UN NUEVO LAGOSUCHIDAE (THECODONTIA-PSEUDOSUCHIA) DE LA FAUNA DE LOS CHAÑARES (EDAD REPTIL CHAÑARENSE, TRIASICO MEDIO), LA RIOJA, ARGENTINA

Andrea Arcucci

Abstract


Based on incomplete hind limb, pelvis and vertebrae, a new lagosuchid pseudosuchian from Los Chañares fauna (Chanarian Reptile Age, Middle Triassic) of La Rioja, Argentina, is described. Pseudolagosuchus maior gen. et sp. nov. share derived characters with Lagosuchus: femur shorter than tibia, size and shape of the fourth trocanter, structure of astragalus and calcaneum, advanced mesotarsal tarsus. Pseudolagosuchus is different fonn Lagosuchus for the ratios of length and stoutness between femur and pubis, the lengthening of sacral and caudal vertebrae, the latter with long neural spínes and elongated prezigapofisis, and for its bigger size. It is recognized a morphologícal variety of the tarsí wíthin the mesotarsal condition of the Los Chañares thecodonts.

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