Arackar, a new titanosaur from Chile
In the 2021 we published a new and a relativelly small sauropod dinosaur discovered in the desert of Atacama, Chile. We named this new species Arackar licanantay, and the news was spread throughout the world. The presence of "small" titanosaurs such as Arackar from Chile and Saltasaurus, Neuquensaurus and Rocasaurus from Argentina, present at the end of the Cretaceous, seems to indicate a reduction in size of these herbivores before their extinction.
Strict consensus tree based on a data matrix of 87 taxa and 405 characters recovered Arackar licanantay as a derived lithostrotian titanosaur, placing it as a sister taxon of Isisaurus colberti and close to Rapetosaurus krausei (500 MPTs of 1323 steps, CI: 0.367; RI: 0.721). (Fig. 12 from Rubilar-Rogers et al. (2021)
Abstract. A new lithostrotian sauropod, Arackar licanantay gen. et sp. nov. is described based on a partial skeleton from the Upper Cretaceous (Campanian–Maastrichtian) beds of the Hornitos Formation, Atacama Region, northern Chile. The holotype consists of axial (cervical and dorsal vertebrae) and appendicular (humerus, femur and ischium) elements of a sub-adult specimen (ca. 6.3 m long). Autapomorphies characterizing this new titanosaur include: middle neural arches with wide and tall centroprezygapophyseal fossa + parapophyseal centroprezygapophyseal fossa (cprf + pacprf) extending on the entire anterior faces of the pedicles, but not above the neural canal, and reduced spinopostzygapophyseal laminae, shorter than the postzygapophyseal facet length. A phylogenetic analysis based on a data matrix of 87 taxa and 405 characters recovered Arackar as a derived lithostrotian titanosaur, placing it in a clade that includes Rapetosaurus + (Arackar + Isisaurus). This is the third dinosaur named from Chile and the third titanosaur from the western side of the Andes in South America.
REFERENCES
Rubilar-Rogers, D.; Vargas, A. O.; González Riga, B.; Soto-Acuña, S.; Alarcón-Muñoz, J.; Iriarte-Díaz, J.; Arévalo, C.; Gutstein, C. S. (2021). Arackar licanantay gen. et sp. nov. a new lithostrotian (Dinosauria, Sauropoda) from the Upper Cretaceous of the Atacama Region, northern Chile. Cretaceous Research. doi:10.1016/j.cretres.2021.104802.
SCIENTIFIC OUTREACH
2021. DIARIO LA NACION. Presentan una nueva especie de dinosaurio chileno: el Arackar licanantay - La Nación (lanacion.cl)
2021. DIARIO CLARIN. Un argentino participó del descubrimiento de una nueva especie de dinosaurio en Chile (clarin.com)
2021. DIARIO PAGINA 12. Bernardo González Riga | HECHO EN CASA | Página12 (pagina12.com.ar)
2021. DIARIO LOS ANDES. Gran hallazgo: un mendocino de la UNCuyo descubrió uno de los últimos titanosaurios en Chile | Sociedad (losandes.com.ar)
2021. DIARIO MDZ. Descubren restos de un dinosaurio nunca visto y un argentino participa del estudio - MDZ Online (mdzol.com)
2021. DIARIO VIA PAIS. Histórico hallazgo: mendocino descubre un Titanosaurio en el desierto chileno de Atacama | Vía Mendoza (viapais.com.ar)
