THE UPPER TRIASSIC OF WESTERN TEXAS. 



47 



opposite the upper edge of the cotylus there is a decided prominence; below this the 

 edge of the bone is quite thin. The lower and anterior edges of the coracoid have been 

 injured by decay, but could not have had a very much greater extent. 



Measurements of Desmatosuckus. 



em. 



Length of skull on right side 27.4 



Width of skull at posterior end 16.4 



Length of axis and atlas at base 7.6 



Length, anteiior end of skull to first sacral 198.6 



Length of huge spine along outside curve 39.4 



Same with extreme tip, now lost, added 40.9 



Extent of long spine from mid-line 41 .2 



Average length of mid-dorsal plate 16.8 



Average length of same, antero-posterior 8.4 



The restoration (fig. 20). In the attempted restoration consideration has been 

 given to several factors. It is obvious that such an animal as Desmatosuchus, with its 

 spiny armor, would have considerable difficulty in making progress through tangled 

 vegetation, either aquatic or terrestrial, and it is in accord with this character and the 

 suggestion of the sediments that sparse vegetation and open water are indicated in the 

 environment. It must be remembered 

 in considering the nature of the animal 

 that its remains are very limited in 

 quantity in a region where the remains 

 of Phytosaurs are relatively abundant. 

 It would appear that Desmatosuchus 

 inhabited a region somewhat different 

 from that occupied by Belodon and 

 Mystriosuchus, either more remote from 

 the pools which formed the favorable 

 environment of more common forms or 

 a region geographically remote from 

 the locality where the collection was 

 made. It is exceedingly unfortunate 

 that no teeth were found with the 

 specimen, and so no more than a guess 

 can be made of the nature of its food; 

 but as the sockets are simp'e and 

 rounded, it is safe to assume the teeth 

 were single cones and that the animal 

 was carnivorous. Inhabiting an area of 

 open land, it is probable that the animal must have had relatively long limbs, a prob- 

 ability borne out by the size of the pelvis and the shape of the acetabulum, and further 

 by the facts that no short limb-bones were found in the locality and that the frag- 

 ment of the shaft of a limb-bone found with Desmatosuchus is evidently part of a long 

 femur or humerus. No trace of the feet or claws was found, and the suggestion of par- 

 tially webbed feet, implying a dominantly aquatic habitat, may be erroneous. The 

 weight of the great carapace would, perhaps, also be an objection to the assumption of an 

 aquatic life. For the same reason the possibility that the habitat was not dominantly 

 aquatic it is possible that the tail has been made too long and too much of a swimming 

 organ. 



Critical study of the specimen in the course of mounting the skeleton has led to 

 the conclusion that the plates of the dorsal armor did not overlap when the animal was 

 in a normal position, but overextension, as by a strong upward curvature of the body, 

 would have been possible only by the overlapping of the plates. This is the condition 

 found in the modern Crocodilia. 



FlG ' ^.Desmatos^hus 



A. 



Anterior view of the distal portion of the seapula-eoracoid ' 



right side. X 0.3. 

 B. Outer view of A. X 0.3. 



