Sauquet, Hervé , Cantrill, David J. , Weston, Peter H. , Barker, Nigel , Mast, Austin , Savolainen, Vincent .
Bringing together the living and the dead: Integrating extant and fossil biodiversity in evolutionary studies of Proteaceae (Proteales).
Family Proteaceae comprise 80 genera and over 1700 species of mostly woody angiosperms from a wide range of temperate and tropical habitats in the Southern Hemisphere. With a particularly rich fossil record throughout southern Gondwana extending back to the mid-Cretaceous, they represent an ideal model to test biogeographic hypotheses, in particular with respect to the origin of biodiversity hotspots with a Mediterranean climate. Here we summarize the results of a family-wide survey of morphological variation across the extant Proteaceae. Over 100 characters are evaluated and optimized onto a supertree of phylogenetic relationships within Proteaceae, constructed from several multi-locus molecular analyses. With respect to pollen morphology, this study highlights the phylogenetic potential of ultrastructural characters in Proteaceae and high levels of homoplasy and polymorphism in other characters including pollen shape and tectum sculptural patterns. In particular, the presence of abundant endexine in the apertural region coincides with the emergence of Grevilleoideae, the largest subfamily of Proteaceae, in contrast with a distinct plesiomorphic type observed in Persoonioideae and Proteoideae. This framework of morphological evolution is used to re-assess the affinities of selected macro- and microfossils that have been assigned to the Proteaceae. In cases such as the fossil inflorescences of Musgraveinanthus, we confirm that a unique combination of apomorphies allows narrowing down the possibilities to a small clade nested in the family. Conversely, we demonstrate that leaf impressions described as Lomatia and several palynomorphs assigned to specific extant genera may in fact be compatible with multiple alternative, equally parsimonious placements on the phylogeny. These results are essential to discriminate among multiple uses that may be made of the fossil record, where only very few fossil taxa are suitable to calibrate molecular dating analyses while the rest holds great potential to corroborate biogeographic scenarios drawn from other sources.
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1 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, TW9 3DS, United Kingdom
2 - Royal Botanic Gardens, Melbourne, National Herbarium of Victoria, Private Bag 2000, South Yarra, Victoria, 3141, Australia
3 - Royal Botanic Gardens, Mrs Macquaries Road, Sydney, New South Wales, 2000, Australia
4 - Rhodes University, Department of Botany, Molecular Ecology & Systematics Group, Grahamstown, Eastern Cape, 6140, South Africa
5 - Florida State University, Department of Biological Sciences, Tallahasse, Florida, 32306-1100, USA
6 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Molecular Systematics Section, Richmond, Surrey, TW9 3DS, United Kingdom
Presentation Type: Oral Paper:Papers for Sections
Location: Williford A/Hilton
Date: Monday, July 9th, 2007
Time: 11:30 AM