New Maikhanellid Shells and Siphogonuchitid Spicule Bundles from the Cambrian Fortunian Stage of South China  

作　　者：LIU Yunhuan ZHANG Yanan SHAO Tiequan TANG Hanhua JIANG Kaituo WANG Qi CHEN Cheng DONG Junyan LIANG Yongchun DAI Jun XUE Jiaqi 

机构地区：[1]School of Earth Sceince andResouces, Chang'an University, Xi'an 710054, China [2]Key Laboratory for the study of FocusedMagmatism and Giant Ore Deposits, MLR, Xi 'an 710054, China

出　　处：《Acta Geologica Sinica(English Edition)》2016年第5期1629-1636,共8页地质学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(41572009,41572007, 41472015);College Students' Innovative Entrepreneurial Training Program of Chang'an University(Grant No. 201610710043,201610710044,201610710047, 201610710045),0012-310600161000;The Tenth "Challenge Cup" Competition of Chang'an University (C-P-B-2,C-P-B-6,C-P-B-8)

摘　　要：Maikhanellids are a distinct group of Cambrian Fortunian small shelly fossils by the capshaped profiles and scaly shell ornamentation.According to the individual shell shape and ornamentation feature types of 50 maikhanellids fossils which were collected from Xixiang botia,we confirmed the family Maikhanellidae content of six genera,which are Maikhanella,Ramenta,Purella,Ramentoides,Yunnannopleura and Mediata.Unlike the halkieriid animals whose shells and spicules are articulated on different body parts,maikhanellids were presumably yielded by siphogonuchitid spicules penetrating the intermediate matrix（the ＂spicule shell＂ hypothesis）,and this is the reason that some researchers treated maikhanellids and co-occurring siphogonuchitids as synonyms.The affinities of Maikhanellids and siphogonuchitids remain debatable.Here,we report three dimensionally phosphatized maikhanellid shells and siphogonuchitid spicule bundles from the Cambrian Fortunian small shell faunas of South China.They differ from all the previously reported maikhanellids and siphogonuchitids,and may represent new types.The intact and smooth surface underneath the partially preserved scales of the shells challenges the ＂spicule-shell＂ hypothesis.The present siphogonuchitid spicules differ from the maikhanellid scales in size,morphology,and.arrangement pattern,thus the spicules might not be derived from the shells.Whether the shells and spicule bundles were articulated on different body parts of the same animals remains unknown.Maikhanellids are a distinct group of Cambrian Fortunian small shelly fossils by the capshaped profiles and scaly shell ornamentation.According to the individual shell shape and ornamentation feature types of 50 maikhanellids fossils which were collected from Xixiang botia,we confirmed the family Maikhanellidae content of six genera,which are Maikhanella,Ramenta,Purella,Ramentoides,Yunnannopleura and Mediata.Unlike the halkieriid animals whose shells and spicules are articulated on different body parts,maikhanellids were presumably yielded by siphogonuchitid spicules penetrating the intermediate matrix（the ＂spicule shell＂ hypothesis）,and this is the reason that some researchers treated maikhanellids and co-occurring siphogonuchitids as synonyms.The affinities of Maikhanellids and siphogonuchitids remain debatable.Here,we report three dimensionally phosphatized maikhanellid shells and siphogonuchitid spicule bundles from the Cambrian Fortunian small shell faunas of South China.They differ from all the previously reported maikhanellids and siphogonuchitids,and may represent new types.The intact and smooth surface underneath the partially preserved scales of the shells challenges the ＂spicule-shell＂ hypothesis.The present siphogonuchitid spicules differ from the maikhanellid scales in size,morphology,and.arrangement pattern,thus the spicules might not be derived from the shells.Whether the shells and spicule bundles were articulated on different body parts of the same animals remains unknown.

关 键 词：maikhanellids siphogonuchitids Cambrian Fortunian Stage South China 

分 类 号：P534.41[天文地球—古生物学与地层学] Q915[天文地球—地质学]