Insights and benefits from monocot palaeobiology: DNA, fossils and phylogenetic analyses

In the last decade, there has been an increase in the integration of fossil data with molecular studies to answer critical questions on the origin, diversification and relationships of various plant groups and for the calibration of the tree of life. This is because the fossil record holds unique and considerable power for addressing these questions as fossils provide solid data on the presence, absence and distribution of taxa over the course of the history of the Earth. From them, it is possible to infer when, how and why changes have occurred, which has impacts on other areas of research, such as the prediction of future ecosystem responses to anthropogenic climate change. The fossil record is also crucial in systematic studies, which cannot be complete without the unique insights into diversity and novel combinations of characters offered by extinct taxa. Indeed, fossils are fundamental for the testing and more robust resolution of hypotheses based on morphological and molecular evidence alone. Undoubtedly, further integration of palaeoand neobotanical studies, with greater awareness of the strengths and weaknesses of the fossil record, is needed. This is particularly evident for the monocotyledon flowering plants. The monocots, which form a monophyletic clade sister to the eudicots (APG III, 2009), constitute c. 22% of angiosperm species, with c. 3000 genera and 60 000 species in c. 70 families. They include some of the most economically and ecologically important groups of plants, such as grasses (Poaceae; including bamboo, maize and wheat), palms (Arecaceae; including date palm, coconuts and oil palm) and the only marine angiosperms, the seagrasses (various families of Alismatales). Nevertheless, for many decades, the monocot fossil record was considered scarce because of the low probability of fossilization (being generally herbaceous, with annual reproduction and insect pollination, among other reasons) as pointed out previously (Daghlian, 1981; Herendeen & Crane, 1995; Gandolfo, Nixon & Crepet, 2000; Stockey, 2006; Smith, 2013). This, added to the fact that the putative apomorphies listed for the group (see APG III, 2009) are not unique to the monocots, and almost none is suitable for fossilization, makes the recognition of fossil monocots challenging. Nevertheless, fossils that preserve and show specific combinations of characters can be related with confidence to extant taxa and, although monocot palaeobiology still remains understudied as a result of these issues, significant advances are constantly being made. During the Fifth International Conference on Comparative Biology of Monocotyledons (Monocots V), held in New York City in 2013, a symposium on monocot palaeobiology was organized with the idea of bringing together researchers using a historical approach in their studies, including the investigation of the timing and evolution of lineages, origins of major ecosystems and biogeography, with the main goal of promoting the benefits of monocot palaeobiological studies and demonstrating how the fossil record can be used in combination with morphological and molecular evidence to address important questions. The symposium was dedicated to highlighting the recent advances made in understanding the monocot fossil record and its critical value in combination with extant taxa and modern techniques for addressing the origin, diversification, relationships and biogeography of the flowering plants in general. bs_bs_banner