Early Triassic disaster and opportunistic foraminifers in South China

Abstract

Survival and recovery are important dynamic processes of biotic evolution 15 during major geological transitions. Disaster and opportunistic taxa are two significant 16 groups that dominate the ecosystem in the aftermath of mass extinction events. Disaster 17 taxa appear immediately after such crises whilst opportunists predate the crisis but also 18 bloom in the aftermath. This paper documents three disaster foraminiferal species and 19 seven opportunistic foraminiferal species from Lower Triassic successions of South China. 20They are characterized by extreme high-abundance and low-diversity and occurred 21 occasionally in the Griesbachian, Smithian, and Spathian. The characteristics (small size, 22 simple morphology) and stratigraphic ranges of these groups suggest that r-selection is a 23 commonly used strategy for survivors to cope with either harsh post-extinction conditions 24 and/or environments lacking incumbents. 25

Boreal earliest Triassic biotas elucidate globally depauperate hard substrate communities after the end-Permian mass extinction

“…Their specimens included spiral and helically uncoiled forms resembling Microconchus utahensis , Helicoconchus elongatus , and M. aberrans respectively. Compatible structural diversification thus seems to have occurred in both the Boreal-Panthalassan and Tethyan realms, where microconchids paralleled stromatolites55, inarticulate brachiopods56, Claraia bivalves4557 and various foraminiferans58 as opportunistic occupiers of benthic marine ecospace in the earliest Triassic333435. By the Spathian (late Olenekian), however, bivalves and foraminiferans, together with boring suspension-feeders3359 had colonised hard substrates to create transient metazoan reefs; these established on multi-taxic sponge60 and bivalve61 frameworks during the Smithian–Spathian “coral gap”101160.…”

Middle Phanerozoic mass extinctions and a tribute to the work of Professor Tony Hallam

“…There are currently three distinct viewpoints: The Early Triassic world was a harsh one that inhibited the recovery of all but a few hardy groups (Hallam's original idea). The recognition of extremely hot conditions at this time (Sun et al 2012), alongside the widespread anoxia, adds credence to this stance as do studies of the recovery record in South China (Song et al 2015, this issue). The Early Triassic world was normal but the preceding extinction had caused such devastation that it took a long time for the biota to even start to recover. This viewpoint can be traced back to a highly influential paper by Schubert & Bottjer (1992).…”

“…The Early Triassic world was a harsh one that inhibited the recovery of all but a few hardy groups (Hallam's original idea). The recognition of extremely hot conditions at this time (Sun et al 2012), alongside the widespread anoxia, adds credence to this stance as do studies of the recovery record in South China (Song et al 2015, this issue).…”

The Permian–Triassic boundary Lung Cam expanded section, Vietnam, as a high-resolution proxy for the GSSP at Meishan, China

“…and Geinitzina sp. (Angiolini et al 2010;Krainer & Vachard, 2011;Nestell et al 2015;Song et al 2016;Kolar-Jurkovšek et al 2018;Sudar et al 2018). In the Lung Pu section, the extinction of most foraminiferal genera appears to be sudden, as can be seen in Figure 7.…”