknown to science. Using a modern method called cladistics and with the help of sophisticated computer programs, we attempt to decipher the evolutionary relationships among the extinct dogs. We will then place their geological and geographical occurrences under this new evolutionary framework and search for their paleoenvironmental implications.

History and Diversity

    Canids originated in the late Eocene more than 40 million years ago.  As the most ancient group in the order Carnivora, the family Canidae is the first to emerge from the more archaic group of Miacidae.  The phylogenetic relationships of the Canidae indicates that it is the most primitive among the dog-like carnivores (Caniformia) and is a sister to the Arctoidea.  Ancestral canid (in the subfamily Hesperocyoninae) begins to have a ossified bony middle ear cavity and elongated limbs adapted for fast running.

    There are three major radiations of the family Canidae: the subfamilies Hesperocyoninae, Borophaginae, and Caninae.  Modern canids are all grouped within the last subfamily Caninae.  Through careful observations of their skull and dental features, we can reconstruct their phylogenetic relationships.

Subfamily Hesperocyoninae.  This is the most ancient and archaic group of canid.  Originated and remained in North America, this group of canid became dominate carnivores of its time.

•     Hesperocyon gregarius
•     Mesocyon coryphaeus
•     Enhydrocyon basilatus

Subfamily Borophaginae.  Commonly known as the hyenoid dogs, this is the largest and most diverse group of ancient canids.  The Borophaginae is confined to North America during its entire existence.  Species in this group span a wide spectrum of ecological niches from raccoon-like omnivores to hyena-like top predators.  Some of the more charismatic species has been the subjects of artistic reconstructions and public fascination.  The subfamily became extinct shortly before the Pleistocene.

•     Otarocyon cooki
•     Cynarctus crucidens
•     Aelurodon taxoides
•     Borophagus diversidens

Subfamily Caninae.  This group contains all of the living canids in the world.  The world-wide distribution of modern canids is the result of their migrations during the late Cenozoic in the last 5 million years or so.

Our works on this last subfamily is still in progress.  As in the subfamilies Hesperocyoninae and Borophaginae, we will attempt a detailed, species-level phylogenetic analysis of the Caninae.  The result will be published in the Bulletin of the American Museum of Natural History

Major References on Evolution of Canidae

Wang, X., R. H. Tedford, and B. E. Taylor. 1999.  Phylogenetic systematics of the Borophaginae (Carnivora: Canidae). Bulletin of the American Museum of Natural History, 243: 1-391.

Wang, X., and R. H. Tedford. 1996.  Canidae. In D. R. Prothero and R. J. Emry (eds.), The Terrestrial Eocene-Oligocene Transition in North America, Part II: Common Vertebrates of the White River Chronofauna. Cambridge University Press, Cambridge, pp. 433-452.

Tedford, R. H., B. E. Taylor, and X. Wang. 1995.  Phylogeny of the Canidae (Carnivora: Canidae): the living taxa. American Museum Novitates, 3146: 1-37.

Wang, X. 1994.  Phylogenetic systematics of the Hesperocyoninae (Carnivora: Canidae). Bulletin of the American Museum of Natural History, 221: 1-207.

Wang, X., and R. H. Tedford. 1994.  Basicranial anatomy and phylogeny of primitive canid and closely related miacids. American Museum Novitates, 3092: 1-34.

Wang, X. 1993.  Transformation from plantigrady to digitigrady: functional morphology of locomotion in Hesperocyon (Canidae: Carnivora). American Museum Novitates, 3069: 1-23.

Wang, X., and B. M. Rothschild. 1992.  Multiple hereditary osteochondroma in Oligocene Hesperocyon (Canidae: Carnivora). Journal of Vertebrate Paleontology, 12 (3): 387-394.

Wang, X. and R. H. Tedford. 1992.  The status of genus Nothocyon Matthew, 1899 (Carnivora): an arctoid not a canid. Journal of Vertebrate Paleontology, 12 (2): 223-229.

Wang, X. 1990.  Systematics, functional morphology, and evolution of primitive Canidae (Mammalia: Carnivora). Doctoral dissertation, Department of Systematics and Ecology, University of Kansas, Lawrence, pp. 222.

Comments and questions?  Contact Dr. Xiaoming Wang at xwang@nhm.org