 The skull was structured in such a way that as it closed , the bones holding the teeth in the upper jaw would bow out . This would cause the lower surfaces of the upper jaw teeth to rub against the upper surface of the lower jaw 's teeth , grinding anything caught in between and providing an action that is the rough equivalent of mammalian chewing . Because the teeth were always replaced , the animal could have used this mechanism throughout its life , and could eat tough plant material . Additionally , the front ends of the animal 's jaws were toothless and tipped with bony nodes , both upper and lower , providing a rough margin that was likely covered and lengthened by a keratinous material to form a cropping beak for biting off twigs and shoots . Its food gathering would have been aided by its flexible little finger , which could have been used to manipulate objects , unlike the other fingers . 
 The skull was structured in such a way that as it closed , the bones holding the teeth in the upper jaw would bow out . This would cause the lower surfaces of the upper jaw teeth to rub against the upper surface of the lower jaw <a href='null_genetive' title='1'><mark>'s</mark></a>teeth , grinding anything caught in between and providing an action <a href='null_relcl' title='2'><mark>that</mark></a><a href='drop_aux' title='3'><mark>is</mark></a>the rough equivalent of mammalian chewing . Because the teeth <a href='uninflect' title='4'><mark>were</mark></a> always replaced , the animal could <a href='been_done' title='5'><mark>have</mark></a> used this mechanism throughout its life , and could eat tough plant material . Additionally , the front ends of the animal <a href='null_genetive' title='6'><mark>'s</mark></a>jaws <a href='uninflect' title='7'><mark>were</mark></a> toothless and tipped with bony nodes , both upper and lower , providing a rough margin <a href='null_relcl' title='8'><mark>that</mark></a>was likely covered and lengthened by a keratinous material to form a cropping beak for biting off twigs and shoots . Its food gathering would <a href='been_done' title='9'><mark>have</mark></a> been aided by its flexible little finger , which could <a href='been_done' title='10'><mark>have</mark></a> been used to manipulate objects , unlike the other fingers . 
Da skull was structured in such a way that as it closed , the bones holdin tdateeth in the upper jaw would bow out . dis would cuz thdaower surfaces of thedaper jaw teef to rub against the daer surface of the lower jaw  teeth , grinding anything caught in between and providing an action the rough equivalent of mammalian chewing . Because the tteefwas always replaced , the adaal could done used tdismechanism throughout its life , and could eat tough plant material . Additionally , the frda ends of the animal  jaws was toothless and tipped with bony nodes , both upper and lower , providing a rough margin was likely covered and lengthened by a keratinous material to form a cropping beak for bitin offf twigs and shoots . Its food gathering would done been aided by its flexible little finger , which could done been used to manipulate objects , unlike the other fingers .