Abstract During the Carboniferous, crinoids were commonly so abundant that their skeletal ossicles formed limestones termed encrinites. Major evolutionary changes occurred within the Camerata and Articuliformes, as the former were displaced by the latter as the dominant clade. Both the Mississippian and the Pennsylvanian subperiods started with high evolutionary rates and ended with low evolutionary rates associated with glaciation. Although not typically used for biostratigraphy, crown-based crinoid genera can be used as biostratigraphic indicators for Carboniferous stages. Paleozoic crinoid biodiversity reached its maximum during the Carboniferous, from which there are numerous well-documented localities with high biodiversity. Faunas from the palaeobiogeographical regions of Laurussia, Palaeo-Tethys and Gondwana are reviewed. For Mississippian crinoids, 37 genera are designated as biostratigraphically useful; and, for the Pennsylvanian, 44 genera are identified. Recognition of the utility of these genera for biostratigraphy is important for dating crinoid deposits, which may be devoid of other biostratigraphically useful fossils, and add to our overall ability to delineate the temporal resolution of life on Earth.

Abstract The Late Devonian, Famennian, Hongguleleng Formation of northwestern China has yielded one of the most diverse echinoderm faunas known from China. New collections and re-evaluation of earlier collections results in recognition of new taxa, increases the known diversity, provides new morphological information on some of the previously reported taxa, and provides new information on the affinity of the Late Devonian echinoderms of the Hongguleleng Formation. New crinoid taxa introduced are Gnarycrinus lanei n. gen., n. sp., Anamesocrinus tieni n. sp., Histocrinus ? chenae n. sp., Eumhacrinus tribrachiatus n. gen., n. sp., Sostronocrinus aberratus n. sp. and Labrocrinus granulatus n. gen., n. sp. One new species of blastoid, Hadroblastus liaoi , n. sp. is described. Previous reports listed 46 echinoderms from the Hongguleleng Formation, including 13 blastoids and 33 crinoids. An additional 11 crinoid species bring the total crinoids to 44 species assigned to 32 genera. Similarly, the one additional species of blastoid brings the totals to 14 species assigned to 12 genera. The new echinoderms described herein include the first report of a dimerocrinitid, amphoracrinid, allagacrinid, glossocrinid, histocrinid, cercidiocrinid, dactylocrinid and neoschismatid from the Devonian of northwestern China. Additional morphologic information is provided for three of the previously described taxa and a revision of species assigned to Grabauicrinus is proposed. The crinoids and blastoids suggest closer affinity with Mississippian faunas than with Devonian faunas, and with North American faunas than European faunas. Collectively the blastoid and crinoid faunas from the Hongguleleng indicate that rediversification happened rapidly after extinction in contrast to current suggestions of a long interval of lowered origination following these extinction events.