Sprecher
Beschreibung
Worldwide, oceanic islands are known to harbour unique floras and vegetation types. Within Macaronesian archipelagos, one of the most emblematic ecosystems are the evergreen broad-leaved Laurel forests. These were, since the mid-19th century, based on an extensive continental fossil record, considered an impoverished relict of extinct taxa that once occurred during the Cenozoic of Europe. This view was long held until recently, when molecular dating advocated a recent, i.e., Pleistocene origin of many of the plant taxa present in these insular forests. However, these contradicting biogeographical/evolutionary hypotheses (i.e., relict vs. recent) can be tested if deep-time and palaeobiologically informative fossils are found within Macaronesian Islands. Here we report, based on insular volcanostratigraphy, 40Ar-39Ar dating, and palaeobotanical data, a new Late Miocene lacustrine fossiliferous locality, the Socorridos Lagerstätte, from Madeira Island, Portugal. The fossils are morphologically and anatomically preserved as mummified/lignified leaves, flowers, anthers, fruits, seeds, wood fossils and include charcoalified woods. Leaf and flower fossils provide direct palaeoecological evidence of a Laurel forest composed by Laurus sp. and Ocotea sp. already established in the Late Miocene of Madeira Island. Furthermore, the palaeoflora includes the presence of currently endemic representatives within the families Asteraceae, Apiaceae, Boraginaceae, Brassicaceae, Lamiaceae, Campanulaceae and Ericaceae to name a few. In this talk we briefly explore the conflicting results obtained from the Socorridos fossils and phylogenetic studies, pointing to the need of the detailed study and integrative deep-time plant fossils record to fully understand the plant evolution on islands.