A new genus and species of marine reptile is described from the Pelsonian (Anisian, Middle Triassic) of Luoping County, Yunnan Province, southwestern China. This diapsid reptile with a secondarily closed upper temporal fossa is the sister taxon to Saurosphargis from the lower Muschelkalk (Anisian, Middle Triassic) of central Europe. It further emphasizes the close faunal affinities between the Eastern and Western Tethyan realm. The new taxon is convergent on cyamodontoid placodonts in having developed a dorsal body armor composed of small osteoderms. The underlying ribs are transversely broadened so as to establish contact along their length, thus forming a closed dorsal ‘rib basket,’ a unique morphology shared with Saurosphargis.