Island life – classification, speciation and cryptic species of P ycnandra ( S apotaceae) in N ew C aledonia

P ycnandra ( S apotaceae), the largest endemic genus in N ew C aledonia, comprises 66 species classified in six subgenera. We tested phylogenetic relationships and a proposed infrageneric classification by sampling 60 species for sequences of nuclear ribosomal DNA ( ETS , ITS , RPB2 ) and plastid DNA ( trnH–psb A ) and nine morphological characters. Data were analysed with B ayesian inference, parsimony jackknifing and lineage through time. We recovered a phylogenetic tree supporting the recognition of six proposed subgenera ( A chradotypus , L eptostylis , P ycnandra , S ebertia , T rouettia and W agapensia ). Because a subgeneric classification is used, the nomenclature will be stable when the members are transferred to P ycnandra . Morphological traits were optimized in the BEAST analysis, adding evidence to earlier work that morphology has limited value for successfully diagnosing groups in S apotaceae. We confirm a previously suspected case of cryptic species that exhibit the same morphological features and require the same abiotic conditions, but are distantly related in the phylogenetic tree. We detected two possible new cases of cryptic sibling species that might warrant recognition. A slowdown in speciation rate in several genera has been suggested as evidence that N ew C aledonia was once submerged after rifting from A ustralia. Plotting lineages through time reveals two important intervals at 7.5–8.6 Ma and present to 1.5 Ma, when net molecular diversification within the genus was zero. This indicates that the genus presently has reached a dynamic equilibrium, providing additional evidence that N ew C aledonia is an old Darwinian island, being submerged during the Eocene and colonized after re‐emergence c . 37 Ma. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society , 2015, 179 , 57–77.