28 
A TOOTHLESS ARMOURED DINOSAUR FROM THE UPPER 
CRETACEOUS OF ALBERTA 
By C. M. Sternberg, Geological Survey, Canada 
Page 
70-77 
Illustrations 
Plates XVII to XX. Illustrations of Anodontosaurus lambei 
The Geological Survey's collection of vertebrate fossils contains a 
specimen of armoured dinosaur which reveals certain characters hitherto 
unknown among the Stegosauria. The specimen consists of skull, left 
mandibular ramus, one caudal vertebra with co-ossified chevron, one 
phalanx, and many dermal scutes. It was collected by G. F. Sternberg 
in 1916, from the Edmonton formation, 90 feet above Red Deer river, in sec. 3, 
tp. 21, range 31, W. 4th prin. mer. This locality is about 8 miles southwest 
of Morrin, Alberta, and the horizon is near the middle of the Edmonton 
beds. The specimen was preserved in a tenacious fine-grained sandstone 
which does not free well from some of the softer bones, particularly the 
under side of the skull and the roof of the mouth, thus making the prepara- 
tion of this portion difficult. 
The most unusual features of the specimen are the total absence 
of teeth and the development of bony plates to take their place on both 
the maxillae and dentaries; the reduction of the mandible; the great 
depression of the skull; and the thinness of the dermal scutes. This is 
the first toothless member of the Stegosauria to be recorded and the name 
Anodontosaurus lambei is proposed for its reception. The specific name 
is given in honour of the late L. M. Lambe, who was the first to describe 
armoured dinosaurs from the Cretaceous of Alberta. 
Future studies of the genus may show that it differs sufficiently 
from described forms to warrant placing it in a new subfamily, but for the 
present the differences are regarded as only of generic distinction. 
Anodontosaurus lambei gen. et. sp. nov. 
Type of species, No. 8530, Geological Survey, Canada. 
Generic and Specific Characters. Skull very much depressed; com- 
pletely covered with moderate-sized, irregular, dermal ossifications; 
broadly rounded in front; small overhanging occipital crest; external 
nares transversely elongate and terminally placed; orbit roughly lenticular 
in outline, placed moderately far back and facing outward; teeth absent, 
and broad, flat, bony plates for masticating food developed on maxillee 
and dentaries; pterygoids small and meeting on midline; palatines not 
fused on midline; mandible greatly reduced and without coronoid process; 
dermal scutes thin and concave interiorly, to correspond to the superior 
convexity. 
