Changes in the trace fossil biota across the Proterozoic-Phanerozoic boundary

Abstract

Trace fossils became relatively diverse in shallow-water clastic seas in the late Proterozoic (Vendian), with a further significant increase in abundance, diversity and complexity in the Tommotian and Atdabanian. Little change followed in the remainder of the Lower Palaeozoic. Traces typical of deeperwater facies evolved in shallow water during the Vendian and early Cambrian, and may have slowly migrated into the deep ocean during the remainder of the

First Ediacaran Fauna Occurrence in Northeastern Brazil (Jaibaras Basin, ?Ediacaran-Cambrian): Preliminary Results and Regional Correlation

“…In addition, the association of these specimens with Planolites montanus eliminates any possibility of their being sedimentary structures. Notably, Crimes (1992) included Arenicolites and Planolites in his review of ichnofossils appearing in the Neoproterozoic and crossing the Neoproterozoic-Cambrian boundary, corroborating the data presented here. These data refute the claim by Gehling et al (2001) that Arenicolites have not been convincingly described in Neoproterozoic strata but are often confused with inorganic structures.…”

Hierarchical random walks in trace fossils and the origin of optimal search behavior

“…Our results confirm that search patterns that are driven by simple behaviors and approximate theoretically optimal Lévy walks may have an ancient origin. The earliest such fossil trails comprise patterns that often cross themselves and indicate relatively crude foraging behaviors (34). More complex traces in the form of surface trails or shallow burrows that meander or spiral and are self-avoiding are first recorded in the Lower Cambrian trace fossil record, ∼540 Ma (34).…”

“…The earliest such fossil trails comprise patterns that often cross themselves and indicate relatively crude foraging behaviors (34). More complex traces in the form of surface trails or shallow burrows that meander or spiral and are self-avoiding are first recorded in the Lower Cambrian trace fossil record, ∼540 Ma (34). Numerical simulations of Darwinian evolution of behavioral programming suggest that in environments with homogenous food supply, competition between individuals should favor trails with maximum coverage and minimal recrossing of existing tracks (35).…”

Remarkable preservation of microbial mats in Neoproterozoic siliciclastic settings: Implications for Ediacaran taphonomic models

“…hexactinellid sponges and radiolarian rhizopods; Bengtson, 2004) is predicted to have reduced oceanic silica concentrations (Perry & Lefticariu, 2003;Maliva et al, 2005). The onset of significant infaunal bioturbation (Seilacher, 1956;Crimes, 1992;Seilacher & Pflüger, 1994;McIlroy & Logan, 1999;Droser et al, 2002a;Jensen, 2003;Droser et al, 2004), increased the average depth of the mixed layer and therefore reduced the concentration of ions in porewaters (e.g. silicate and carbonate) as well as increasing the average depth of processes leading to pyritization and phosphatization of carbonaceous materials (Fig.…”

“…Since that time, considerable strides have been made in our understanding of the changes in both the physical and the chemical nature of the uppermost layers of marine sediments, owing to these coeval explosions of bioturbation and biomineralization (e.g. Crimes, 1992;Seilacher & Pflüger, 1994;Droser et al, 1999;Seilacher, 1999;Bottjer et al, 2000;Droser et al, 2002a;Jensen, 2003;Bengtson, 2004;Dornbos et al, 2004;Droser et al, 2004;Seilacher et al, 2005).…”