ärˌkēgōˈsȯrəs noun
Usage: capitalized
Etymology: New Latin, from Greek archēgos primary, originating (from archē beginning + -ēgos, akin to Greek agein to lead, drive) + New Latin -saurus — more at archi- , agent
: a genus of extinct long-snouted aquatic labyrinthodont amphibians from the Lower Permian of Europe