These rare and elegant species are among the few ant genera that have their center of diversity based in the Pacific Islands. After revising the taxonomy of the Fijian taxa and describing five new species, I worked with Andrea Lucky on a molecular-based phylogeny to test hypotheses concerning the group’s biogeographical origins. Our phylogeny and divergence estimates were based on four nuclear genes (28S, ArgK, LW Rh, CAD), and data on Indo-Pacific geological history was used to address current hypotheses regarding the origins of the Fijian biota. Our results suggest the genus Lordomyrma probably originated in mainland Asia, with subsequent colonization of Australia and the Pacific. The Fijian Lordomyrma clade is monophyletic, and originated c. 8.8 Ma, when it diverged from a sister group in Papua New Guinea. The colonization of Fiji by Lordomyrma is probably a result of long-distance dispersal from New Guinea, possibly aided by island hopping across the Vitiaz Arc. The timeline of diversification in Lordomyrma is broadly congruent with the Miocene fragmentation of the Vitiaz Arc and the Pliocene emergence of Vanua Levu. The biotic shuttle hypothesis, which posits ‘Eua Island as the source of Fijian endemics, was rejected based on the sister relationship of Fiji and New Guinea lineages, as well as on the Miocene submergence of the terrane below sea level. The diversity of Fijian Lordomyrma results from the radiation of a single lineage, which diverged from a New Guinea sister group. The genus appears to have originated in Asia rather than in Australia.
Identification guide to Fijian Lordomyrma. Illustrated Lucid Phoenix key and webpages for all species.
Lucky, A & EM Sarnat (2010) Biogeography and diversification of the Pacific ant genus Lordomyrma Emery. Journal of Biogeography 37: 624-634. [pdf]
Lucky, A & EM Sarnat (2007) New species of Lordomyrma (Hymenoptera: Formicidae) from Southeast Asia and Fiji. Zootaxa 1681: 37-46. [pdf]
Sarnat, EM (2006) Lordomyrma (Hymenoptera: Formicidae) of the Fiji Islands. In: Evenhuis, N.L. & Bickel, D.J. (eds.), Fiji Arthropods. IX.Bishop Museum Occasional Papers 90: 9-42. [pdf]