Canini Fischer de Waldheim, 1817

TEDFORD R. H., WANG X. & TAYLOR B. E., 2009, Phylogenetic Systematics Of The North American Fossil Caninae (Carnivora: Canidae), Bulletin of the American Museum of Natural History 2009 (325), pp. 1-218 : 77-78

Tribe Canini Fischer de Waldheim, 1817

The living dogs, wolves, coyotes, jackals, and so-called foxes or zorros of South America were morphologically characterized as the sister group of the Vulpini at branching-point H in figure 2 of Tedford et al. (1995). The critical features that mark the Canini as a monophyletic group include the consistent enlargement of the frontal sinus, often accompanied by the correlated loss of the depression in the dorsal surface of the postorbital process; the posterior expansion of the paroccipital process; the enlargement of the mastoid process; and the lack of lateral flare of the orbital border of the zygoma.

In this work we assume the monophyly of the South American Canini based on our previous investigation ( Tedford et al., 1995) while acknowledging the contradictions posed by biomolecular systematic work ( Wayne et al., 1997) regarding the polyphyly of some taxa. The core taxa within the ‘‘South American foxes’’ of Wayne et al. (1997) remain phyletically associated in combined analysis of morphologic and molecular evidence ( Wayne et al., 1997: fig. 7). The most parsimonious combined evidence tree is reasonably robust in bootstrap analysis, and its form contains groups of sister taxa common to both approaches.

Beyond the early appearance of a clade of large hypercarnivores ( Protocyon and Theriodictis ; Berta, 1988) related to the recently extinct Falkland Island fox ( Dusicyon australis ), the South American fossil record adds little information on phylogeny other than that contributed by the living taxa. The span of this record approximates the latest Pliocene and Pleistocene ( Tonni et al., 1992, 1999) and is largely restricted to Andean and southern South America ( Berta, 1987). Amazonian records are limited to the latest Pleistocene.

We have, however, been able to recognize fossil species in North America that can be placed in or close to living species of Cerdocyon and Chrysocyon , and possibly the extinct Theriodictis , that indicate these South American forms had representatives in the Northern Hemisphere in the earliest Pliocene and early Pleistocene, respectively. This evidence implies that clades within the South American Canini were forming in northern latitudes well before 3 Ma when the opportunity to move south across the Panamanian Isthmus first arose ( Keigwin, 1978). Taxa identified as Canis sp. and Pseudalopex sp. appear first in Argentina ( Tonni et al., 1992), and by the earliest Pleistocene most of the South American clades are in place. Sequence divergence data for the South American canids ( Wayne et al., 1997) leads to similar conclusions regarding the appearance of this fauna. Similarly, Nyctereutes appears in eastern Asia at the beginning of the Pliocene ( Tedford and Qiu, 1991), indicating westward expansion of this putative South American clade into the Old World before the opportunity to invade South America arose. Because of strong evidence from morphology and history we have formalized the ‘‘South American canids’’ as a new subtribe, Cerdocyonina , to emphasize its probable monophyly.

The phylogenetic analysis presented herein shows that species of the extinct genus Eucyon Tedford and Qiu (1996) have a sister relationship to all other species of Canis rather than lying at the base of the Canini . This clade (subtribe Canina , new rank) was restricted to North America for most of the late Miocene, but in the latest Miocene Eucyon appeared in Europe ( E. monticinensis Rook, 1992 ) and by the early Pliocene achieved a Holarctic-wide distribution with local centers of evolution yielding endemic Old World species (e.g., E. zhoui Tedford and Qiu, 1996 ) and taxa of higher rank (e.g., Nurocyon Sotnikova, 2006 ).

The Canina also contains species of Canis , Cuon , Lycaon , and Xenocyon . Canis expand- ed its range to Eurasia early in the Pliocene and by the Pleistocene was present in Africa as well. Its species arose in many quarters of the Old World, with those present in arctic Beringia eventually extending their ranges southward during the Pleistocene into midlatitude North America to augment the autochthonous canid fauna. Cuon and Xenocyon were rare visitors to North America during the Pleistocene, and the presence of species of these Old World genera has been mentioned by Repenning (1967) and Youngman (1993).