Two New Species of Liolaemus Lizards from Northwestern Argentina: Speciation within the Northern Subclade of the Elongatus Group (iguania: Liolaemidae)

The Liolaemus elongatus group currently includes eight species (including the species described herein) of mid-sized, long-tailed, primarily saxicolous lizards. Members of this lineage are distributed in northwestern Argentina along the Andean Cordillera south to the Patagonian Steppe (27–448 S) and over a wide range of elevations (350–3900 m). Here we describe two new species belonging to the northern radiation of the elongatus group. The four currently recognized members of this northern subclade (including the two species described herein) have fewer midbody scales than other members of the elongatus group, brown to black heads, and lack the distinct dorsal body or tail patterns found in adults of other species belonging to the elongatus group. Additionally, pregnant and recently spent females exhibit crimson red color in the cloacal region—a trait known only for members of this northern lineage and L. buergeri. The first new species, L. dicktracyi from the Sierra de Famatina of La Rioja Province, differs from all other members of the elongatus group in several meristic characters and in its unique dorsal coloration: black heads, shoulders, and tails, with blue torsos and hind limbs. The second new species, L. umbrifer from the Quebrada de Randolfo in northeastern Catamarca Province, is morphologically similar to L. capillitas, but differs from this and other species in the elongatus group in several meristic characters, the presence of black shoulders and upper arms, and crimson red coloration of the cloacal region in both males and females. The natural history of both of the new species is similar in many respects to L. capillitas and L. heliodermis, which further supports the phylogenetic affinities of members of this subclade within the elongatus group. Finally, we provide comparisons of recent phylogenetic hypotheses and discuss the content of the elongatus group.