Exceptionally preserved lacustrine ostracods from the Middle Miocene of Antarctica: implications for high-latitude palaeoenvironment at 77° south

Abstract

A newly discovered Konservat-Lagerstätte from the Middle Miocene of the western Olympus Range, Dry Valleys, Antarctica, yields cypridoidean ostracods complete with preserved body and appendages. This is the first record of three-dimensionally fossilized animal soft tissues from the continent. The ostracods are preserved in goethite, secondary after pyrite, representing a novel mode of exceptional preservation. They signal a high-latitude (greater than 77° south) lake setting (Palaeolake Boreas) viable for benthic animal colonization prior to 14 Myr ago. Their presence supports the notion of warmer, tundra-like environmental conditions persisting in the Dry Valleys until the Middle Miocene.

Antarctic Ice Sheet response to a long warm interval across Marine Isotope Stage 31: A cross-latitudinal study of iceberg-rafted debris

“…Furthermore, results from both the modeling and this study agree with recent observations and estimates of current AIS mass balance (Zwally and Giovinetto, 2011;Pritchard et al, 2009), which demonstrate the heterogeneous behavior of the AIS at present. Finally, our results agree with the conclusions of Williams et al (2010), who also found that over the late Miocene-Early Pliocene, the EAIS showed a heterogeneous response to climate changes.…”

“…In spite of these large fluctuations of the EAIS margins, however, other recent studies have shown that the central portion of the EAIS has been relatively stable through at least the last 14 Ma (see review by Siegert et al, 2008). For example, the discovery of fossils in an excellent state of preservation after ∼14 Ma at or near the surface in the McMurdo Dry Valleys region demonstrates the persistence of polar desert conditions and also of relatively stable EAIS volume throughout this timespan Williams et al, 2008). It is in this context that our study hopes to contribute to an understanding of the potentially complex responses of the AIS, and particularly the EAIS, to major climate changes.…”

“…For example, Naish et al (2009) conclude that the WAIS has fluctuated greatly, and has even collapsed at times, including during the Plio-Pleistocene. Seismic and stratigraphic evidence from the Ross Sea, Wilkes Land margin, and the Prydz Bay region indicate many large-scale advances and retreats of EAIS margins since the Miocene, including during the Pliocene to Recent (Passchier et al, 2003;Escutia et al, 2005;Villa et al, 2008;Naish et al, 2009;Williams et al, 2010;Passchier, 2011). In spite of these large fluctuations of the EAIS margins, however, other recent studies have shown that the central portion of the EAIS has been relatively stable through at least the last 14 Ma (see review by Siegert et al, 2008).…”

Paleolimnological inferences based on Oligocene ostracods (Crustacea: Ostracoda) from Tremembé Formation, Southeast Brazil

“…nov. have carapaces slightly open. This pattern, also recorded by Bate (1972), Smith (2000, Williams et al (2008), Wilkinson et al (2010), Matzke-Karasz et al (2013) and Thomé et al (2014) in fossil non-marine assemblages, is possibly a taphonomic signature of lacustrine deposits.…”

Subcellular preservation in giant ostracod sperm from an early Miocene cave deposit in Australia

“…The rare occasions that 'soft-parts', i.e. appendages and internal body, are fossilized can reveal exquisite detail and provide unparalleled data on the evolution of the group [7][8][9][10][11][12][13][14][15]. For example, preserved Zenker organs, which are muscular-chitinous pumps used to transfer giant sperm to females [16] (figure 1c), in Cretaceous ostracods have been used as indirect evidence that giant sperm are a long-lived trait in the group [9].…”