bs_bs_banner Biological Journal of the Linnean Society, 2014, 113, 770–789. With 3 figures Tracking Lower Cretaceous Dinosaurs in China: a new database for comparison with ichnofaunal data from Korea, the Americas, Europe, Africa and Australia MARTIN G. LOCKLEY1*, LIDA XING2, JEONG YUL KIM3 and MASAKI MATSUKAWA4 1Dinosaur Trackers Research Group, University of Colorado Denver, CB 172, PO Box 173364, Denver, CO 80217-3364, USA 2School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China 3Department of Earth Science Education, Korea National University of Education, Cheongwon, Chungbuk 363-791, Korea 4Department of Environmental Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan Received 1 February 2014; revised 11 March 2014; accepted for publication 12 March 2014 Following the recent rapid increase in the reports of tetrapod tracksites in the Cretaceous, especially from the Lower Cretaceous, of China and other parts of East Asia, notably South Korea, a review of the ichnofaunal database from these regions is presented as the basis for comparisons with other Lower Cretaceous ichnofaunas that are abundant and reasonably well documented. These areas include parts of North and South America, especially the western USA, and parts of Europe, including the United Kingdom, Northern Germany, Spain, Italy and Croatia. The Chinese database presently includes about 70 Cretaceous sites, the majority of which are Early Cretaceous in age. Although abundant data are available from many regions, much of it has yet to be synthesized in detail or in standard formats. Moreover, ichnotaxonomy may be variable (provincial) between different regions. Thus, while comprehensive lists of sites are available for some regions (China and South America), in other regions such as South Korea and the western USA data have been compiled primarily on a formation by formation basis. The record for Europe is moderately good, but scattered in the primary literature and in need of further synthesis. The record for Australia and Africa is sparse and also in need of synthesis. The most notable regional differences between ichnofaunas appears to be in the relative abundance of distinctive bird and pterosaur track ichnotaxa in China and Korea in comparison with their scarcity or absence in other regions. The distinctive ichnogenus Minisauripus is also known only in China and Korea as are the majority of known dromaeosaurid track occurrences. Ornithopod-dominated and ornithopod-rich ichnofaunas are widespread and particularly abundant in the late Early Cretaceous Barremian to Albian, of some regions. Most well documented Early Cretaceous ichnofaunas are associated with siliciclastic facies and evidently differ from those associated with carbonate facies. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 770–789. ADDITIONAL KEYWORDS: China – Cretaceous – dinosaurs – footprints – tetrapods. INTRODUCTION only brief discussion of African and Australian track records is possible. It is well known that the rate of In this paper we review what is currently known of discovery of dinosaurs, both avian and non-avian, in dinosaur and other tetrapod tracksites in the Early China has been impressive in recent years, due not Cretaceous of China and other footprint-rich regions least to the steady increase in reports of feathered including Korea, the Americas and Europe. Due to dinosaurs from northeastern China. The majority of variability and limitations in available databases, these come from the Yixian Formation, which is essentially devoid of footprints, evidently because the facies is unsuitable for footprint registration *Corresponding author. E-mail: [email protected] (see Matsukawa et al., 2014). However, this does not 770 © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 770–789 DISTRIBUTION OF EARLY CRETACEOUS DINOSAUR TRACKS 771 mean that tracksites are rare in the Early Cretaceous efforts to simplify the ‘over-split’ ichnotaxonomy of of China. On the contrary, we now know of about 70 Chinese tetrapod tracks (Lockley et al., 2013). One sites reported from most of the 31 provinces, regions outcome of this study has been to conclude that and municipalities of China. Here we summarize the Jurassic tetrapod ichnotaxonomy was even more over- data available from these sites and compare the split than Cretaceous ichnotaxonomy. Nevertheless results with summaries derived from other areas 34 Chinese tetrapod ichnospecies have been named to well-known for abundant Early Cretaceous tracksites date (Lockley et al., 2013, Table 1; Table 1 herein). As including Korea, North and South America and noted in the following sections work on important Europe. We also discuss the differences between data- tracksites in Korea, the Americas and Europe has bases obtained from different regions by different been ongoing at least since the 1980s, if not earlier methods. in some regions. However, due to the difference in Impetus for the present study derives from several size of study areas, geology and research methods sources. First, it is a contribution to the Jehol- (traditions), the emergent data have proved quite Wealden International Conference, held in England variable. in September 2013 (see acknowledgements). Second, is the opportunity to showcase the rapid development MATERIAL AND METHODS of Early Cretaceous tetrapod ichnology in China in the last decade. Third, the study provides an oppor- Despite the aforementioned studies that review the tunity to compare the most important Early Creta- distribution of ichnofaunas in China and East Asia, ceous ichnofaunas from China with those known from the potential data base is vast, especially when com- other parts of East Asia, the Americas, Europe and parative data from Korea, the Americas and Europe is elsewhere. As discussed, these databases are very included. Ideally a complete database should include variable and incomplete in some regions. a list of all sites, and the number of track types and trackways reported from each. While such data are available for some sites, reliable data are by no means PREVIOUS WORK readily available for all sites. This is to say nothing of The first attempts to summarize the fossil footprint the variability employed in naming various track record of China, in the English literature, was by morphotypes either at the ichnospecies, ichnogenus or Zhen et al. (1989, fig. 19.1) who identified a total of 22 less-precise higher taxonomic levels. Moreover the ‘principal dinosaur footprint localities’ of which only published record is always in need of re-evaluation, eight were reported as being Cretaceous in age. This as some sites are enlarged, others removed or dimin- number was more than doubled when Matsukawa, ished by erosion or human impact, and yet others Lockley & Li (2006) reported 52 principal sites from re-evaluated by re-naming or re-surveying the China, including 29 in the Cretaceous, as well as an various ichnotaxa, and their relative abundance. With additional 20 mostly Cretaceous sites elsewhere in increase interest in geoheritage studies, and the crea- East Asia. Between 1999 and 2006, much of this work tion of national and international geoparks and World was spear-headed by two of the present authors (MGL Heritage sites in areas with significant fossil footprint and MM) culminating in short reviews (e.g. Lockley & sites, efforts are underway to find consistent methods Matsukawa, 2009). Presently this work is being con- for evaluating the importance of tracksites, because tinued (2007-present) under the leadership of LX and such comparative analyses are required for such MGL, with continued participation by the other nominations and designations. Thus, several studies, authors. As noted below these lists are always under- pertaining to World Heritage site nominations have estimates, and always in need of updating. This is created lists of the globally most important tetrapod because they often deal only with principal sites, or tracksites based on a number of factors: size of site, treat previously defined tracksite regions, where number of trackways, diversity of track types, pres- several discrete sites occur in close proximity, as ervation quality, and other features. These factors single sites. Efforts to list tetrapod tracksites in cannot be discussed in detail here. However, it is China and East Asia have been fairly consistent, at important to note that many factors must be consid- least in style of presentation. The map produced by ered in measuring importance, including those listed Zhen et al. (1989) formed the basis of subsequent above. These factors may be of similar or different maps (Matsukawa et al., 2006; Lockley et al., 2012a) importance in evaluating sites for scientific study and and is again used here (Fig. 1). However, as noted for geoheritage designations. For example, large sites above, the number of tetrapod tracksites reported may appear high on the global list of importance, from China has increased rapidly in recent years and whereas small sites do not. Nevertheless, small sites is now in excess of 100, with about 70 being known may be of scientific significance and it is important to from the Cretaceous (Table 1). There have been recent include all sites in databases if possible. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 770–789 772 M. G. LOCKLEY Table 1. List of 72 tetrapod tracksites from China, referred to as Cretaceous in at least one published source. Note that some may be associated with the Jurassic–Cretaceous boundary and some may be Upper Cretaceous in age. Holotype occurrences also noted (light green shading; light grey in print). Thero, theropod; sauro, sauropod; ornith, ornithioschian; ptero, pterosaur; croc, crocodilian © 2014 The Linnean Society of London, Site Province Age Fm or Gp Thero Bird Sauro Ornith Ptero Croc Turtle Holotype 1 Tongfosi Jilin Cret Tongfosi x Ornithopod ET AL 2 Sijiazi Liaoning Tith-Ber Tuchengzi X Grallator ssatoi 3 Nanpachazu Liaoning Tith-Ber Tuchengzi x 4 KanJiaTun Liaoning Tith-Ber Tuchengzi X Pullornipes aureus .