A lost species or the loss of stripes? The case of Contomastix lizards from Cabo Polonio, Uruguay, with observations on C. lacertoides (Duméril & Bibron) and Cnemidophorus grandensis Cope (Squamata, Teiidae)

Abstract

The main goal of this manuscript is the reevaluation of the taxonomic status of the teiid lizard Contomastix charrua, known only from Cabo Polonio, a small coastal rocky outcrop in southeastern Uruguay. This species was erected on the basis of the presence of a second pair of ceratobranchials and longer cornua in the hyoid bone, in addition to a reduced expression of the pattern of coloration as compared with C. lacertoides. Nevertheless, we found that both species have indistinguishable hyoid morphology, bearing C. lacertoides a noticeable second pair of ceratobranchials. Besides, we realized that the pattern of coloration in this species is more variable than previously considered. As a result of the present work, C. charrua is included in the synonymy of C. lacertoides. In addition, we provide some observations on the holotype of Cnemidophorus grandensis, a junior synonym of C. lacertoides.