The skeleton including femora, tibiae, fibulae and incomplete parts of a scapula, humerus, ulna, left and right ischium, vertebrae, ribs, partial armor over the pelvic girdle plus at least 60 detached armor plates and 8 teeth was found in the Late Cretaceous (Upper Campanian) marine Point Loma Formation, near Carlsbad, California.
Donald F. Glut in 1982 reported it as either an iguanodont or hadrosaur, with no crest or boot on the ischium (both characteristics of the crested lambeosaurine duckbills), and suggested it could be the juvenile of a previously named genus like Tanius or Shantungosaurus.