Skeletal variation within the <em>darwinii</em> group of <em>Liolaemus</em> (Iguania: Liolaemidae): new characters, identification of polymorphisms and new synapomorphies for subclades
A total of 55 skeletal characters (continuous and discrete) were analyzed for species of the L. darwinii group: L. albiceps, L. chacoensis, L. grosseorum, L. irregularis, L. koslowskyi, L. ornatus, L. quilmes, plus L. inacayali (L. telsen group) and L. scapularis (L. wiegmannii group). We report polymorphic intraspecific variation that was not previously taken into account and we describe 21 new characters that provide original information across the group. We detected several morphological synapomorphies for the darwinii group and subclades. Meckel’s cartilage enclosed by dentary outgrowth on lingual side of lower jaw (synapomorphy of the subgenus Liolaemus sensu stricto, and of the patagonicus group of Phymaturus) occurs also within the L. darwinii group. The morphology of maxillary teeth with three conspicuous cusps can be a potential synapomorphy of the Eulaemus subgenus. As we show in the present study, the morphology of maxillary teeth can have an adaptive value. Characters that were studied in other groups of lizards were informative for Liolaemus.