Calcareous Tubeworms as Disaster Forms After the End-Permian Mass Extinction in South China

Microconchid-dominated cobbles from the Upper Devonian of Russia: Opportunism and dominance in a restricted environment following the Frasnian–Famennian biotic crisis

“…Some peculiar groups of helically-uncoiled microconchids even constructed small bioherms (e.g., Salter, 1863;Wilson et al, 2011). Recently it has been discovered that microconchids were strongly dominant encrusters in the immediate aftermath of the profound end-Permian mass extinction (see Fraiser, 2011;He et al, 2012), and one of the dominant encrusters colonizing brachiopod shells after the Frasnian-Famennian (F-F) biotic crisis (Zatoń and Krawczyński, 2011b;Zatoń and Borszcz, 2013).…”

Microconchids of the species Microconchus valvatus (Münster in Goldfuss, 1831) from the Upper Muschelkalk (Middle Triassic) of Germany

“…Vinn and Taylor 2007;Zatoń and Taylor 2009;Wilson 2010, 2012;Caruso and Tomescu 2012;He et al 2012). Therefore, they are most commonly found in situ attached to substrates which makes them valuable objects in palaeoecological investigations (Taylor and Wilson 2003).…”

“…The two latter species are also not asociated with M. valvatus in the same deposits, indicating that they were intolerant of normal marine environments. There is a growing evidence (Fraiser 2011;He et al 2012), that microconchids were the only encrusters inhabiting the harsh, post-extinction hard and firm substrate environments during the earliest Triassic and, along with the bivalve Placunopsis (see Pruss et al 2007), were dominant hard substrate organisms later on in the Spathian (Zatoń et al 2013). Even in the Middle Triassic, when environments and biotas had fully recovered to pre-extintion conditions, microconchids, along with Placunopsis bivalves, were still important encrusters, as demonstrated here.…”

“…Triassic microconchids, although very common in different palaeoenvironments (e.g. Wanner 1921;Brönnimann and Zaninetti 1972;Peryt 1974;Ball 1980;Kietzke 1989;Nützel and Schulbert 2005;McGowan et al 2009;Hagdorn 2010;Fraiser 2011;He et al 2012), have rarely been investigated with respect to taxonomic affinity. They were either traditionally treated as Spirorbis or provisionally as the microconchid genus Microconchus (e.g.…”

Permian–Triassic boundary microbialites (PTBMs) in southwest China: implications for paleoenvironment reconstruction

“…The models for their generation consist of a series of viewpoints, including: (1) reduced benthic grazing pressure; (2) upwelling of anoxic alkaline waters; (3) elimination of skeletal CaCO 3 sinks; (4) increased nutrient levels from erupted volcanic ash; and (5) a rebound in carbonate saturation following a transient ocean acidification event (Lehrmann et al 2015 and references therein). The upwelling model, in particular, has been applied by numerous workers in the Early Triassic (Kershaw et al 1999;Ezaki et al 2003;Lehrmann et al 2003;Pruss and Bottjer 2004;Pruss et al 2005;Kershaw et al 2007Kershaw et al , 2009Kershaw et al , 2011Ezaki et al 2008;Mary and Woods 2008;Mata and Bottjer 2011;He et al 2013;Woods 2014). Lehrmann et al (2003) also drew attention to the possibility of PTBM formation in oxygenated seawater conditions.…”