Anne-Marie P. Tosolini

Insect and clitellate annelid traces in mesofossil assemblages from the Cretaceous of Australasia

Mesofossil assemblages from several Cretaceous and Cenozoic units across Australia and New Zealand provide new evidence of insect and annelid behaviour. The earliest scale insects (Diaspididae, Coccoidea) from Australasia are described and represented by three scale morphotypes. The mesofossil assemblages also reveal clitellate annelid cocoon morphotypes, three morphotypes of arthropod coprolites and several insect piercement structures on gymnosperm leaf or stem fragments, possibly related to feeding or more likely oviposition. This research offers a new avenue for detecting cryptic terrestrial invertebrate groups and their interactions, particularly with plants, in the fossil record. The fossils demonstrate that insect/invertebrate activity can be preserved and identified in mesofossil suites, that such traces and exoskeleton fragments are relatively common in acid-extracted mesofossil suites, and that recognizable categories occur on multiple landmasses and at various ages.

Paleocene flora from Seymour Island, Antarctica: revision of Dusén's (1908) pteridophyte and conifer taxa

The Paleocene flora from Seymour Island, Antarctica, first collected by Nordenskjöld on the Swedish South Polar Expedition (1901–1903), was described by Dusén (1908) as having 87 leaf taxa making it one of the most diverse floras of this age in the Southern Hemisphere. The original descriptions of these leaf impressions included 37 pteridophytes and one conifer. Many species identified by Dusén were based on single fragmentary specimens. Major new collections housed at the British Antarctic Survey (Cambridge, UK), together with the original collections held at The Swedish Museum of Natural History, form the basis for a taxonomic revision of the flora. This paper concentrates on the pteridophytes and conifers. The diversity is considerably reduced from Duséns estimates with just three ferns (Cladophlebis aemulans, Cladophlebis seymourensis, Sphenopteris angustiloba) and two conifers (Araucaria imponens, Elatocladus seymourensis) recognized.

Paleocene flora from Seymour Island, Antarctica: revision of Dusén's (1908) angiosperm taxa

The Paleocene flora from Seymour Island, Antarctica, is one of the most diverse floras of this age in the Southern Hemisphere. First collected on the Swedish South Polar Expedition (1901–1903), it was described by Dusén in 1908 as having 87 leaf taxa. Forty-seven angiosperm taxa were described and/or illustrated. Many species are based on single specimens, and the flora has not been re-examined in its entirety since it was first described. This study is the first reassessment of the flora updating the original research using current methodologies, and permitting evaluation of the flora in the context of modern ideas on plant evolution and palaeogeography. This paper continues the revision of the material first studied by Dusén; a previous paper described the ferns and gymnosperms; here we describe the angiosperms. The revision is based on the original collections held at the Swedish Museum of Natural History, together with the first major new collections held at the British Antarctic Survey. Among the taxa recognized by Dusén, we recognize only three entire-margined and 11 tooth-margined angiosperms. This revision to 14 species notably lacks the two tropical elements originally described from the flora, Mollinedia seymourensis and Miconiiphyllum austral. Hence, its status as a ‘Mixed Flora’ comes into question and influences climatic interpretations based on Gondwanan floras. Anne-Marie Tosolini∗ [a.tosolini@unimelb.edu.au], Department of Earth Sciences, University of Leeds, Leeds LS2 9JT, UK, and Environmental Geoscience, Latrobe University, Victoria, 3086, Australia; David Cantrill [david.cantrill@rbg.vic.gov.au], National Herbarium of Victoria, Royal Botanic Gardens Melbourne, Private Bag 2000, Birdwood Ave, South Yarra, Victoria, 3141, Australia; Jane Francis [j.francis@earth.leeds.ac.uk], Department of Earth Sciences, University of Leeds, Leeds LS2 9JT, UK. ∗Present address: School of Earth Sciences, The University of Melbourne, Victoria 3010, Australia. Received 5.5.2012; revised 13.12.2012; accepted 7.1.2012.

EVIDENCE FOR INSECT AND ANNELID ACTIVITY ACROSS THE TRIASSIC-JURASSIC TRANSITION OF EAST GREENLAND

Abstract During a study of macroflora from the Astartekløft locality in Jameson Land, East Greenland, endophytic insect ovipositions (egg traces) belonging to ichnogenus Paleoovoidus were recorded for the first time in ginkgoalean (Ginkgoites, Sphenobaiera, and Baiera) fossil leaves across the Triassic–Jurassic (Tr–J) transition (ca. 200 Ma). The ovipositions may have been produced by insects in the order Odonata (dragonflies and damselflies) and are relatively more abundant before than after the Tr–J transition, possibly reflecting changes in plant-insect association. Fossil clitellate annelid (leech) cocoons were also discovered in a macerated sample from a single bed within the Tr–J transition. The cocoons belong to two species: Dictyothylakos pesslerae and Pilothylakos pilosus, extending the range of the latter genus from the Early Cretaceous to the Early Jurassic. This new evidence suggests that the ecosystem and food webs were profoundly affected by the environmental degradation surrounding the end-Triassic event (ETE), which was marked by faunal mass extinctions and floral turnover. Invertebrate ichno- and body fossils may add significantly to paleoenvironmental information provided by plant fossil assemblages, and therefore a protocol for recording evidence of invertebrate activity in paleobotanical research is suggested, including analyzing a standardized number of specimens for fossil traces and bulk maceration for discovery of invertebrate body fossils. More well-designed studies on Mesozoic plant-invertebrate associations are needed and will provide deeper knowledge about the structure and evolution of complex ecosystems.

Early Cretaceous polar biotas of Victoria, southeastern Australia - an overview of research to date

Poropat, S.F., Martin, S.K., Tosolini, A.-M.P., Wagstaff, B.E, Bean, L.B., Kear, B.P., Vickers-Rich, P. & Rich, T.H., May 2018. Early Cretaceous polar biotas of Victoria, southeastern Australia—an overview of research to date. Alcheringa 42, 158–230. ISSN 0311-5518. Although Cretaceous fossils (coal excluded) from Victoria, Australia, were first reported in the 1850s, it was not until the 1950s that detailed studies of these fossils were undertaken. Numerous fossil localities have been identified in Victoria since the 1960s, including the Koonwarra Fossil Bed (Strzelecki Group) near Leongatha, the Dinosaur Cove and Eric the Red West sites (Otway Group) at Cape Otway, and the Flat Rocks site (Strzelecki Group) near Cape Paterson. Systematic exploration over the past five decades has resulted in the collection of thousands of fossils representing various plants, invertebrates and vertebrates. Some of the best-preserved and most diverse Hauterivian–Barremian floral assemblages in Australia derive from outcrops of the lower Strzelecki Group in the Gippsland Basin. The slightly younger Koonwarra Fossil Bed (Aptian) is a Konservat-Lagerstätte that also preserves abundant plants, including one of the oldest known flowers. In addition, insects, crustaceans (including the only syncaridans known from Australia between the Triassic and the present), arachnids (including Australia’s only known opilione), the stratigraphically youngest xiphosurans from Australia, bryozoans, unionoid molluscs and a rich assemblage of actinopterygian fish are known from the Koonwarra Fossil Bed. The oldest known—and only Mesozoic—fossil feathers from the Australian continent constitute the only evidence for tetrapods at Koonwarra. By contrast, the Barremian–Aptian-aged deposits at the Flat Rocks site, and the Aptian–Albian-aged strata at the Dinosaur Cove and Eric the Red West sites, are all dominated by tetrapod fossils, with actinopterygians and dipnoans relatively rare. Small ornithopod (=basal neornithischian) dinosaurs are numerically common, known from four partial skeletons and a multitude of isolated bones. Aquatic meiolaniform turtles constitute another prominent faunal element, represented by numerous isolated bones and articulated carapaces and plastrons. More than 50 specimens—mostly lower jaws—evince a high diversity of mammals, including monotremes, a multituberculate and several enigmatic ausktribosphenids. Relatively minor components of these fossil assemblages are diverse theropods (including birds), rare ankylosaurs and ceratopsians, pterosaurs, non-marine plesiosaurs and a lepidosaur. In the older strata of the upper Strzelecki Group, temnospondyl amphibians—the youngest known worldwide—are a conspicuous component of the fauna, whereas crocodylomorphs appear to be present only in up-sequence deposits of the Otway Group. Invertebrates are uncommon, although decapod crustaceans and unionoid bivalves have been described. Collectively, the Early Cretaceous biota of Victoria provides insights into a unique Mesozoic high-latitude palaeoenvironment and elucidates both palaeoclimatic and palaeobiogeographic changes throughout more than 25 million years of geological time. Stephen F. Poropat*† [sporopat@swin.edu.au; stephenfporopat@gmail.com], Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Sarah K. Martin*‡ [sarah.martin@dmirs.wa.gov.au; martin.sarahk@gmail.com] Geological Survey of Western Australia, 100 Plain St, East Perth, Western Australia 6004, Australia; Anne-Marie P. Tosolini [a.tosolini@unimelb.edu.au] and Barbara E. Wagstaff [wagstaff@unimelb.edu.au] School of Earth Sciences, The University of Melbourne, Melbourne, Victoria 3010, Australia; Lynne B. Bean [lynne.bean@anu.edu.au] Research School of Earth Sciences, Australian National University, Acton, Canberra, Australian Capital Territory 2001, Australia; Benjamin P. Kear [benjamin.kear@em.uu.se] Museum of Evolution, Uppsala University, Norbyvägen 16, Uppsala SE-752 36, Sweden; Patricia Vickers-Rich§ [prich@swin.edu.au; pat.rich@monash.edu] Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Thomas H. Rich [trich@museum.vic.gov.au] Museum Victoria, PO Box 666, Melbourne, Victoria 3001, Australia. *These authors contributed equally to this work. †Also affiliated with: Australian Age of Dinosaurs Museum of Natural History, Lot 1 Dinosaur Drive, PO Box 408, Winton, Queensland 4735, Australia. ‡Also affiliated with: Earth and Planetary Sciences, Western Australian Museum, Welshpool, Western Australia 6101, Australia. §Also affiliated with: School of Earth, Atmosphere and Environment, Monash University, Melbourne, Victoria 3800, Australia.