Diversity of feeding and pollination strategies of Mesozoic beetles Dissertation zur Erlangung des Doktorgrades (Dr. rer. nat.) der Mathematisch-Naturwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn im Promotionsprogramm Geoscience des Institutes für Geowissenschaften vorgelegt von Tong Bao aus Shandong, China Bonn, 2020 Angefertigt mit Genehmigung der Mathematich-Naturwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn 1. Gutachter: Prof. Dr. Jes Rust 2. Gutachter: Prof. Dr. Thomas Martin Tag der Promotion: 16. Juli 2020 Erscheinungsjahr: 2020 Contents Summary ······················································································································································· 1 1. Introduction ·············································································································································· 3 1.1 The Mesozoic Era ·············································································································································· 3 1.2 Beetles as the most successful animals ········································································································· 5 1.3 Mesozoic beetles ················································································································································ 7 1.4 The insect-plant interaction····························································································································· 9 1.5 The rise of “Abominable Mystery” ············································································································· 13 2. Aim of study ············································································································································ 16 2.1 The key to answering “Abominable Mystery” ·························································································· 16 2.2 The possible beetle ecology shift while the flourish of angiosperms ··················································· 18 2.3 Ecology of tropical amber forest in the Cretaceous ················································································ 19 3. Geology setting of fossil Lagerstätten ································································································· 20 3.1 Karabastau Formation ··································································································································· 21 3.2 Daohugou biota and Yixian Formation ······································································································ 22 3.3 Burmese amber (“Kachin amber”) ············································································································· 24 3.4 Baltic amber ······················································································································································ 25 3.5 Dominican amber ············································································································································ 26 4. Material and methods···························································································································· 29 4.1 Investigated specimens ··································································································································· 29 4.2 Preparation, microscopy and imaging ······································································································· 30 4.2.1 Lab preparation ······································································································································· 30 4.2.2 Optical photomicrography ···················································································································· 32 4.2.3 Confocal laser scanning microscopy ·································································································· 33 4.2.4 X-ray micro-computed tomography ··································································································· 33 4.2.5 Synchrotron X-ray microtomography ································································································ 34 4.3 Permanent storage··········································································································································· 36 5. Systematic palaeontology ······················································································································ 37 6. Discussion ················································································································································ 96 6.1 Mordellidae and Mesozoic Tenebrionoidea ······························································································ 96 6.2 Beetle-angiosperm associations ················································································································ 101 6.3 Beetle-gymnosperm association ················································································································ 106 6.4 Other beetle ecology in Cretaceous amber (fern association, scavenger, fungivorous, wood- borer, algae eater) ··············································································································································· 108 6.5 The tropical amber forest ecosystem in Cretaceous············································································· 110 7. Conclusions ··········································································································································· 112 8. Outlook ·················································································································································· 113 8.1 Taxonomy and phylogeny study ················································································································ 113 8.2 Detail study of geological background of amber deposit ··································································· 114 8.3 Cretaceous macroecology study················································································································ 114 8.4 The comparative study Cretaceous island-continental environments ·············································· 114 Acknowledgement ···································································································································· 116 References ·················································································································································· 118 Declaration about personal contributions to the papers included in this thesis ···························· 143 Appendices 1-6. ········································································································································· 146 Appendix 7.················································································································································ 188 Summary Beetles (order: Coleoptera) as the most diverse and successful animals on the earth, comprise about 400,000 species, constituting almost 40% of described insects and a quarter of all animal species. Beetles are normally recognized by their typical hard exoskeleton including the elytra. They are distributed in almost every terrestrial natural habitat today, with various feeding preferences. Approximately 90% of the species in Coleoptera emerged in the Mesozoic, especially during the Jurassic– Cretaceous period. At the same time, vegetation type on the earth was shifting significantly — angiosperms (flowering plants) rapidly replacing the dominating gymnosperms, an event which Charles Darwin called the “Abominable Mystery”. The dramatic environmental and nutritional change could have impacted the interaction between beetles and related plant groups. The evolution of beetles may have also influenced the angiosperm radiation, e.g. through zoophilous pollination. The studies in this thesis demonstrate the remarkable feeding strategies and ecological diversity of Mesozoic beetles. Fourteen species of seven families from Karabastau Formation, Daohugou Biota, Burmese amber and Baltic amber are described, ranging from Early Jurassic to Eocene. The co-evolution between beetles and vegetation environments is discussed. Based on the continuous fossil records of the family Mordellidae, the early evolution trend of a typical beetle-flower ecology is outlined. Hypothetically, insect pollination contributes largely to the diversity of flowering plants, and is essential to the Cretaceous radiation of angiosperms. Angimordella burmitina Bao, 2019 and the associated tricolpate pollens provides direct evidence of insect pollination of Cretaceous eudicots ~99 million years ago, extending the record of insect mediated angiosperm pollination at least 50 million years earlier. The great angiosperm radiation in mid-Cretaceous acted as a driving force for the replacement of earth surface vegetation. By this time, nutrition groups as gymnosperms, fern, are also changed relatively, which also imply the associated 1 beetle taxa. Praezolodinus pilosus and Cretoptomaphagus microsoma provide rare records of bottom forest