GRAIN-SIZE CONTROLS ON THE SILURO-DEVONIAN COLONIZATION OF NON-MARINE SUBSTRATES BY INFAUNAL INVERTEBRATES

ABSTRACT Throughout the history of life on Earth, sedimentary environments have placed controls trajectory evolutionary innovations. To survive and thrive in newly colonized environments, organisms needed to develop novel behaviors: often evidenced rock record as architectural innovation diversification trace fossil morphology. This study focuses ichnological a response challenges presented by different sediment grain sizes during late Silurian Early Devonian colonization continents invertebrate life. The ichnodiversity ichnodisparity from this interval reveal details biological adopted environmental conditions. Characteristics ichnofaunas terrestrial emergent settings are compared across Silurian-Devonian boundary, within both sand mud dominated successions, identify differences associated with substrate compositions. Two trends revealed: 1) Successions mudrock contain lower than sandstone-dominated successions similar age, potentially due burrowing cohesive versus non-cohesive media. Alternatively, could be preference tracemakers for broader conditions that lead or deposition. 2) maximum size fossils given formation is larger sandstone strata strata. Together, these suggest availability substrates was one factor determining constitution early animal communities behavioral styles continents.