Anochetus isolatus Mann, n. status

(Fig. 2)

Anochetus cato subsp. isolatus Mann, 1919, Bull. Mus. Comp. Zoo!., 03:302, fig. 11, worker, male. Type locality: Graciosa Bay, Santa Cruz. (Syntypes examined - MCZ.)

Material examined. SANTA CRUZ: Graciosa Bay (syntypes). Mann also recorded this species from Malapaina, Three Sisters Group, Solomons, on which island it occurs sympatrically with the closely related A. cato Forel .

Taxonomic note. A. isolatus forms with A. splendens (Aru), A. seminiger (Waigeo), and A. splendidulus (Carolines), the " isolatus superspecies," i.e., a tightly-knit group of cognate forms which seem sufficiently well differentiated to be good biological species, but which are completely allopatric in distribution. Actually, treatment of these four forms as species must be considered arbitrary until evidence is obtained of non-intergradation in areas of overlap, if indeed such areas exist at all.

The range of the isolatus superspecies forms a nearly complete circle around that of the related species cato . Brown (Quart. Rev. Biol., 32:271, 1957) has suggested that this unusual pattern may have resulted from the replacement of isolatus in New Guinea, Bismarck Archipelago, and western Solomons by the more recently evolved rato.