How do you say arthropod in Japanese?
— 節足動物

Specialized synonyms for arthropod in Japanese
centipedeムカデ (mukade); 百足 (むかで, mukade); 蜈蜙; 蝍蛆
insect昆虫 (こんちゅう, konchū); 虫 (むし, mushi)
millipedeヤスデ