Figure 7. Geographical distribution of three species of Hyporthodus in the Atlantic Ocean and Mediterranean Sea, and localities where specimens of Pseudorhabdosynochus sulamericanus were collected.

Hyporthodus haifensis is only known from the Mediterranean Sea and African coasts of the Eastern Atlantic; H. niveatus and H. nigritus are American species. The distributions of the American and African species do not overlap, and are separated by the span of the Atlantic Ocean (Heemstra & Randall, 1993).