The Wangchengpo Frasnian section of Dushan County contains two atrypid brachiopod assemblages. The lower is characterized by the Atryparia (Costatrypa) dushanensis fauna that appears at the base of the Hejiazhai Member approximately in the falsiovalis to transitans conodont zones; the upper is characterized by the Radiatrypa yangi fauna, which appears in the Lujiazhai Member approximately correspondent with the hassi to Upper rhenana conodont zones. Atrypid brachiopods, together with other brachiopods from the Dushan section show that the Hejiazhai Member is of Frasnian age. Preliminary analyses of Frasnian atrypid brachiopods from sections of South China indicate that there are nine genera and subgenera including Atryparia (Costatrypa), Kyrtatrypa, Spinatrypa, Isospinatrypa, Spinatrypina, Iowatrypa, Desquamatia (Desquamatia), Desquamatia (Seratrypa), and Radiatrypa. Atrypid species diversity did not change much through the Frasnian. On a regional scale in South China, most atrypid species went extinct prior to the Frasnian/Famennian boundary. At any specific locality or section, these atrypids became extinct about 20–40 m below the Frasnian/Famennian (F/F) boundary, within the linguiformis conodont Zone, marking this as the major extinction level. Three new atrypid species are described: Atryparia (Costatrypa) dushanensis, Iowatrypa pseudobodini, and Radiatrypa yangi.
A group of radiolarian fossils with a complete morphological gradient of increasing polarization are reported from upper Devonian successions in southwestern Tianshan,China.Specifically,the important transitional mophotypes,Pylentonema transitorum sp.nov.,Archocyrtium medium sp.nov.and Quadrapesus transitivus sp.nov.,were found.Based on the fact that the new transitional radiolarian fossils resemble more closely to pylentonemids(cyrtoid nassellarians)than to entactinids(spumellarians)in morphology,they are assigned to pylentonemids.Pylentonemids share characters of both the Nassellaria(e.g.,horned cephalis,basal opening with pylome)and Spumellaria(e.g.,system of trabecular spicules),and they are thus of evolutionary significance.The evolutionary trend from spumellarians to nassellarians is characterized by(1)internal spicule:from simple trabecular spicules to complicate components(A;lr,ll;D;V;Lr,Li;MB);(2)polarization of the radiolarian tests due to rearrangment of spine,from radial to an axial symmetry;(3)the gradual formation of a basal opening(aperture,pylome,or podome);and the transition from a pseudopylome,a primative pylome with a narrow margin on the outer shell,to a true pylome rimmed with a narrow,elevated impermite wall.
