Skeletal variation within the darwinii group of Liolaemus (Iguania: Liolaemidae): new characters, identification of polymorphisms and new synapomorphies for subclades

Fifty-five 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. lavillai, L. ornatus, L. quilmes, plus L. inacayali (L. telsen group) and L. scapularis (L. wiegmannii group). We report polymorphic intraspecific variation that has not previously been 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. The enclosure of Meckel's cartilage by a dentary outgrowth on lingual side of lower jaw (a synapomorphy of the subgenus Liolaemus sensu stricto and of the Phymaturus patagonicus group) also occurs within the L. darwinii group. The morphology of maxillary teeth with three conspicuous cusps may be a potential synapomorphy of the subgenus Eulaemus. The morphology of maxillary teeth may have adaptive value. Characters that were studied in other groups of lizards were informative for Liolaemus.