Phylogenetics, phylogeography and vicariance of polyphyletic Grammosciadium (Apiaceae: Careae) in Anatolia

Abstract

Detailed phylogenetic relationships, evolutionary histories and phylogeographical hypotheses are still quite rare for the many genera of Apiaceae. One of the reasons for this is that traditional generic circumscriptions based on morphology and anatomy largely failed to recognize the group as monophyletic. This is also true for apioid members of Apiaceae with c. 400 genera. Here we focus on Grammosciadium s.l. centred in Turkey and unravel its evolutionary history. Based on three loci from the plastid genome and nuclear-encoded internal transcribed spacer regions 1 and 2 from the nuclear encoded ribosomal RNA operon, we show that Grammosciadium in its current circumscription is not monophyletic and represents an assemblage of species from four genera (Carum, Chamaesciadium, Fuernrohria, Grammosciadium). Diversification of this group started c. 7 Mya in the late Miocene. Most present-day species arose during the Pliocene with most of the intra-species diversification occurring during the Pleistocene. Plastome type variation does not resolve any of the main clades and there is little spatial structure of the distribution of high plastid genetic variation. The majority of species of pre-Quarternary origin are found east of the Anatolian Diagonal, running diagonally across central and eastern Turkey. This might indicate that the Diagonal acted as a barrier to gene flow and migration during the Pliocene and that eastern Anatolia may have served as a cradle for Pleistocene diversification and speciation processes in Turkey. We also provide a key to the species of the revised genus and introduce several taxonomic changes.