我国西南地区早寒武世小壳化石Sinosachites

采自四川峨嵋和云南会泽的磷酸盐化的Sinosachites骨片显示出中央沟和侧沟结构，并区别出三种不同类型的骨片(palmate，cultrate and siculate)。这一发现证实，产于澳大利亚的Thambetolepis(Jell，1981)是Sinosachites的晚出同义名。基于上述结构，该产地一些原定为Sachites和Halkieria的标本亦应归入Sinosachites。在Sinosachites属中确认出两个种，即产于华南的Sinosachites flabelliformis He和产于澳大利亚的Sinosachites delicatus(Jell)。在前一种中，左右型对称骨片的存在证实该动物两侧对称。骨片的基部通常保存为磷质内核，表明它比骨片壁更容易磷酸盐化，在组织学上它与骨片壁不同。骨片的基部可能原为有机质或部分矿化。在Sinosachites中，无帽状和束状骨片可能表明在coeloscleritophorans中halkieriids是一个介于wiwaxids和siphogonuchitids之间的类群。

EARLY CAMBRIAN SMALL SHELLY FOSSIL SINOSACHITES FROM SOUTHWEST CHINA

Phosphatized Sinosachites sclerites from its type locality--Emei,Sichuan and another locality--Huize,Yunnan,reveal the existence of central and lateral canal structures in sclerites. Three kinds (palmate,cultrate and siculate) of sclerites can be distinguished. This finding makes the Australian Thambetolepis (Jell,1981) a junior synonym of Sinosachites (He,1980). Some species formerly named under the genera Sachites and Halkieria are considered here as Sinosachites based on the same canal structures.Two species are distinguished in the genus,i.e.the Chinese Sinosachites flabelliformis He and the Australian Sinosachites delicatus (Jell).Left right sclerite pairs are found which proves a bilaterally symmetrical body of the animal.The kind of the sclerite base preservation,usually as phosphatic steinkern,shows that it is easier to be phosphatized than the mineralized sclerite wall,which suggests that the base is histologically different from the latter.A possible organic or partially mineralised situation is proposed.The fact that no cap-shaped shell and bundled sclerites found together with the isolated sclerites in Sinosachites may indicate that halkieriids is a group between wiwaxids and siphogonuchitids in coeloscleritophorans.