Fossil weevils (Coleoptera: Curculionidae) from latitude 85°S Antarctica

Abstract

Two species of fossil listroderine weevils (Coleoptera: Curculionidae: Rhytirhinini: Listroderina) are reported from the Meyer Desert Formation at a locality on the Beardmore Glacier in the Transantarctic Mountains about 500 km from the South Pole. Associated fossils include wood, leaves and pollen of Nothofagus, stems and leaves of several species of mosses, achenes of Ranunculus, shells of freshwater molluscs and a fish tooth. The age of the fossiliferous strata is contentious but probably within the range of Pliocene to mid-Miocene. The fossils represent organisms that colonised the margins of a glacier at the head of a fjord during an interglaciation. The autecology of the listroderine species indicates that temperatures during summer months averaged 5 ‡C. The mean annual temperature, with winter temperatures constrained by 6 months of darkness, is estimated to have been about 38 ‡C compared to the 326 ‡C estimated for sea level at latitude 85 ‡S today. The closest evolutionary link of the fossil listroderines is with South American rather than Australian or New Zealand taxa. Divergence of the taxa, at least at the level of tribe, had most probably occurred on Gondwana before the continent broke apart. The fossil species are considered to be the descendants of Antarctic lineages which evolved on the continent in the Late Cretaceous or Palaeogene and survived until the Neogene. Extinction of the listroderines and most other Antarctic terrestrial biota occurred with the growth of the polar ice sheets and the change to the polar desert climate. ß

Major middle Miocene global climate change: Evidence from East Antarctica and the Transantarctic Mountains

“…Fossil assemblages of tundra plants and animals interbedded between diamictites indicate that mean summer temperatures had to be at least 4-5 °C for two to three months of the year and MATs in the range of -8 to -12 °C (Francis and Hill, 1996;Ashworth and Thompson, 2003;Ashworth and Preece, 2003;Ashworth and Kuschel, 2003;Ashworth and Cantrill, 2004). These values are similar to the estimates of paleotemperature that resulted in wet-based glaciation and extensive surfacemelting ablation zones in the western Olympus Range.…”

Island evolutionary biogeography: analysis of the weevils (Coleoptera: Curculionidae) of the Falkland Islands (Islas Malvinas)

“…Cenocrons can be identified by considering temporal information provided by fossils and molecular clocks (Morrone, 2009). For this step of the analysis, I considered fossil information (Birnie & Roberts, 1986; Buckland & Hammond, 1997; Ashworth & Kuschel, 2003) and the molecular clock provided by Papadopoulou et al. (2009).…”

Age and uplift rates of Sirius Group sediments in the Dominion Range, Antarctica, from surface exposure dating and geomorphology

“…Mercer, 1986;McKelvey et al, 1991). Subsequent studies documenting fossil insects, fish, mollusks and paleosols within these sediments have reinforced the picture of dramatic variations between polar and more temperate conditions during deposition of the Sirius Group in the Dominion Range (Retallack et al, 2001;Ashworth and Kuschel, 2003;Ashworth and Preece, 2003). The stratigraphic age of the reworked diatoms has been confirmed by 40 Ar/ 39 Ar dating of volcanic ash in a marine core from McMurdo Sound (Barrett et al, 1992).…”