Wide-Gauge Sauropod Trackways from the Early Jurassic of Sichuan, China: Oldest Sauropod Trackways from Asia with Special Emphasis on a Specimen Showing a Narrow Turn
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Swiss J Geosci (2016) 109:415–428 DOI 10.1007/s00015-016-0229-0 Wide-gauge sauropod trackways from the Early Jurassic of Sichuan, China: oldest sauropod trackways from Asia with special emphasis on a specimen showing a narrow turn 1 2 3 4 4 Lida Xing • Martin G. Lockley • Daniel Marty • Jianjun He • Xufeng Hu • 4 5 6 6 7 Hui Dai • Masaki Matsukawa • Guangzhao Peng • Yong Ye • Hendrik Klein • 1 6 8 Jianping Zhang • Baoqiao Hao • W. Scott Persons IV Received: 3 February 2016 / Accepted: 31 August 2016 / Published online: 30 September 2016 Ó Swiss Geological Society 2016 Abstract An Early Jurassic sauropod dinosaur tracksite in simultaneously exhibit high heteropody typical for the Lower Jurassic Zhenzhuchong Formation at the Parabrontopodus-type trackways. The relative length of Changhebian site in Dazu County, Sichuan, is known to pes digits I, II and III is difficult to determine, but is sug- have yielded the trackway of a turning sauropod. A re- gestive of a primitive condition where digit I is less well study of the site shows that all in all there are more than developed than in Brontopodus. Thus far, they are the 100 tracks organized in at least three sauropod trackways. stratigraphically oldest sauropod trackways known from The narrow turn in one of the trackways is confirmed and Asia being Hettangian in age. Previously, the trackway analyzed in greater detail. All of the trackways show a with the narrow turn was reported as the first turning wide gauge similar to Brontopodus-type trackways, but sauropod trackway from Asia, but recently several other turning trackways have been reported suggesting that this behaviour is more commonly found than previously Editorial handling: J.-P. Billon-Bruyat and A. G. Milnes. assumed and is now documented from the Early Jurassic to Late Cretaceous. Most of these examples show tight turns Electronic supplementary material The online version of this of between *90° and as much as 180° suggesting that article (doi:10.1007/s00015-016-0229-0) contains supplementary material, which is available to authorized users. despite their large size sauropods could quite easily and abruptly change their direction of movement. & Lida Xing [email protected] Keywords Sauropod tracks Á Turning trackway Á 1 School of the Earth Sciences and Resources, China China Á Dinosaur locomotion Á Zhenzhuchong University of Geosciences, Beijing 100083, China Formation Á Early Jurassic 2 Dinosaur Tracks Museum, University of Colorado Denver, PO Box 173364, Denver, CO 80217, USA Abbreviations 3 Naturhistorisches Museum Basel, Augustinergasse 2, CHB Changhebian track locality, Chongqing, China 4001 Basel, Switzerland CUGB China University of Geosciences, Beijing 4 L/R Left/right No. 208 Hydrogeological and Engineering Geological Team, Chongqing Bureau of Geological and Mineral Resource P Pes Exploration and Development, Chongqing 400700, China M Manus 5 Department of Environmental Sciences, Tokyo Gakugei S Sauropod University, Koganei, Tokyo 184-8501, Japan P0ML Maximum length of pes 0 6 Zigong Dinosaur Museum, Zigong, Sichuan, China M ML Maximum length of manus WAM Width of the manus angulation pattern 7 Saurierwelt Pala¨ontologisches Museum, Alte Richt 7, 92318 Neumarkt, Germany WAP Width of the pes angulation pattern 8 Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB T6G 2E9, Canada 416 L. Xing et al. 1 Introduction or discussion of the tracksite and all the three visible trackway segments. The main author of this paper inves- The locomotion of sauropod dinosaurs is a challenging tigated the locality again in 2011 and 2015, and the purpose question that can only be answered by integrating both data of the present paper is to present a detailed update, from skeletal remains and trackways. Preserved narrow- description, and interpretation of this important Early and wide-gauge sauropod trackways are essential for Jurassic tracksite. Furthermore, the study gives rare understanding the different gait of these tetrapods that, insights into trackway pattern and gait variability of early solely from skeletons, would remain widely obscure. This is sauropods when changing walking direction and perform- also true for exceptional behaviour, for example when ing a narrow turn. making sharp turns during walking. In Asia, most sauropod tracks are known from the Early Cretaceous, such as the large assemblages of tracks described from Korea (e.g., 2 Geographical and geological setting Lockley et al. 2006; Kim and Lockley 2012) and China (e.g., Lockley et al. 2002; 2014; Xing et al. 2014a), but also The Sichuan Basin contains Early, Middle, and Late smaller assemblages as those from Thailand (Le Loeuff Jurassic vertebrate fossils within a more than 3000 m thick et al. 2002). By comparison the record of Jurassic sauropods depositional sequence (Lucas 2001). Peng et al. (2005) tracks, especially Early Jurassic sauropod tracks, is scarce. described the dinosaur fauna from Zigong area and estab- In China, Early Cretaceous trackways of medium-sized lished a biostratigraphic correlation scheme based on ver- (50 B P’ML\75 cm) and large sauropods (P’ML [75 cm) tebrate fossils. In this scheme, two formations nearly all have a medium to wide gauge pattern and have (Zhenzhuchong and Ziliujing) are identified as Early been referred to Brontopodus-type trackways (Xing et al. Jurassic, two (Xintiangou and Xiashaximiao) as Middle 2014a), while trackways of small sauropods have a narrow Jurassic, and three (Shangshaximiao, Suining, and Pen- to medium gauge and are generally referred to Parabron- glaizhen) as Late Jurassic. topodus-type trackways (Xing et al. 2015a). China’s so far Dazu County is located in the southeast of Sichuan scarce Early Jurassic sauropod track record is comprised Basin. The Changhebian tracksite is located 5 km northeast primarily of Parabrontopodus-type trackways from the of Youting Town. The strata at the site mainly consist of Lower Jurassic Ma’anshan Member of the Ziliujing For- (from bottom to top): abundant fluviatile sandstones from mation of Zigong City, Sichuan (Xing et al. 2014b); Liu- the Upper Triassic Xujiahe Formation which includes six jianpus shunan and cf. Brontopodus-type trackwayss from members, with coal seams in the third and fifth members in the Lower Jurassic Daanzhai Member of Ziliujing Forma- the Youting area. Medium-thick layered siltstones, and tion of Sichuan Province (Xing et al. 2015b); and sauropod fine-grained feldspar quartzitic sandstones with interbed- trackways from the Changhebian tracksite, Chongqing (this ded sandy mudstone form the Lower Jurassic Zhenzhu- paper). Additionally, a poorly-preserved Late Triassic chong Formation (Hettangian) (Fig. 2). This sequence is Eosauropus trackway is known from the uppermost part of capped by Holocene clays. Xujiahe Formation of Longguan, Zigong City, Sichuan The Zhenzhuchong Formation is a 17–68 m thick (Xing et al. 2014c). sequence of shallow lacustrine deposits (Peng et al. 2005), In 1985, Yang Xinglong and Yang Daihuan from the and the tracks are located in the layered siltstones. Abun- Chongqing Nature Museum found nearly a hundred tracks dant plant fossils have been found in the Zhenzhuchong of quadrupedal dinosaurs on top of a siltstone layer of the Formation in the northeastern part of the Sichuan Basin, Lower Jurassic Zhenzhuchong Formation in Changhebian with flora assemblages characterized by ferns, cycads and Village (GPS: 29°2704.1200N, 105°46059.9200E: see Fig. 1), conifers. This floral assemblage significantly differs from Youting Town, Dazu County, Chongqing Municipality. the underlying Upper Triassic Xujiahe Formation (which Yang and Yang (1987) briefly reported this discovery when consists of lycopods, bryophytes and articulatae) and shows describing dinosaur tracks from the Sichuan Basin and features characteristic of the Early Jurassic (Liu et al. 2009). suggested that prosauropods or stegosaurs were the most Qiyangia lilingensis (bivalve) and Palaeolimnadia likely trackmakers. Following a brief study of the site in baitianbaensis (conchostracans) also suggest that the 2001 by Sino-Japanese-American expeditions, Lockley and Zhenzhuchong Formation is Early Jurassic in age (Chen Matsukawa (2009) published a partial map showing an area et al., 2006). Chen et al. (2006) proposed that the Zhen- where a wide-gauge trackway exhibits a sharp left turn and zhuchong Formation of the Sichuan Basin and the Lower they identified this trackway as of sauropod origin, stating Lufeng Formation from Yunnan Province further south, are that this appears to be the oldest sauropod trackway known comparable to each other, while Barrett et al. (2007) sug- from Asia. However, they did not provide a full description gested that the latter is ?Hettangian–?Sinemurian in age. Sauropod tracks from the Jurassic of China: a turning trackway 417 Fig. 1 Geographical setting of the study area and the Changhebian sauropod tracksite in Dazu County, Sichuan Province, China The Zhenzhuchong vertebrate fauna includes the typical material). Using the ratios of width of the pes angulation Lufengosaurus (prosauropod) fauna (Peng et al. 2005; Xing pattern/maximum length of pes (WAP/P’ML) and width et al. 2014b). Dong et al. (1983) have described several of the manus angulation pattern/maximum length of fragmentary Lufengosaurus remains from the southwest manus (WAM/M’ML), gauge (trackway width) was portion and southern margin of Sichuan Basin. calculated for both pes and manus tracks (see Marty 2008; Marty et al. 2010a, b); Table 1). Marty (2008)and Marty et al. (2010a, b) have suggested that 1.0 can be 3 Materials and methods used as an arbitrary threshold to distinguish narrow- gauge from medium-gauge trackways, while 1.2 can be 3.1 Generalities used to divide medium-gauge and wide-gauge trackways, and a value above than 2.0 represents a very wide gauge. The beds of the Changhebian tracksite are inclined at AsnotedbyXingetal.(2016), these categories are approximately 45°, which required specialized moun- somewhat arbitrary divisions between the polar extremes taineering equipment to traverse and study the site in of narrow- and wide-gauge trackways as originally detail (Fig.