Recognition of Martellidendron , a new genus of Pandanaceae, and its biogeographic implications

Pandanaceae are an ancient family of dioecious monocots dating from the early to mid‐Cretaceous, and comprising three extant genera Sararanga , Freycinetia and Pandanus . We present a cladistic analysis of Pandanaceae based on DNA sequences of four cpDNA fragments (the trnL intron and three intergenic spacers, trnL ‐ F , trnS ‐ ycf 9 and atpB ‐ rbcL ) in order to elucidate intergeneric relationships within the family. The results show that Pandanus , as currently circumscribed, is biphyletic, with members of the Indian Ocean subg. Martellidendron sister to the Indo‐Malesian genus Freycinetia in a clade that also includes the Malesian genus Sararanga , and that the remaining members of Pandanus form a separate well supported clade. Martellidendron is thus recognized as a distinct genus, thereby circumscribing a monophyletic Pandanus . Martellidendron comprises seven species (for which new combinations are proposed). The high level of morphological differentiation between the genera of Pandanaceae suggests rapid early radiation as seen in other monocot groups. The molecular data also indicate that the distinct lineages of Pandanaceae in the Indian Ocean basin are likely the result of both vicariance ( Martellidendron ) and more recent step‐wise long‐distance dispersal from Asia across the Indian Ocean (e.g., monocarpellate spiniform species in lowland eastern Madagascar).