Phylogenetic and ecological inference of three Halichoeres (Perciformes: Labridae) species through geometric morphometrics
A study of geometric morphometrics was carried out based on 109 specimens of four Labridae species captured in north-eastern Brazil. The canonical variable analysis applied on the W Matrix discriminated the species, and the partial warps analysis located the morphological variations. According to analysis, the Halichoeres species constitute a monophyletic group, with H. poeyi as the sister-group of the clade H. brasiliensis + H. dimidiatus. The cladogram of these species was estimated using Bodianus rufus as outgroup. The Halichoeres species share shorter head lengths and deeper heads in relation to the outgroup. Within Halichoeres, the more basal taxon (H. poeyi) can be characterized by autapomorphies such as short snout and deeper head. In the clade H. brasiliensis + H. dimidiatus, the snout is longer and the caudal peduncle is deeper than in H. poeyi. The results obtained from the geometric morphometry are consistent with works of functional morphology and their applications for the testing of phylogenetic hypotheses are equally satisfactory. However, caution is necessary because the similarities in morphometric data can reflect non-homologous and convergent features due to ecological roles, without representing kinships.