The objetive of this study was to include the lizard Stenocercus dumerilii (Steindachner, 1867) in the phylogenetic context of Tropidurinae*. Scale morphology, cranial anatomy, scapular girdle, abdominal skeleton, and hemipenis are described. Emphasis is given to characters used in phylogenetic studies including the genus Stenocercus. Sixty-five preserved specimens, two cleared and stained specimens, and two distended hemipenis have been examined. The characteristics studied agree with the generic placement of the species, considering its present definition. On the other hand, the species is unique within the genus Stenocercus by having only one pair of xiphisternal ribs, a depressed tail, postsupraciliar scales projected in the form of a horn (together with S. tricristatus), and enlarged parietal, postparietal and occipital scales forming a longitudinal sequence. Contrary to what has been generally considered, this species does not agree with the characteristics o f the informal "Ophryoessoides group". The main characteristics of S. dumerilii that exclude it from this species group are the arrangement of supraoculars and posterior head scales, and the distance between the pairs of post-xiphisternal ribs. It is concluded that S. dumerilii fits well within Tropidurinae* and the genus Stenocercus, but it is not part of the "Ophryoessoides group".
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