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Tracing insular woodiness in giant Daucus (s.l.) fruit fossils from the Early Pleistocene of Madeira Island (Portugal)
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Orientador(es)
Resumo(s)
Plants on oceanic islands can evolve insular syndromes such as secondary woodiness, a generalized trend found in island
floras worldwide. This phenomenon occurs through evolution in situ. It is triggered by ecological and physiological stimuli that trans form herbaceous annuals into woody perennials. However, well-dated and informative fossils that could help track and frame the evo lution of this syndrome are lacking. Remarkably, in Madeira Island (Portugal), there are good examples of Apiaceae that evolved
secondary woodiness, like the giant neoendemic Melanoselinum (≡ Daucus). Apiaceae has a very scarce fossil record, despite being
a cosmopolitan family and an economically important crop. Here we describe the oldest Daucus s.l. fossil known to date and the first
fossil evidence of a plant with insular woodiness. The fossils are preserved as mummified/compressed mericarps within 1.3-million year-old fluvio-lacustrine sediments of the Funchal unit, Upper Volcanic complex, near Porto da Cruz. We assign them to the extant
neoendemic species Melanoselinum (≡ Daucus) decipiens. The mericarp morphology shows remarkable stasis since the Calabrian stage
of the Early Pleistocene. Our results demonstrate that in the Madeiran Daucinae clade, insular woodiness developed at least 1.3 million
years ago, indicating a coeval or earlier immigration to Madeira Island of a Daucus sp. Our results reinforce the role of palaeobotanical
research in oceanic islands, supported by stratigraphy and geochronology studies, as a key element for the understanding of plant
palaeobiogeography, ecology and evolution worldwide. We expect this contribution to shed light on the evolutionary origins of carrots,
and related plant groups, an important element of human food, and to better comprehend the evolution of plant insular woodiness.
Descrição
Palavras-chave
Island syndromes Macaronesia Melanoselinum Neoendemic Palaeobotany Palaeocarpology . Faculdade de Ciências da Vida
Contexto Educativo
Citação
Editora
International Association for Plant Taxonomy