ASSESSING EVOLUTIONARY PALEOECOLOGICAL PATTERNS IN A LONG-LIVED PALEOZOIC CLADE

Eublastoids, often referred to as blastoids, were a common component of shallow water crinoid communities throughout the Paleozoic. Unlike many early Paleozoic blastozoan echinoderm clades, eublastoids are globally distributed, found in a variety of environments, and are temporally expansive with an approximate 200-million-year range. These factors make Eublastoidea an excellent model clade to begin to examine macroevolutionary patterns in the Paleozoic. The clade appears in low abundance and diversity during the Silurian with continual increases in range, diversity, and abundance reaching a peak in the Mississippian. This long temporal range captures the dynamic changes in climate from very warm in the Devonian through the glaciation events of the Carboniferous. Species have been described from a range of deposits indicating varied potential environmental conditions including: low energy microbial mud mounds in the Devonian to high energy carbonate platforms of the Mississippian. In this study, I utilize a recently constructed phylogenetic hypothesis as the framework to begin assessing environmental parameters within eublastoid subclades. Lithologic information gained from literature provides a baseline for mapping these changes onto the evolutionary history of the clade and allows for the estimation of ancestral conditions. Analyses were conducted in R and used the packages phytools, ape, paleotree, and paleobioDB. This is first examined in an evolutionary context and then scaled to time to determine differences in specific geologic time periods and changing environments.