2007. The Verdun Syndrome: Simultaneous origin of protective armor and infaunal shelters at the Precambrian-Cambrian transition.
In: P. Vickers-Rich & P. Komarower (eds) The Rise and Fall of the Ediacaran
Biota. Geological Society, London, Special Publications 286, 405-414.
of the structurally identifiable latest Ediacaran and earliest Cambrian
infaunal trace fossils represent shelters of animals feeding above the
sediment surface. It is the case with the most complete and oldest
radiometrically dated Precambrian-Cambrian transition strata along the
Khorbusuonka River in northern Siberia, in the basal Cambrian succession at
Meishucun in southern China, richest in small shelly fossils, as well as in
the type succession of the Vendian in Podolia, Ukraine. The oldest traces of
feeding within the mud are known from no earlier than the late Tommotian of
Siberia, Mongolia, Sweden, and Poland. This suggests that the invention of
hydraulic mechanisms of sediment penetration was enforced by predation, not by
trophic needs. Various ways to protect the body by secretion of a mineral
skeleton or building tubes by collected mineral grains were developed by other
animals at the same time. Predation may thus appear to be the triggering
mechanism for the "Cambrian explosion." Subsequent increase in the depth
of bioturbation resulted in a profound change of taphonomic conditions,
artificially enhancing the effects of evolution.