Abstract Detail

Paleobotany

Schoenenberger, Juerg [1], von Balthazar, Maria [2], López Martínez, Andrea [3], Albert, Béatrice [4], Prieu, Charlotte [5], Magallon, Susana [6], Sauquet, Hervé [7].

Placement of fossil flowers using angiosperm-wide phylogenetic analyses: proof of concept and challenges along the way forward.

The fossil record of angiosperms has increased substantially in size and quality in recent decades and has provided important new information about the antiquity of different floral morphologies and different phylogenetic lineages. What has not kept pace with these recent advances is our ability to test the systematic placement of fossils based on phylogenetic analyses, mainly due to the lack of adequate morphological datasets for extant taxa. We propose a new approach centered on a multi-user database (PROTEUS) and an angiosperm-wide floral dataset for 792 extant species representing all orders and 372 families (89%) of angiosperms, which we have recently used to infer ancestral flowers across the angiosperm tree. For the present study, we have supplemented the original data set with additional floral and pollen traits, now adding up to a total of 30 characters. To demonstrate the potential of the present Paleo-eFLOWER initiative, we scored 10 published Cretaceous flowers for the same set of characters and present results of a molecular backbone approach to evaluate the phylogenetic position of the fossils. Our main long term goals with the inclusion of fossil taxa into our data set are: (i) to develop a tool for the paleobotanical community to systematically test the phylogenetic position of fossil flowers in an angiosperm-wide context, (ii) to test the impact of fossils on phylogenetic relationships (of extant taxa), and (iii) to incorporate the fossil record into the reconstruction of trait evolution. For this presentation, we focus on our first goal. We find that some fossils are placed congruently with earlier hypotheses, while others are found in positions that had not been suggested previously. A few of them take up equivocal positions, including the stem branches of large clades. Possible reasons for equivocal results include the lack of distinct combinations of apomorphic characters as well as the still limited sampling of extant species in our current data set. Although further work is needed, these first results are promising. We expect that such angiosperm-wide analyses will in many cases only provide a coarse estimate of the phylogenetic position of a fossil taxon and will need to be followed by finer-scale analyses. However, in our view, this is a crucial step forward in our attempts to integrate knowledge of extant and extinct angiosperms as it makes possible unbiased and reproducible tests on the phylogenetic position of fossil flowers.

Related Links:
eFLOWER: A framework for understanding the evolution and diversification of flowers

1 - University Of Vienna, Department Of Botany And Biodiversity Research, Rennweg 14, Vienna, AT-1030, Austria
2 - Department Of Botany And Biodiversity Research, Division Of Systematic And Evolutionary Botany, Rennweg 14, Vienna, A-1030, Austria
3 - Universidad Nacional Autónoma de México, Instituto de Biología, Circuito Exterior, Ciudad Universitaria, Coyoacán, Mexico City, 04510, Mexico
4 - Université Paris-Sud, Laboratoire Écologie, Systématique, Évolution, Bat 360 Rue Du Doyen Guinet, Orsay, 91405, France
5 - Université de Versailles Saint-Quentin-en-Yvelines, UFR des Sciences, 45 avenue des Etats Unis, Versailles, 78035, France
6 - Universidad Nacional Autonoma De Mexico, Instituto De Biologia, 3er Circuito De Ciudad Universitaria, Del. Coyoacan, A.p. 70-233, Mexico City, Mexico D.F., DIF, 04510, Mexico
7 - Royal Botanic Gardens and Domain Trust, National Herbarium of New South Wales (NSW), Mrs Macquaries Rd, Sydney, Sydney, NSW 2000, Australia

Keywords:
Angiosperms
floral structure
fossil flowers
eFLOWER
phylogenetic analysis.

Presentation Type: Oral Paper
Session: PAL3, Paleobotany III: Mesozoic Paleobotany
Location: Tucson C/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 2:30 PM
Number: PAL3005
Abstract ID:351
Candidate for Awards:None