Journal of Paleontology, 92(6), 2018, p. 982–1004 Copyright © 2018, The Paleontological Society 0022-3360/15/0088-0906 doi: 10.1017/jpa.2018.29


Silurian amplexoid rugose coral genera Pilophyllia Ge and Yu, 1974 and Neopilophyllia new genus from South China


Guang-Xu Wang,1 Xin-Yi He,2 Lan Tang,3 and Ian G. Percival4


1State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, China ⟨gxwang@nigpas.ac.cn⟩ 2China University of Geosciences, 29 Xueyuan Road, Beijing 100083, China ⟨hexinyi2007@126.com⟩ 3College of Resources and Metallurgy, Guangxi University, Nanning 530004, China ⟨tlan1990@126.com⟩ 4Geological Survey of New South Wales, 947−953 Londonderry Road, Londonderry, New South Wales 2753, Australia ⟨ian.percival@planning. nsw.gov.au⟩


Abstract.—Pilophyllia Ge and Yu, 1974 represents a major group of distinctive amplexoid corals in the Silurian, whose taxonomic relationships, species composition, and evolutionary trends remain contentious. A critical revision of type material and new specimens of several species (and subspecies) assigned to Pilophyllia, including the type species P. involuta Ge and Yu, 1974, provides solutions to some of these problems. Pilophyllia is revised to include only those forms characterized by a distinct peripheral stereozone and amplexoid major septa with club-shaped rhab- dacanths set in thick lamellar stereomes. Other species, previously referred to Pilophyllia but having generally short septa with wedge-shaped rhabdacanths, are transferred herein to the new genus Neopilophyllia Wang. Both genera, together with other Silurian amplexoid rugosan genera such as Amplexoides, are referred to the new family Amplex- oididae Wang, which is thought to be evolutionarily unrelated to the much younger (Devonian to early Carbonifer- ous) amplexoid rugosan family Amplexidae Chapman, 1893. The first appearance of Neopilophyllia n. gen. in the middle Telychian, much later than that of Pilophyllia in the late Rhuddanian, probably marks a significant stage dur- ing the evolution of Silurian amplexoid corals.


UUID: http://zoobank.org/c22423b0-7af2-4be0-8ac2-7d47addde621 Introduction


Amplexoid corals are characterized by development of amplexoid septa throughout their ontogeny, representing a dis- tinctive clade of rugose corals in the Silurian (Hill, 1981; Chen et al., 1997). Pilophyllia Ge and Yu, 1974, currently with more than 20 assigned species of various morphologies, forms a substantial component of the clade (Wang et al., 1986; Tang et al., 2007). However, there is considerable uncertainty con- cerning the species composition of the genus, whose taxonomic relationships have been queried by some authors (e.g., He and Tang, 2013; McLean and Copper, 2013) due to insufficient documentation of the type species, P. involuta Ge and Yu, 1974. The phylogeny and evolutionary trends of Pilophyllia are also not well understood with many early species introduced by Ge and Yu (1974), Cao (1975), and Cao and Lin (1982) being poorly characterized. To resolvetheseproblems,werestudied thetypematerialof


various species (and subspecies) of Pilophyllia, including P. involuta and many of the problematic ones mentioned above, as well as several new specimens of these forms, from Aeronian and Telychian rocks of many areas of southwestern China (Fig. 1). The present paper aims to reassess the species composition of Pilo- phyllia, to document the newly introduced genus Neopilophyllia n.


gen. associated with a revised definition of Pilophyllia, and thus to explore the morphological trends of this species group, with an emphasis on evolutionarily significant characteristics of septal microstructure and minor septal development.


Materials and methods


All specimens examined and cited in this paper occurred in various horizons of early Silurian age in South China (Fig. 2). Of vital importance are type specimens of several species belonging to Pilophyllia that have been documented by Ge and Yu (1974), Cao (1975), and Cao and Lin (1982), because all of these species are insufficiently known particularly in terms of diagnostically important features of septal microstructure. In view of recent great progress on the stratigraphic correlation of Silurian rocks in South China (Rong et al., 2012), the age con- straint on the studied material provided in the original publica- tions has been revised according to the most recent stratigraphic framework (Fig. 2). In addition, several new specimens, particularly those of


the type species of Neopilophyllia n. gen., are studied in detail to establish it as a new genus. These materials were collected from the Ningqiang Formation (middle Telychian) of the Ningqiang area, southern Shanxi Province, by staff members of the former


982


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190