Article: Scroll coprolites from the Silurian of Ireland and the feeding of early vertebrates

The morphology of scroll coprolites from the post-Llandovery Silurian of Louisburgh, Co. Mayo, Ireland is described. The coprolites occur within relatively fine-grained laminites along with the anaspid agnathan Birkenia elegans the dermal scales of Loganellia, and the enigmatic 'Glauconome'. Such a faunal association also exists in the Midland Valley of Scotland. The significance of detritus as a nutrient source and the evolution of particulate feeding among the early vertebrates is examined. By association, Birkenia and/or Loganellia appear to be the most likely producers. The coprolites in the present study are the oldest known vertebrate spiral coprolites, and the first scroll coprolites to be associated with what are at present considered to be agnathans. The coprolites represent evidence for the early development of valvular intestines, of which the scroll valvular intestine now appears to be the more primitive. These coprolites also provide some of the first definite indications that particulate feeding was of significance among early vertebrates.