From niger (“black”) + thōrāx (“thorax”). <span class="searchmatch">nigrithōrāx</span> (genitive nigrithōrācis); third-declension one-termination adjective (New Latin) having a black...
thus normally in the nominative singular; other inflections may be theoretical or rarely found. Third-declension one-termination adjective. <span class="searchmatch">nigrithōrāx</span>...