Coprolites and fecal pellets in a late carboniferous coal swamp: morphologic and paleoecologic analysis

Abstract

Permineralized peats provide an excellent opportunity to study the ecology of the coal swamps of the Upper Carboniferous. In this study, I examine the coprolites and fecal pellet accumulations in pertnineralized peats from the Williamson No. 3 mine of Lucas Co. Iowa. Six types of coprohtes, which are distinguished based on color, texture and shape, occur in the Williamson No. 3 peat. Cordaites, a gymnosperm group allied to the conifers, and medullosan seed-fems, a gymnospenn group allied to the cycads, dominated this coal swamp. The size frequency distribution of coprolites and the frequency of pelletization (defined as the occurrence of fecal pellets within plant tissue or matrix) within these peats suggest that Medullosa communities supported larger detritivores than the Cordaites communities. In addition, rates of pelletization of Medullosa and Cordaites organs and matrix indicate that Medullosa debris represented a more palatable resource to the detritivore community than Cordaites debris. With more pelletization and larger detritivores, it is likely that Medullosa communities maintained higher rates of nutrient cycling and higher levels of productivity than the Cordaites communities. The results of this study suggest that coprolite and fecal pellet assemblages can be used to map rates of nutrient cycling and primary productivity.