▁that ▁was ▁from ▁three ▁to ▁three ▁and ▁a ▁half ▁metres ▁long ▁and ▁we ighed ▁about ▁ 3 0 0 ▁kil og rams . ▁It ▁belongs ▁to ▁the ▁family ▁Case idae . ▁Like ▁its ▁contemporary , ▁another ▁case id , ▁Cot yl or h yn chus , ▁it ▁was ▁large , ▁heavily ▁built , ▁and ▁her b iv orous . ▁It ▁also ▁shared ▁its ▁environment ▁with ▁the ▁case ids ▁Case o ides ▁and ▁Case opsis . ▁It ▁may ▁have ▁been ▁pre yed ▁upon ▁by ▁the ▁large ▁s phen ac od ont ▁p ely c osa ur ▁Dim et rod on . ▁ ▁Like ▁all ▁case ids , ▁Angel osa urus ▁was ▁an ▁evolution arily ▁conserv ative ▁re pt ile ▁which ▁would ▁appear ▁to ▁have ▁been ▁one ▁of ▁the ▁dominant ▁her b iv ores ▁of ▁the ▁time , ▁occup ying ▁a ▁similar ▁e colog ical ▁role ▁to ▁c ows . ▁Case id ▁sk ull s ▁are ▁distinguished ▁from ▁other ▁p ely c osa urs ▁by ▁large ▁temporal ▁open ings , ▁large ▁nas al ▁and ▁p ine al ▁open ings ▁and ▁an ▁upper ▁j aw ▁that ▁distinct ively ▁over hang s ▁the ▁teeth ▁of ▁the ▁lower ▁j aw . ▁The ▁sk ull ▁is ▁p itted . ▁The ▁teeth ▁are ▁uniform . ▁The ▁body ▁was ▁probably ▁bar rel - sh aped , ▁like ▁other ▁case ids , ▁with ▁massive ▁lim bs ▁and ▁small ▁cer v ical ▁verte bra e . ▁And ▁unlike ▁the ▁better - known ▁p ely c osa urs ▁such ▁as ▁Dim et rod on