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

Abstract

The end-Permian mass extinction constituted the most devastating biotic crisis of the Phanerozoic. Its aftermath was characterized by harsh marine conditions incorporating volcanically induced oceanic warming, widespread anoxia and acidification. Bio-productivity accordingly experienced marked fluctuations. In particular, low palaeolatitude hard substrate communities from shallow seas fringing Western Pangaea and the Tethyan Realm were extremely impoverished, being dominated by monogeneric colonies of filter-feeding microconchid tubeworms. Here we present the first equivalent field data for Boreal hard substrate assemblages from the earliest Triassic (Induan) of East Greenland. This region bordered a discrete bio-realm situated at mid-high palaeolatitude (>30°N). Nevertheless, hard substrate biotas were compositionally identical to those from elsewhere, with microconchids encrusting Claraia bivalves and algal buildups on the sea floor. Biostratigraphical correlation further shows that Boreal microconchids underwent progressive tube modification and unique taxic diversification concordant with changing habitats over time. We interpret this as a post-extinction recovery and adaptive radiation sequence that mirrored coeval subequatorial faunas, and thus confirms hard substrate ecosystem depletion as a hallmark of the earliest Triassic interval globally.

Temporal dynamics of encrusting communities during the Late Devonian: a case study from the Central Devonian Field, Russia

“…3). The present data are consistent with previous studies indicating that this opportunistic group of encrusters flourished and became more abundant than other encrusters in the aftermaths of mass extinctions and biotic crises (Fraiser 2011; Zatoń and Krawczyński 2011; He et al 2012; Yang et al 2015; Zatoń et al 2016).…”

Microconchus cravenensisn. sp.: a giant among microconchid tubeworms

“…Such a niche could have been advantageous (see Vinn, 2010a), providing protection against overgrowth and sediment covering, and lessening competition for suspended food in a higher tier. The microconchids in this setting had the ability to keep pace with the growth of encrusting algae and microbialite with which they were typically associated (e.g., Peryt, 1974;Burchette and Riding, 1977;Dreesen and Jux, 1995;Zatońet al, 2016b). Only such a growth mode allowed microconchids to develop primary frameworks (Vinn, 2010a).…”

“…Although the majority of microconchids were characterized by Spirorbis -like, planispirally coiled tubes, several genera produced unique morphologies. For example, some Carboniferous (Mississippian) species formed long, helically uncoiled tubes (e.g., Burchette and Riding, 1977), whereas the Lower Triassic Spathioconchus Zatoń et al, 2016b formed straight, trumpet-like tubes (Zatoń et al, 2016b) and the Permian Helicoconchus Wilson, Vinn, and Yancey, 2011 had long, helically uncoiled tubes that showed budding (Wilson et al, 2011).…”

Applications of ESEM on Materials Science: Recent Updates and a Look Forward

“…In this case, the information of shape/arrangement of microstructures and element distributions on fossils can be extracted by ESEM so that to provide paleogeographic environmental data of stratigraphic formation for determining geological age and stratigraphic correlation. Many studies about fossils based on ESEM have hence made significant contributions to cultural heritage conservation . For example, McPherron et al observed the fossilized bones under ESEM and found unambiguous stone‐tool cut marks for flesh removal and percussion marks for marrow access.…”