Marine Biology Commons^™

Taphonomy Of Isocrinid Stalks: Influence Of Decay And Autotomy, Tomasz K. Baumiller, Ghislaine Llewellyn, Charles G. Messing, William I. Ausich

Marine & Environmental Sciences Faculty Articles

Stalks of isocrinid crinoids are differentiated into cirri-bearing columnals (nodals) and columnals lacking cirri (internodals). This skeletal differentiation allowed us to test whether stalk fragmentation is random or whether it occurs preferentially at a specific articulation. Our analyses indicate that the patterns of fragmentation in multicolumnal segments of extant isocrinids collected by submersible, by dredging, and in sediment samples, as well as those found as fossils, are nonrandom. The preferred plane of fragmentation corresponds to the synostosis, the articulation between a nodal and the internodal distal to it. In isocrinids this articulation has a characteristic morphology and is the site …