Genus: Najash APESTEGUIA & ZAHER, 2006
Etymology: Hebrew, Najash, the legged biblical snake.
Species: rionegrina APESTEGUIA & ZAHER, 2006
Etymology: In reference to the Rio Negro Province of Argentina, where the specimens were found.
Holotype: MPCA 390-398, 400
Locality: 'La Buitrera', Rio Negro Province, Argentina.
Horizon: Upper section of the Candeleros Formation.
Age: Cenomanian Stage, Upper Gallic Subepoch, Lowermost Gulf Epoch, Middle Cretaceous-Turonian Stage, upper Gallic subepoch, lower Gulf Epoch, Early Late Cretaceous.
Material: Large fragment of the left dentary and anterior portion of the corresponding splenial, and a nearly complete articulated postcranial skeleton composed of several sections bearing a total of 122 articulated and associated vertebrae (109 presacrals, 2 sacrals, and 11 caudals), pelvic girdle, femora, fibula and proximal head of right tibia.
MPCA 385: Posterior half of a non-associated braincase with its right otico-occipital region preserved and several assiociated presacral vertebrae.
MPCA 380-383: Several disarticulated cranial and vertebral elements of a larger individual, including an incomplete left dentary, axis, and associated presacral and caudal vertebrae.
APESTEGIA & GARBEROGLIO, 2013/GARBEROGLIO, APESTEGUIA, SIMOES, PALCI, GOMEZ, NYDAM, LARSSON, LEE, CALDWELL, 2019
MPCA 386: Partial skull.
MPCA 419: Dentary wiht associated vertebrae and ribs.
MPCA 480: PArtial skull wiht atlas.
MPCA 500: Skull wiht atlas-axis.
MPCA 536: Partial skull.
MPCA 564: Articulated specimen with partial skull and postcranium.
MPCA 581: PArtial skull with atlas.
MPCA 591: Partial skull with articulated vertebrae.