Diversity and diversification of E umolpinae ( C oleoptera: C hrysomelidae) in N ew C aledonia

Contemporary taxonomic work on N ew C aledonian E umolpinae ( C hrysomelidae) has revealed their high species richness in this W estern P acific biodiversity hotspot. To estimate total species richness in this community, we used rapid DNA ‐based biodiversity assessment tools, exploring mtDNA diversity and phylogenetic structure in a sample of 840 specimens across the main island. Concordance of morphospecies delimitation with units delimited by phenetic and phylogenetic algorithms revealed some 98–110 species in our sample, twice as many as currently described. Sample‐based rarefaction curves and species estimators using these species counts doubled this figure (up to 210 species), a realistic estimate considering taxonomic coverage, local endemism, and characteristics of sampling design, amongst others. N ew C aledonia, compared with larger tropical islands, stands out as a hotspot for E umolpinae biodiversity. Molecular dating using either chrysomelid specific rates or tree calibration using palaeogeographical data dated the root of the ingroup tree (not necessarily a monophyletic radiation) at 38.5 Mya, implying colonizations after the C retaceous breakage of G ondwana. Our data are compatible with the slowdown in diversification rates through time and are also consistent with recent faunal origins, possibly reflecting niche occupancy after an initial rapid diversification. Environmental factors (e.g. soil characteristics) seemingly played a role in this diversification process. © 2013 The Linnean Society of London