Journal of Paleontology, 92(4), 2018, p. 525–545 Copyright © 2018, The Paleontological Society 0022-3360/18/0088-0906 doi: 10.1017/jpa.2017.133


Two new species of Nilssoniopteris (Bennettitales) from the Middle Jurassic of Sandaoling, Turpan-Hami Basin, Xinjiang, NW China


Yi Zhao,1 Shenghui Deng,2 Ping Shang,3 Qin Leng,4 Yuanzheng Lu,2 Guobin Fu,5 and Xueying Ma2


1School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China ⟨106000890@qq.com⟩ 2Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China ⟨dsh63@petrochina.com.cn⟩,


⟨luyz@petrochina.com.cn⟩, ⟨752032397@qq.com⟩ 3Yantai Gold College, Yantai 264000, China ⟨shangp@tust.edu.cn⟩ 4College of Arts and Sciences, Bryant University, Smithfield, RI 02917, United States ⟨qleng@bryant.edu⟩ 5Research Institute of Petroleum Exploration and Development, PetroChina Tuha Oilfield Company, Hami 839009, China ⟨fgbyjy@petrochina.com.cn⟩


Abstract.—Two new species of Nilssoniopteris of the order Bennettitales, Nilssoniopteris hamiensis Zhao and Deng, new species and Nilssoniopteris crassiaxis Zhao and Deng, new species, are established from the Xishanyao Formation (Middle Jurassic) of Sandaoling Coal Mine in Hami, Xinjiang, China, based on leaf macromorphology and cuticular features. Nilssoniopteris hamiensis n. sp. is characterized by its varied leaf shapes and trichome bases of 1–4 cells on the abaxial epidermis. Nilssoniopteris crassiaxis n. sp. is characterized by its broad midrib (especially near the leaf base) and trichome bases of 1–3 cells on the abaxial epidermis. Both species possess unique venation patterns that are not only simple and free, but also forked and merged to form closed loops. These anastomosing veins are even more complicated in N. crassiaxis n. sp. in that the veins can fork once, twice, or even three times, the forked veins can later merge with each other or with an adjacent vein to form a closed loop, which may later further disjoin. The generic diagnosis of Nilssoniopteris is thus accordingly emended, particularly in the venation pattern. In addition, the stratigraphic and geographical distributions of all 45 Jurassic Nilssoniopteris species worldwide have been summarized and analyzed to better understand their brief evolutionary history, indicating that Nilssoniopteris might be able to grow not only in subtropical regions as the living cycads are, but also in warm climatic regions.


Introduction


The Turpan-Hami Basin is located in the eastern part of the Xinjiang Uygur Autonomous Region, NW China, which is divided into the western Turpan Depression and the eastern Hami Depression. The Jurassic flora in the Xishanyao Forma- tion of the Hami Depression is one of the representatives of


Middle Jurassic floras of China. The earliest report about this flora came in 1981 in regional geological survey reports as a species list (WGRSCXUAR, 1981), followed by a brief description of ex situ and in situ cuticles (S.-J.Wang et al., 1994; Zhang et al., 1997). After that, for nearly two decades, brief systematic studiess gradually culminated in a list of nearly 90 species (Shang et al., 1999; Deng et al., 2010). More detailed descriptions appeared only recently, including a new conifer species with cones (Wang et al., 2015), a new species of Ginkgo bearing male cones (Wang et al., 2017), and a new thalloid liverwort (Li et al., 2016). In this paper, we provide a detailed report on both macromorphological and cuticular features of more than 40 Nilssoniopteris specimens among thousands of fossils collected by SHD and his colleagues during the past two decades. We also reviewall known Jurassic species


of Nilssoniopteris and establish two new species from the flora: N. hamiensis Zhao and Deng, n. sp. and N. crassiaxis Zhao and Deng, n. sp. Prior to our study, no cycadophytes from this


flora had been studied by means of macromorphology and epidermal anatomy, and among the reported Jurassic Nilssoniopteris species previously reported from North China (Zhang et al., 1976; Wang, 1984; Li et al., 1988; Sun and Shen, 1988; Sun and Yang, 1988), few had been observed by SEM. Thus, this study represents the first comprehensive macro- and micro-morphological and anatomical observation of Nilssoniopteris from the Xishanyao Formation. The genus Nilssoniopteris Nathorst, 1909 is one of the com-


mon genera among the Mesozoic Bennettitalean leaf fossils, with about 84 species reported,most from the Northern Hemisphere with a few scattered records in the Southern Hemisphere (e.g. Harris, 1932b; Carpentier, 1938; Samylina, 1963; Krassilov, l967; Ash, 1978; Kiritchkova, 1985; Daniel, 1989; Zhou, 1989; Watson and Sincock, 1992; Deng, 1995; Kvaček, 1995; Boyd, 2000; Pott et al., 2007; Yamada et al., 2009). This genus first occurred in Upper Triassic beds (Pott et al., 2007) and extended into the Late Cretaceous (Daniel, 1989;Kvaček, 1995), with Middle Jurassic and Early Cretaceous times representing two peaks in its evolutionary history. Before the present study, 43 species of Nilssoniopteris had been reported from the Jurassic (Supplementary Data Set and references therein), and the establishment of the two new species in this study from the Middle Jurassic of Hami, Xinjiang, China further extends the paleogeographic distribution of Jurassic Nilssoniopteris in the Northern Hemisphere.


525

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  |  Page 191  |  Page 192  |  Page 193  |  Page 194  |  Page 195  |  Page 196  |  Page 197  |  Page 198  |  Page 199  |  Page 200  |  Page 201  |  Page 202  |  Page 203  |  Page 204  |  Page 205  |  Page 206  |  Page 207  |  Page 208  |  Page 209  |  Page 210  |  Page 211  |  Page 212  |  Page 213  |  Page 214  |  Page 215  |  Page 216  |  Page 217  |  Page 218  |  Page 219  |  Page 220  |  Page 221  |  Page 222  |  Page 223  |  Page 224  |  Page 225  |  Page 226  |  Page 227  |  Page 228  |  Page 229  |  Page 230  |  Page 231  |  Page 232