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Evolution Of Orchids Learning From Recent Fossil Discoveries

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1 Evolution Of Orchids Learning From Recent Fossil Discoveries
Christinia Schoch

2 2011

3 2009

4 Before Orchid Fossils Freudenstein and Rasmussen (1999)
What does morphology tell us about orchid relationships? – A cladistic analysis. Compared 54 morphological characters and 103 taxa Excluded 10 previously studied characters Used Hypoxis as the outgroup Used genotype level correction (generic exemplar approach) for missing characters unless a known polymorphism was present Analyzed for shortest trees and trees with highest fitness

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6 27 – anther orientation (0=erect, 1=bend late, 2=bend early)
31 – basal caudicals (0=absent, 1=present) 32 – hammer stipe (0=absent, 1=present) 33 – tegula (0=absent, 1=present) 34 – pollen unit (0=monad, 1=tetrad) 38 – massulae (0=absent, 1=orchidoid, 2=epidendroid) 39 – pollinuim texture (0=granular, 1=solid) 40 – pollinium number: 2 (0=absent, 1=present) 41 – pollinium number: (0=absent, 1=longitudinal, 2=transverse) 42 – pollinium orientation (0=juxtaposed, 1=superposed) 44 – stigma (0=protruded, 1=sunken) 46 – viscidium (0=none, 1=diffuse, 2=detachable)

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9 The First Orchid Fossil

10 The First Orchid Fossil
Ramirez et al (2007) Dating the origin of the Orchidaceae from a fossil orchid with its pollinator. Discovered in Dominican Republic in 2000 Aged the amber as per Iturralde-Vinent (1996) at Myr Used morphological characteristics of pollinarium to identify potential taxa Compared 129 shortest trees for cladistic position Compared 25 morphological traits and 15 taxa NPRS and PL for aging lineage Genbank plastid DNA sequences for 60 genera Used Asparagales as the outgroup

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12 Flower: 3 Pollinarium: 10 Pollen (micro): 10 Pollination: 2

13 3 – anther orientation (0=erect, 1=bent)
Morphological data matrix Listera 100 001 000 0?1 00- --- 010 ?03 4 Epipactis ?00 110 ?0? Nervilia ?01 ?1? 2 Altensteinia 002 101 111 11? ? Chloraea Gomphichis 011 Ponthieva Spiranthes Zeuxine ?10 Goodyera Ludisia 112 3 Kreodanthus 0?2 ??? Microchilus 1?0 Meliorchis 3 – anther orientation (0=erect, 1=bent) 4 – basal caudicals (0=absent, 1=present) 5 – hamulus stipe (0=absent, 1=present) 9 – tegula stipe (0=absent, 1=present) 20 – pollen unit (0=monad, 1=tetrad) 14 – massulae (0=absent, 1=present) 13 – pollinuim texture (0=granular, 1=massulate) 12 – pollinium number (0=2, 1=4, 2=>4) 11 – pollinium orientation (0=juxtaposed, 1=superposed) 2 – stigma (0=protruded, 1=flat or slightly convex) 6 – viscidium (0=none, 1=diffuse, 2=detachable)

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15 Goodyera Ludisia Zeuxine Gomphicus Spiranthes Ponthiera Altensia
Epipactus Chloraea Listeria Epipactus Listera Goodyera Ludisia Zeuxine Spiranthes Gomphicis Altensteinia Ponthieva Chloraea Nervilia n/a 11 10 9 12 8 6 Nervilia

16 Molecular clock chronogram estimated via penalized likelihood using 50% Majority-Rule consensus topology of the family Orchidaceae when using the oldest bound ages of fossil calibrations. Dashed branches subtend nodes with posterior probabilities below 0.95. Circles indicate age-constrained nodes. Out = Outgroups, Apo =Apostasioideae Cyp = Cypripedioideae Orc = Orchidoideae Epi = Epidendroideae H.epi = Higher Epidendroids Goo = Goodyerineae

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18 The Oldest Orchid Fossils
Conran et al. (2009) Earliest orchid marcrofossils: Early Miocene Dendrobium and Earina (Orchidaceae: Epidendroideae) from New Zealand. Discovered in New Zealand in diatomite from a mine Aged the fossils using spore and pollen data located in surrounding sediments as per Bannister et al. (2005) Used morphological characteristics of leaves and holotype cuticles to identify potential relationships to modern species of Orchidaceae. Compared morphological characters to previously known cladograms and modern specimens of suspected genera to identify location within Orchidaceae.

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22 Using the Fossil Record
Gustafsson et al. (2010) Reassessing the temporal evolution of orchids with new fossils and a Bayesian relaxed clock, with implications for the diversification of the rare South American genus Hoffmannseggella. Used the descriptions of fossils found by Ramirez (2007) and Conran et al. (2009) to look at the age of the evolution of Orchidaceae. Compared Bayesian relaxed clock in BEAST and PL in r8s methods of estimating clade age. Compared newly aged phylogenetic tree with ancient global climate data.

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30 Summation Without fossil evidence, orchid phylogenitic trees could only be based off of morphological characteristics of modern species. Fossil evidence provided information to place extant species within the trees of Orchidaceae and age orchid phylogeny. Orchids are much older than originally thought, with a most recent common ancestor in the Late Cretaceous period. Orchid diversification began in a period of global cooling, not global warming.

31 Older Than You Thought!


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