Kew scientists find the oldest daisies were trampled by the last surviving dinosaurs
Release date: 11 August 2015
Fossil pollen grains from the Asteraceae or daisy family have been discovered in Antarctica by scientists from the Royal Botanic Gardens, Kew and colleagues in Argentina and New Zealand, drastically pushing back the assumed origin of this flowering plant lineage by twenty million years. This places the early evolution of daisies at the time of dinosaurs. The results are published today (10 August 2015) in the online Early Edition of PNAS.
Using the Antarctic findings, the team has also now been able to unambiguously place a number of other Cretaceous fossilised pollen grains from New Zealand in the Asteraceae family, implying that the Cretaceous distribution of this family was relatively broad. The researchers saw strong morphological similarities between these fossil pollen grains and those produced by some members of the Asteraceae family today.
The Asteraceae are the single most diverse family of flowering plants, with about 23,000 species, including garden favourites such as daisies, sunflowers and chrysanthemums, right through to lettuce and artichokes.
The fossil analysed had remained buried in deposits from the Late Cretaceous period of Antarctica for more than 65 million years and was found amongst extinct groups such as dinosaurs and Ammonites. This, and other analyses, reveal the Asteraceae family to be about 80 million years old and these pollen grains to be this family’s oldest fossils ever discovered. Today, Antarctica is the one continent where we cannot find daisies (or any members of the Asteraceae family), yet it is where the oldest fossils of this flowering plant family were found.
Marie Curie Fellow at RBG Kew Luis Palazzesi, says:
“Fossils finds like this are hugely important in our task to fill in the gaps of knowledge on the evolution of plants, adding a crucial calibration point to the tree of life. In the case of the Asteraceae family, we can now safely say that the oldest daisies were probably trampled by the last surviving dinosaurs – this would probably come as a great surprise to most gardeners!
"This discovery will allow us to begin to unearth how this enormous family, dominant for the past several millions of years, expanded outside of Antarctica and other gondwanan continents. It also has important implications for our understanding of pollinators, with Asteraceae regarded as one of the most influential families in both the diversification and evolution of animals such as bees, hummingbirds and wasps. Now we can begin to unlock how the Asteraceae family tree expanded.”
The fossil pollen grains which have been analysed belong to the species Tubulifloridites lilliei. Prior to this finding,the oldest fossil of Asteraceae was from the Cenozoic – the Eocene of Patagonia (47.5 million years ago) – postdating the extinction of dinosaurs.
The plant family tree gives scientists a framework for deepening our understanding of how our ecosystems function and provide a powerful tool for prediction, species discovery, monitoring and conservation. Evolutionary trees enable us to understand the evolution of not just plants, but all life on earth that depends upon plants. It is a tool for science, and humanity, ensuring we can understand the evolution of plants over time, and trace, in incredible detail, the diversity back to its simplest origins.
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Marie Curie Fellow at RBG Kew, Luis Palazzesi and RBG Kew’s Senior Research Leader, Felix Forest are available for interview.
An embargoed PDF of the paper "Early evolution of the angiosperm clade Asteraceae in the Cretaceous of Antarctica" is available from the Kew Press Office.
For more background on the Plant Family Tree you can watch the video Beyond the Gardens: The Plant Family Tree http://www.kew.org/science-conservation/plants-fungi/plant-family-tree.
This video features a variety of Kew scientists who are working on a core element of Kew’s Science Strategy –The Plant and Fungal Trees of Life
More information on the Science Strategy can be found here http://www.kew.org/science-conservation/kews-science-strategy
Notes to editors
The Royal Botanic Gardens, Kew is a world famous scientific organisation, internationally respected for its outstanding collections as well as its scientific expertise in plant diversity, conservation and sustainable development in the UK and around the world. Kew Gardens is a major international and a top London visitor attraction. Kew’s 132 hectares of landscaped gardens, and Kew’s country estate, Wakehurst, attract over 1.5 million visits every year. Kew was made a UNESCO World Heritage Site in July 2003 and celebrated its 250th anniversary in 2009. Wakehurst is home to Kew's Millennium Seed Bank, the largest wild plant seed bank in the world. Kew receives approximately just under half of its funding from Government through the Department for the Environment, Food and Rural Affairs (Defra). Further funding needed to support Kew’s vital work comes from donors, membership and commercial activity including ticket sales.
Institutions involved in the study:
Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (CONICET), Argentina
Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, UK
Laboratorio de Sistemática y Biología Evolutiva Museo de La Plata, Argentina
Centro Austral de Investigaciones Científicas, Tierra del Fuego, Argentina
Department of Palaeontology, GNS Science, New Zealand