Molecular Phylogeny of Nepenthaceae Based on Cladistic Analysis of Plastid trnK Intron Sequence Data

Nepenthaceae are an exceptional family with regard to carnivo ry and the uniformity of characters. This makes it dif- ficult to resolve phylogenetic relationships due to conv ergent evolution of morphological features. Using comparative se- quencing of the chloroplast trnK intron, the monophyly of this complex family and hypoth eses of infrageneric relationships were tested. Sequences from 71 Nepenthes taxa, representing all groups and two taxa of the closely related Ancistrocladaceae and Dioncophyllaceae as outgroup, were determined and ana- lysed using maximum parsimony methods. Results of this analy- sis show that the isolated taxa N. distillatoria (Sri Lanka) and N. pervillei (Seychelles) are the most basal, clearly separated from the Madagascan taxa N. madagascariensis and N. masoalensis which are placed in a distinct subclade. This corresponds with some plesiomorphic character s shared by these taxa. N. khasi- ana (North India) has an intermediate position between these relic Western species and the remaining taxa. The species of the Malay Archipelago can be referred to three distinct lineages which indicate a correlation to biogeography . Thus the recent disjunct distribution of Nepenthes is interpreted as a result of an incisive extinction of progenitors, a process of migration and a subsequent diversification on the islands of Borneo, Sumatra, Sulawesi and New Guinea. Based on our molecular data, two in- terpretations concerning the origin of Nepenthes are possible: i) evolution in the Northern Tethys which is suppor ted by fossil pollen records from the European Focene, or , ii) a Gondwana- land origin at a time when the Indian plate was separated from Madagascar. Molecular data indicate that colonization of SE Asia started from an ancient Indian stock. Subsequently, in the Malay Archipelago a new secondary centre of diversity developed. Ma- dagascar, the Se ychelles and New Caledonia were probably reached by migration via land bridges, starting from widespead common ancestors with subsequent extinction leaving the cur- rent taxa. There is no evidence for long-distance dispersal. Cur- rent infragenic classification of Nepenthes is only partly in accordance with the phylogen y inferred from trnK intron data.