Vol. 86, No. 23, pp. 279-298 28 September 1973 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON THE MONOTYPIC INDO-PACIFIC LABRID FISH GENERA LABRICHTHYS AND DIFROCT ACANTHUS WITH DESCRIPTION OF A NEW RELATED GENUS, LARABICUS By John E. Randall and Victor G. Springer Bernice P. Bishop Museum, Honolulu, Hawaii 96818, and Smithsonian Institution, Washington, D.C. 20560 The wrasse genus Labrichthys Bleeker (1854) has been a source of confusion to ichthyologists almost from its incep-tion. Giinther ( 1862 ) erred in uniting the genus Pseudolabrus Bleeker with Labrichthys. As a result, more species of Pseudo-labrus have been described and reported in Labrichthys than in the proper genus. Gill (1891) corrected this mistake, add-ing that Bleeker placed these two genera in different sub-families (his Labrichthyiformes and Pseudolabriformes ) . Labrichthys and its allies differ from Pseudolabrus (here compared only with the type-species of Pseudolabrus, P. ru-biginosus = P. japonicus ) in having five instead of six bran-chiostegal rays, tubes of lateral-line scales simple instead of ramose (but simple in young Pseudolabrus) , specialized denti-tion, a difference in mouth structure, and a reduced, weakly ossified lower pharyngeal bone with relatively few teeth which extend uniserially onto the anterior shank of the bone (figures 1-3) as opposed to a robust, heavily ossified lower pharyngeal bone with more teeth which extend irregularly biserially, or as a patch, onto the anterior shank of the bone (figure 4). Table 1 augments the comparison of pharyngeal bones, and is based on much larger specimens than were used for the pharyngeal bone illustrations. The difference in structure of the lower pharyngeal bones is undoubtedly correlated with diet: the labrichthyiform fishes feed on relatively soft-bodied 23— Proc. Biol. Soc. Wash., Vol. 86, 1973 (279)
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