POLYMERID TRILOBITES FROM THE CAMBRIAN OF NORTHWESTERN HUNAN, CHINA Volume 1 Corynexochida, Lichida, and Asaphida PENG Shanchi Loren E. BABCOCK LIN Huanling Science Press Beijing · i· Responsible Editresses: HU Xiaochun and LIN Caihua POLYMERID TRILOBITES FROM THE CAMBRIAN OF NORTHWESTERN HUNAN, CHINA Volume 1 Corynexochida, Lichida, and Asaphida PENG Shanchi, Loren E. BABCOCK, and LIN Huanling Copyright © 2004 by Science Press Published by Science Press http://www. sciencep. com 16 Donghuangchenggen North Street Beijing 100717 P. R. China Printed in Beijing, 2004 Reprinted in Beijing, 2006 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the copyright owner. ISBN 7-03-014905-X/Q· 1538 · ii· LIST OF AUTHORS PENG Shanchi Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences 39 East Beijing Road Nanjing 210008, China Loren E. BABCOCK Department of Geological Sciences The Ohio State University 275 Mendenhall Laboratory 125 South Oval Mall Columbus, Ohio 43210, USA LIN Huanling Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences 39 East Beijing Road Nanjing 210008, China · iii· This research was funded by National Natural Science Foundation of China (49070077, 40072003, 40023002, 40332018) Chinese Academy of Sciences (KZCX2-SW-129) Ministry of Technology and Science of China (2001 DEB20056, G2000077700) National Geographic Society (No. 5819-96; 7151-01) State Key Laboratory of Paleobiology and Stratigraphy (No. 933114) State Education Commission of China The Ohio State University US National Science Foundation (EAR 9405990, 9526709, 0073089, 0106883, EAR OPP-0346829) · iv· FOREWORD China is richly endowed with Cambrian strata yielding some of the best-preserved fossils known anywhere in the world. The trilobites are most important element in the fauna, and of scientific relevance for several reasons. First, they are of regional importance in the precise correlation of strata, and are of primary use in characterising mappable formations. Second, some of the species are widespread internationally, and these permit the placing of Chinese stratigraphical schemes within the global chronostratigraphy. Thirdly, the variety, relationships and endemicity of the faunas contributes to the broad questions of how evolution proceeded in the Cambrian, and is relevant to debates about whether special conditions applied at the early stage of the Phanerozoic radiation. The polymerid trilobite faunas of northwestern Hunan are remarkable for their diversity and excellence of preservation. Many of them belong to genera confined to China or to its palaeogeographic neighbours. However, some of these important taxa have remained imperfectly known or undescribed. This monograph makes good this omission. Thus in several cases pygidia or free cheeks are assigned where they had not been known previously, thus providing a much fuller picture of morphology in assessing relationships. This is particularly welcome where the species concerned is the type of its genus. In addition a number of new genera are added to the fauna. The paper also documents the endemic radiation of the specialised and interesting Dameselloidea, a family showing some of the most specialised pygidia in the Trilobita. The systematics of these trilobites is fully discussed, and the whole work is illustrated by photographs of the highest quality. This work should remain the standard account for the foreseeable future. The detailed work on the trilobites is placed in the wider context of biostratigraphy and correlation, which should be of interest to all those concerned with Cambrian geology. A refinement of the biostratigraphic zones based on the ranges of trilobite species will have implications for those currently seeking to increase the precision in international correlation of subdivisions within the Cambrian. Careful new work, of which this paper is an excellent example, is a more valuable contribution than almost anything else in this endeavour. Professor Richard A. Fortey F R S Department of Palaeontology The Natural History Museum and Department of Zoology Oxford University · i· CONTENTS FOREWORD..................................................................................................................................... i INTRODUCTION............................................................................................................................ 1 ACKNOWLEDGMENTS.......................................................................................................... 2 REPOSITORIES ........................................................................................................................ 2 PREVIOUS WORK......................................................................................................................... 3 GEOLOGIC SETTING................................................................................................................... 4 PALEOGEOGRAPHY .............................................................................................................. 4 STRATIGRAPHY ..................................................................................................................... 4 MEASURED SECTIONS........................................................................................................ 10 CORRELATION............................................................................................................................ 40 NORTH CHINA AND NORTHEAST CHINA PLATFORMS .............................................. 40 TARIM AND NORTHWEST CHINA .................................................................................... 40 WESTERN ZHEJIANG........................................................................................................... 42 AUSTRALIA ........................................................................................................................... 42 BALTICA................................................................................................................................. 42 KAZAKHSTAN....................................................................................................................... 43 LAURENTIA ........................................................................................................................... 43 SIBERIA .................................................................................................................................. 43 SYSTEMATIC PALEONTOLOGY ............................................................................................ 44 Class TRILOBITA Walch, 1771.................................................................................................. 44 Order CORYNEXOCHIDA Kobayashi, 1935 ............................................................................... 44 Suborder CORYNEXOCHINA Kobayashi, 1935 .......................................................................... 44 Family CORYNEXOCHIDAE Angelin, 1854................................................................................ 44 Genus CORYNEXOCHUS Angelin, 1854 .................................................................................... 44 Corynexochus xiangxiensis sp. nov.................................................................................. 45 Genus CORYNEXOCHINA Lermontova, 1940 ............................................................................ 46 Corynexochina sinensis sp. nov. ...................................................................................... 47 Genus CHATIANIA Yang in Zhou et al., 1977........................................................................... 48 Chatiania chatianensis Yang in Zhou et al., 1977........................................................... 49 Chatiania expansa (Yuan and Yin, 1998)........................................................................ 52 Chatiania sp. cf. C. chatianensis Yang in Zhou et al., 1977............................................ 53 Chatiania convexa sp. nov. .............................................................................................. 53 Family DOLICHOMETOPIDAE Walcott, 1916............................................................................. 54 Genus AMPHOTON Lorenz, 1906 .............................................................................................. 54 Amphoton deois (Walcott, 1905)...................................................................................... 56 Amphoton alceste (Walcott, 1905) ................................................................................... 57 Amphoton sp. cf. A. typicum (Kobayashi, 1942a) ............................................................ 59 Genus FUCHOUIA Resser and Endo in Kobayashi, 1935 .......................................................... 60 Fuchouia chiai Lu, 1957 ................................................................................................. 62 Fuchouia kuruktagensis Zhang, 1981 .............................................................................. 64 · iii· Fuchouia oratolimba Yang in Zhou et al., 1977.............................................................. 65 Fuchouia bulba sp. nov.................................................................................................... 67 Fuchouia sixinensis sp. nov.............................................................................................