Mass extinction, gradual cooling, or rapid radiation? Reconstructing the spatiotemporal evolution of the ancient Angiosperm genus Hedyosmum (Chloranthaceae) Using empirical and simulated approaches
Chloranthaceae is a small family of flowering plants (65 species) with an extensive fossil record extending back to the Early Cretaceous. Within Chloranthaceae, Hedyosmum is remarkable because of its disjunct distribution – one species in the Paleotropics and 44 confined to the Neotropics – and a lo...
| Autores: | , |
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| Formato: | artículo |
| Fecha de publicación: | 2011 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/34829 |
| Acesso em linha: | http://hdl.handle.net/10261/34829 |
| Access Level: | acceso abierto |
| Palavra-chave: | Chloranthaceae Hedyosmum Biogeography Neotropics diversification Andean uplift high extinction incomplete taxon sampling |
| Resumo: | Chloranthaceae is a small family of flowering plants (65 species) with an extensive fossil record extending back to the Early Cretaceous. Within Chloranthaceae, Hedyosmum is remarkable because of its disjunct distribution – one species in the Paleotropics and 44 confined to the Neotropics – and a long “temporal gap” between its stem age (Early Cretaceous) and the beginning of the extant radiation (late Cenozoic). Is this gap real, reflecting low diversification and a recent radiation, or the signature of extinction? Here we use paleontological data, relaxed clock molecular dating, diversification analyses, and parametric ancestral area reconstruction to investigate the timing, tempo, and mode of diversification in Hedyosmum. Our results, based on analyses of plastid and nuclear sequences for 40 species, suggest that the ancestor of Chloranthaceae and the Hedyosmum stem lineages were widespread in the Holarctic in the Late Cretaceous. High extinction rates, possibly associated with Cenozoic climatic fluctuations, may have been responsible for the low extant diversity of the family. Crown group Hedyosmum originated c. 36 – 43 Ma and colonized South America from the north during the Early-Middle Miocene (c. 20 Ma). This coincided with an increase in diversification rates, probably triggered by the uplift of the northern Andes from the Mid-Miocene onwards. This study illustrates the advantages of combining paleontological, phylogenetic, and biogeographic data to reconstruct the spatiotemporal evolution of an ancient lineage, for which the extant diversity is only a remnant of past radiations. It also shows the difficulties of inferring patterns of lineage diversification when incomplete taxon sampling is combined with high extinction rates. |
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