FIG. 5.

Host species ranges of the light organ symbionts P. mandapamensis and P. leiognathi. Species of fish that harbor P. mandapamensis and species of fish and squid that harbor P. leiognathi are shown with host family and order in parentheses. Hosts reported are those for which detailed analysis of bacteria has been carried out using methods that discriminate between P. mandapamensis and P. leiognathi. Most leiognathids harbor apparently only P. leiognathi, whereas all examined specimens of S. versicolor and the one available specimen of G. jordani harbored only P. mandapamensis. In light organs of some fishes (A. japonicum, P. panayensis, and P. bindus), P. mandapamensis and P. leiognathi occur as cosymbionts. Nonetheless, the host ranges of these two bacterial species are substantially distinct.