Stratigraphical and geographical distribution of Mississippian (Lower Carboniferous) Crinoidea from Scotland

Abstract

ABSTRACTA total of 47 genera, in 80 species, of Mississippian, or Lower Carboniferous, crinoids are evaluated from 61 localities in Scotland based on a modern update of the literature, study of museum collections, and new field work. Among the 80 species, 76 are considered valid, with eight requiring new combinations of genus and species names. In addition, one species is considered anomen dubium, and three can only be assigned at the generic level. Asbian faunas have a moderate generic richness of 13. Brigantian faunas have the highest generic richness at 40. Arnsbergian faunas have the lowest generic richness at three. There are no Mississippian crinoid faunas in Scotland older than Asbian. The dominant Brigantian crinoid faunas occur in limestones and shales in the shallow shelf marine intervals of Yoredale-style cyclothems. The Asbian faunas occur in shallower, nearshore mudstones and limestones of Yoredale-style cyclothems. The late Viséan (Brigantian) fauna is more similar in overall taxonomic composition to the global record for the Serpukhovian rather than the Viséan. This reflects the establishment of the Late Palaeozoic Crinoid Macroevolutionary Fauna, dominated by advanced cladid crinoids, by the end of the Viséan in Scotland.