A PHYLOGENY FOR GRASSHOPPERS OF THE GENUS CHITAURA (ORTHOPTERA, ACRIDIDAE) FROM SULAWESI, INDONESIA, BASED ON MITOCHONDRIAL-DNA SEQUENCE DATA

The Indonesian island of Sulawesi occupies a central position within t he biogeographically complex region known as Wallacea. Its fauna is ch aracterised by a high rate of endemism and a patchwork distribution of taxa within the island. The grasshopper genus Chitaura is a good exam ple having at least ten endemic species with predominantly parapatric distributions. It can be used as a model for determining the origins o f Sulawesi taxa and the within-island evolution that has led to the pr esent patterns of distribution. Here we present a phylogenetic hypothe sis for 28 individuals within the genus, including individuals of one species from Java and two from the Moluccas, based on DNA sequences of the mitochondrial cytochrome oxidase 1 gene. Frequent sequence hetero plasmy was observed. The phylogenetic hypothesis is consistent with re cent interpretations of the geological history of Sulawesi suggesting separate evolution on the island for 7-14 Myr, possibly since South Su lawesi was connected to Borneo. Within the island, the pattern of gene tic divergence is dominated by a strong correlation with geographic di stance, with exceptions indicating past or present barriers to dispers al. Colonisation of the Moluccas from North or Central Sulawesi is imp lied. Levels of genetic divergence are compared with distribution patt erns of colour morphs and with possible effects of tectonic movements in the Cenozoic, or Pleistocene climatic, vegetational and sea-level c hanges. (C) 1997 The Linnean Society of London.