A New Type Eocrinoids of Echinoderms from the Balang Formation in  Cambrian at Xiasi Town, Majiang County, Guizhou Province,China

Like Kaili Biota, Balang Fauna in Cambrian also contains abundant eocrinoids fossils including two genera and spe- cies, which are(Julzhoueocrlnus yui Zhao, Parsley et Peng, 2007 and Protogioioeocrlnus yln1(gen. et sp. nov.). New genus and species described occur in the upper part of Balang Formation at Shuli Vi11age, Xiasi Town, Majiang County, Guizhou Province, which is1ocated in the southern part of the Balang Formation distribution area. Protogiof7oeocrlnus ylm (gen. et sp. nov.) is a primitive genus and species of (_;iof7oeocllnus gioioius Zhao, Parsley et Peng, 2008 from the Kaili Formation. Both have deve1oped osculum, nearly spherica1 or spheroida1 theca, 1ong brachioles, but new genus and species differ from thelatter in having1ong inverted conica1 column stalk, nearly spherica1 or e11ipsoida1 theca, 1ong ova1 sutura1 pore andless bronchioles. The discoveryand studyof Protogiof)oeocrinus ylm (gen. et sp. nov.) reviews primitive genus and species of Gio,l)oeocllnus gio6oius and provides evidences for evolutiona1 trend between the two in genera and species such as stalk shortening, 1ong in- verted conica1 column changing to short inverted conica1 column, theca changing g1oba1 in shape, sutura1 pore changing from 1ong ova1 form to round form, more brachioles in number. In addition, the bio1ogica1 diversity of eocrinoids from Balang For- mation is enriched and bio1ogica1 partition of eocrinoids from Balang Formation is enhanced. The G·lizhoueocrlnus yui only oc- cur in the northern part of the distribution area of Balang Formation and ProtogiofJoeocllnus yim (gen. et sp. nov.) only occur in the southern part of the distribution area of Balang Formation.