Global history of the ancient monocot family Araceae inferred with models accounting for past continental positions and previous ranges based on fossils

Abstract

Summary• The family Araceae (3790 species, 117 genera) has one of the oldest fossil records among angiosperms. Ecologically, members of this family range from free-floating aquatics (Pistia and Lemna) to tropical epiphytes. Here, we infer some of the macroevolutionary processes that have led to the worldwide range of this family and test how the inclusion of fossil (formerly occupied) geographical ranges affects biogeographical reconstructions.• Using a complete genus-level phylogeny from plastid sequences and outgroups representing the 13 other Alismatales families, we estimate divergence times by applying different clock models and reconstruct range shifts under different models of past continental connectivity, with or without the incorporation of fossil locations.• Araceae began to diversify in the Early Cretaceous (when the breakup of Pangea was in its final stages), and all eight subfamilies existed before the K ⁄ T boundary. Early lineages persist in Laurasia, with several relatively recent entries into Africa, South America, South-East Asia and Australia.• Water-associated habitats appear to be ancestral in the family, and DNA substitution rates are especially high in free-floating Araceae. Past distributions inferred when fossils are included differ in nontrivial ways from those without fossils. Our complete genus-level time-scale for the Araceae may prove to be useful for ecological and physiological studies.

The genome of the seagrass Zostera marina reveals angiosperm adaptation to the sea

“…A starting tree with branch lengths satisfying all fossil prior constraints was created according to the consensus APGIII phylogeny 71 . Fossil calibrations were implemented using log-normal calibration priors on the following nodes: the node uniting the Malvidae based on the fossil Dressiantha bicarpellata 72 The offsets of these calibrations represent hard minimum boundaries, while their means represent locations for their respective peak mass probabilities in accordance with some of the most recent and taxonomically complete dating studies available for these specific clades 14,80 . A run without data was performed to ensure proper placement of the marginal calibration prior distributions 81 .…”

“…Duplicated segments account for ~9% of the Z. marina genome, probably an underestimate due to the fragmented nature of the assembly. Zostera and Spirodela diverged somewhere between 135 and 107 million years ago (Mya) 14 and…”

Taxonomy of duckweeds (Lemnaceae), potential new crop plants

“…However, the branching appears to have started about 104 Ma ago in the Early Cretaceous when the breakup of Pangea was in its final stage (Nauheimer et al, 2012). This is one reason why we prefer keeping Lemnaceae as a family of its own .…”

“…The monophyly does not necessarily mean that duckweeds have to be integrated into the family of Araceae and be treated as a subfamily Lemnoideae, as preferred e.g. by Nauheimer et al (2012). One can separate the small group of Protoaraceae together with Lemnaceae from the "true Araceae" (as these two groups are the most basal elements in this group), which results in three monophyletic plant families, i.e.…”

First identification of natural products from the African medicinal plant Zamioculcas zamiifolia — A drought resistant survivor through millions of years

“…1) is an ancient plant species of the Araceae, a family which dates back to the early Cretaceous period, a geologic time period approximately 100-130 million years ago [1]. Fossils of plants of the Araceae family have been discovered [2,3].…”