Ecological factors such as the use of the environment and feeding habits may influence the body and cephalic morphology of an organism, however, this can also reflect the phylogenetic lineage. The subfamily Dipsadinae includes South American snakes formed by two clades, one including Geophis and Atractus and another including Dipsas, Ninia, Sibon and Sibynomorphus, which are the tribe Dipsadini. The snakes of this tribe show a high degree of modification in their body and cephalic morphology wich is related to the environment and malacophagous feeding habits. The species of Dipsas and Sibon have specializations related to the use of arboreal environment, offering a better performance in locomotion in the vegetation, while the Sibynomorphus species are mostly adapted to terrestrial environment. Regarding their feeding habits they posses, in varying degrees, a number of changes related to cranial modification and to manipulation and ingestion of gastropods such as slugs and snails. Whereas there is a direct relationship between the shape of the head and the diet, this study aims to analyze the divergences of cephalic morphology between species of diet related to Dipsas and Sibynomorphus, as well as analyze possible convergences between species of these genera and Tomodon dorsatus, species of the tribe Tachymenini, recognized as specialized in slugs. This study is structured in two parts: the first refers to the general introduction, where a broad approach on the morphological adaptations related to feeding habits of Dipsadini, as well as the advantages of the use of geometric morphometry technique in morphological studies; and the second part refers to the work itself, titled "Ecomorphology of three species of Dipsas Laurenti, 1768 and Sibynomorphus Fitzinger, 1843 (Dipsadidae: Dipsadinae)".
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