Presentation on theme: "Did dinosaurs have lice? Vince Smith, Tom Ford, Kevin Johnson*, Paul Johnson & Rod Page University of Glasgow, Glasgow, UK *Illinois Natural History Survey,"— Presentation transcript:
Did dinosaurs have lice? Vince Smith, Tom Ford, Kevin Johnson*, Paul Johnson & Rod Page University of Glasgow, Glasgow, UK *Illinois Natural History Survey, USA
Fossil Lice Psocoptera Menacanthus / Menopon -complex Ricinidae Laemobothriidae Boopiidae Austromenopon -complex Dennyus -complex Colpocephalum -complex Collected Eckfeld maar near Eifel, Germany Middle Eocene (Middle Lutetian, 44.3±0.4 Ma) First fossil louse Completes ordinal representation of fossil insects Excellent preservation Phylogenetic affinities with modern feather lice Parasite of Anseriformes or Charadriiformes Crown group position Suggests lice are very old Points to a long coevolutionary history with birds Useful molecular calibration point Wappler, Smith & Dalgleish, Proc.R.Soc., 2004.
ii.Establish calibration points -Crown group fossils -R8s (Sanderson, 2003) iii.Apply rate smoothing -Penalized likelihood -Cross validation iv.Multiple approaches! -Bottom up -Top down - cospeciation dates v.Compare ages Bottom Up Top Down 35 ma 30 ma i.Test for molecular clock
Cospeciation Events Constraints Min. Age 44 ma Louse Fossil Combined ML 0.1 (18s, COI, EF1- ) Dove-Louse Cospeciation Age Fixed 19.8 ma Rhea/Ostrich- Louse Cospeciation Age Fixed 60 ma Primate-Louse Cospeciation Age Fixed 4.5 ma Amblycera Ischnocera Anoplura Rhyn. Louse Phylogeny (unsmoothed)
Host Implications Paleocene Cretaceous Late Cretaceous Early Cretaceous Late Jurassic 157ma ± 146ma ± 97ma ± 65ma ± Modern Birds Ratites and tinamous Neognathae Neornithes Archaeopteryx Paleognathae Tertiary big bang model for modern bird evolution sensu Feduccia, 1995 Figure adapted from Feduccia, Big bang followed by a big switch? Modern birds much older - Gondwanic origin? Revised classic model sensu Cracraft, 2001 KT Modern Birds
Summary Lice are old ( ma) Major radiation of lice before the KT (65ma) Modern birds & lice have a very long coevolutionary history Origin of lice associated with origin of feathers? Recent threopod dinosaurs probably had lice? Molecular clocks run fast at times of rapid radiation? Caveats