125 research outputs found

    Forest-Tundra Neighbouring the North Pole: Plant and Insect Remains from the Plio-Pleistocene Kap København Formation, North Greenland

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    The Kap Kobenhavn Formation in northeast Peary Land, Greenland, is believed to be 2.0-2.5 million years old, i.e., from the Plio-Pleistocene transition. The dating is primarily based on biostratigraphical correlation of lower marine fauna and a few fragments of terrestrial mammals. Although deposited in marine and coastal environments, the sediments contain abundant remains of terrestrial and limnic organisms. This paper examines macroscopic plant and insect remains. About 60 taxa of vascular plants and 120 insect taxa have so far been identified. Nearly all of the named insect species are extant, extralimital forms, generally of a recent subarctic/boreal and more or less circumpolar distribution. The species composition shows that upland areas were covered with forest-tundra and heathland and that mesotrophic, well-vegetated lakes and a number of other wetland localties existed in the area. The presence of arctic plants in the formation puts some time constraints on their origin.

    Paleontology of leaf beetles

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    `The rate of evolution in any large group is not uniform; there are periods of relatise stability, and periods of comparatively rapid change.' Cockerell and LeVeque, 1931 To Yenli Ych, my beloved wife, a most wonderful person! The fossil record of the Chrysomelidae can be tentatively traced back to the late Paleozoic to early Mesozoic Triassic. Mesozoic records at least 9 subfamilies, 19 genera, and 35 species, are represented by the Sagrinae, the exclusively Mesozoic Proto scelinae, Clytrinae, Cryptocephalinae, Eumolpinae, Chrysomelinae. Galerucinac, Alticinae, and Cassidinae. Cenozoic records at least 12 subfamilies- 63 % of the extant- 12! genera, and 325 species, include the same extant subfamilies as well as the Donaciinae, Zeugophorinae, Criocerinae, and Hispinae and can be frequently identified to genus, especially if preserved in amber. Quaternary records are often identified to extant species. tn total, at least t3! genera about 4 % of total extant, and 357 species < 1 % have been reported. At least, 24 genera <1 % of the extant seem to be extinct. Although reliable biological information associated with the fossil chrysomelids is very scarce, it seems that most of the modern host-plant associations were established, at least, in the late Mesozoic to early Cenozoic. As a whole, stasis seems to be the general rule of the chrysomelid fossil record. Together with other faunal elements, chrysomelids, especially donaciines, have been used as biogeographic and paleoclimatological indicators in the Holocene. I

    Changes to the Fossil Record of Insects through Fifteen Years of Discovery

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    The first and last occurrences of hexapod families in the fossil record are compiled from publications up to end-2009. The major features of these data are compared with those of previous datasets (1993 and 1994). About a third of families (>400) are new to the fossil record since 1994, over half of the earlier, existing families have experienced changes in their known stratigraphic range and only about ten percent have unchanged ranges. Despite these significant additions to knowledge, the broad pattern of described richness through time remains similar, with described richness increasing steadily through geological history and a shift in dominant taxa, from Palaeoptera and Polyneoptera to Paraneoptera and Holometabola, after the Palaeozoic. However, after detrending, described richness is not well correlated with the earlier datasets, indicating significant changes in shorter-term patterns. There is reduced Palaeozoic richness, peaking at a different time, and a less pronounced Permian decline. A pronounced Triassic peak and decline is shown, and the plateau from the mid Early Cretaceous to the end of the period remains, albeit at substantially higher richness compared to earlier datasets. Origination and extinction rates are broadly similar to before, with a broad decline in both through time but episodic peaks, including end-Permian turnover. Origination more consistently exceeds extinction compared to previous datasets and exceptions are mainly in the Palaeozoic. These changes suggest that some inferences about causal mechanisms in insect macroevolution are likely to differ as well

    Holocene insect remains from south-western Greenland

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    Remains of plants and invertebrates from Holocene deposits in south-western Greenland include a number of insect fragments from Heteroptera and Coleoptera. Some of the finds extend the known temporal range of the species considerably back in time, and one of the taxa has not previously been found in Greenland either fossil or extant. The fossil fauna includes the weevil Rutidosoma globulus which is at present extremely rare in Greenland. Its rarity might indicate that it is a recent immigrant, but the fossil finds provide a minimum date for its arrival at around 5840 cal. years B.P. Other remains of terrestrial insects complement the scarce fossil Greenland record of the species concerned
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