Complex sentence: The Japanese spurdog, "Squalus japonicus", is a dogfish, a member of the family Squalidae, found in the western Pacific Ocean from southeastern Japan and the East China Sea, including the Republic of Korea, the Philippines, and the Arafura Sea.
Split into simpler sentences: The Japanese spurdog, "Squalus japonicus", is a dogfish, a member of the family Squalidae. It is found in the western Pacific Ocean--southeastern Japan and the East China Sea, including the Republic of Korea, the Philippines, and the Arafura Sea.