Morphology, hybridization, and the conservation of North American species of Canis

I first review and evaluate the morphological evidence presented in past investigations that argue the red wolf (Canis rufus) is morphologically distinct from the coyote (C. latrans) and the gray wolf (C. lupus) and is a unique evolutionary lineage. I conclude that morphology remains a largely untapped resource for illuminating evolutionary and taxonomic questions and that past studies are difficult to evaluate from a phylogenetic viewpoint. The diagnostic value of the majority of characters reported to be diagnostic between Canis species has not been demonstrated. Multivariate studies have emphasized separation in multivariate space, not the identification of diagnostic character states so how the Canis species differ from each other remains largely unquantified. Studies using multivariate statistics are also ambiguous as to whether the observed patterns are caused by recent hybridization. In order to determine which of the hypothesized origins of the red wolf is best supported by morphology, or the taxonomic status for the red wolf that is best supported by morphology, the interspecific and intraspecific distributions of characters reported to be diagnostic among Canis species need to be quantified.;Finally I expand that data set by reporting on the interspecific and intraspecific distributions of dental characters in the gray wolf, coyote, and red wolf. Thirty two dental measurements and the presence or absence of 7 nonmensural characters were taken from the same specimens as the cranial measurements. Measurements were chosen that reflect specific dental characters that have been reported to be diagnostic between Canis species but generally never quantified. Early red wolves were indistinguishable from gray wolves in the morphology of the premolars but were coyote-like in the size of the incisors and the size and cone morphology of the molars. This unique combination of dental characters makes the red wolf morphologically distinct from gray wolves and coyotes. These results demonstrating the distributions of cranial and dental characters within and between North American Canis species provide a comparative data set for captive bred and wild hybrid populations in order to quantify the morphological impacts of hybridization on Canis populations of conservation interest.;Next I quantify the interspecific and intraspecific distribution of cranial characters in the gray wolf, the coyote, and the red wolf to verify that the red wolf has a unique morphology and to quantify the specific morphological characters that distinguish the red wolf from gray wolves and coyotes. I took 26 cranial measurements and recorded the presence or absence of 6 nonmensural characters on 124 coyotes and 119 gray wolves from throughout their geographic ranges and compared them to a sample 29 pre 1930 red wolves. I measured specific cranial characters that have been reported to be diagnostic between Canis species but generally never quantified. Coyotes and gray wolves are morphologically distinct in most characters although overlap is present in all characters except size. Early red wolves had a unique combination of gray-wolf like and coyote-like characters. Only a few cranial characters in the red wolf sample were intermediate between coyotes and gray wolves.