SPHENOTHALLUS HALL,1847 FROM THE TSINGHSUTUNG FORMATION(QIANDONGIAN SERIES,CAMBRIAN)IN BALANG VILLAGE OF JIANHE COUNTY,GUIZHOU PROVINCE,CHINA

The Tsinghsutung Formation(Qiandongian Series,Cambrian)of Songshan Section near Balang village,Jianhe County,Guizhou Province is mainly composed of limestone and mudstone,interbeded with mudstone and limestone in the upper part,and medium-bedded dolomite for the uppermost section.The upper part of the Tsinghsutung Formation belonging to the Redlichia(R.)guizhouensis-Redlichia(R.)nobilis Acme Zone is rich in ptychopariids,trilonites,mollusks and other invertebrate fossils including a few soft-body fossils.So far only 1 species,Sphenothallus cf.taijiangensis Zhu et al.,2000 has been found in this zone.A few well-preserved fossil specimens are described here with obvious annulations on the wall tube,indicating the Sphenothallus had conical-tubular skeleton.Sphenothallusfrom the Tsinghsutung Formation not only enriches the assemblage of the Tsinghsutung Formation biota,but also provides new material for the research of Sphenothallus.The preliminary study shows that a evolutionary trend exists for the lengthening individuals,widening longtitudinal thickenings,and diminishing apertual expandings.The Sphenothallus have affinities with polypoid hydrozoans or scyphozoans.