title: Middle Devonian liverwort herbivory and antiherbivore defence.
abstract: To test the extent of herbivory in early terrestrial ecosystems, we examined compression-impression specimens of the late Middle Devonian liverwort Metzgeriothallus sharonae, from the Catskill Delta deposit of eastern New York state. Shale fragments of field-collected specimens were processed by applying liquid nitrocellulose on exposed surfaces. After drying, the film coatings were lifted off and mounted on microscope slides for photography. Unprocessed fragments were photographed under cedarwood oil for enhanced contrast. An extensive repertoire of arthropodan-mediated herbivory was documented, representing three functional feeding groups and nine subordinate plant-arthropod damage types (DTs). The herbivory is the earliest occurrence of external foliage-feeding and galling in the terrestrial fossil record. Our evidence indicates that thallus oil body cells, similar to the terpenoid-containing oil bodies of modern liverworts, were probably involved in the chemical defence of M. sharonae against arthropod herbivores. Based on damage patterns of terrestrial plants and an accompanying but sparse body-fossil record, Devonian arthropodan herbivores were significantly smaller compared to those of the later Palaeozoic. These data collectively suggest that a broad spectrum herbivory may have had a more important role in early terrestrial ecosystems than previously thought.
authors.affiliation: Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013, USA.|Department of Entomology and BEES Program, University of Maryland, College Park, MD, 20742, USA.
authors.forename: Conrad C
authors.initials: CC
authors.lastname: Labandeira
authors.affiliation: Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Tremblay
authors.affiliation: New York State Museum, Madison Avenue, Albany, NY, 12230, USA.
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Bartowski
authors.affiliation: New York State Museum, Madison Avenue, Albany, NY, 12230, USA.
authors.forename: Linda
authors.initials: L
authors.lastname: VanAller Hernick
mesh_terms: D000818:Animals; D001181:Arthropods / Q000502:physiology; D005580:Fossils; D005843:Geography; D035926:Hepatophyta / Q000502:physiology*; D060434:Herbivory / Q000502:physiology*; D009518:New York; D018515:Plant Leaves / Q000502:physiology; D013997:Time Factors
keywords: Metzgeriothallus; New York state; arthropod; external foliage feeding; galling; herbivore; oil body cells; piercing-and-sucking