DOI: 10.15468/ve43zw
title: Presence of the Jehol Biota turtle Ordosemys liaoxiensis in the Early Cretaceous Hengtongshan Formation of southern Jilin Province, China

description: This dataset contains the digitized treatments in Plazi based on the original journal article Zhou, Chang-Fu, Wu, Wen-Hao, Rabi, MAErton (2019): Presence of the Jehol Biota turtle Ordosemys liaoxiensis in the Early Cretaceous Hengtongshan Formation of southern Jilin Province, China. Fossil Record 22 (2): 57-64, DOI: 10.5194/fr-22-57-2019, URL: http://dx.doi.org/10.5194/fr-22-57-2019Abstract. Recently, a vertebrate assemblage of the Jehol Biota has been reported from the Early Cretaceous Hengtongshan Formation of Xingling Town, Meihekou City, Jilin Province, China. It is dominated by the fishes Lycoptera and Sinamia and the sinemydid turtle Ordosemys. Here, we describe the turtle specimens and referral to Ordosemys liaoxiensis, otherwise known from the older Yixian Formation of the Jehol Biota. It is characterized by a subcircular shell, wide vertebral scales, well-developed plastral fenestrae, and a major contribution from the xiphiplastra to enclose the hypo-xiphiplastral fenestra. As the first Mesozoic turtle of Jilin Province, this record represents the first tetrapod to indicate the presence of the Jehol Biota in the region. Given the geographic and temporal distance from the Yixian Formation, future collections from the Hengtongshan Formation have good potential for evaluating spatiotemporal patterns of the Jehol Biota.1 IntroductionThe Jehol Biota of northeastern China (western Liaoning and conjoint areas) is renowned for providing exceptional insights into an Early Cretaceous ecosystem through its exquisite preservation of plant, invertebrate, and vertebrate fossils (e.g., Zhou et al., 2003; Pan et al., 2013). In the field, the Jehol Biota is typically recognized by the presence of the Eosestheria (crustacean)– Ephemeropsis trisetalis (mayfly insect)– Lycoptera (fish) community (T. Shao et al., 2017). Freshwater sinemydid turtles are among the most common tetrapod fossils of the Jehol Biota, which makes their biostratigraphic potential of interest (e.g., Ji, 1995; Tong et al., 2004; Zhou, 2010a, b; Zhou and Rabi, 2015; S. Shao et al., 2017, 2018; Li et al., 2019). However, these fossil turtles have been less commonly collected outside the typical western Liaoning area of the Jehol Biota (e.g., Ma, 1986; Li et al., 2015; Li and Tong, 2017; Wu et al., 2018). Recently, as the first record of the Mesozoic turtles from Jilin Province, the sinemydid Ordosemys has been reported from the Early Cretaceous Hengtongshan Formation of Xingling Town, Meihekou City (Wu et al., 2018). This material has not been described yet, and its species-level taxonomy awaits clarification. In this study, we describe this material, together with other two specimens, and clarify their taxonomic status. We show that these turtles represent the first tetrapod evidence for the presence of the Jehol Biota in the Hengtongshan Formation. Previous studies correlated the Hengtongshan Formation with the Jiufotang Formation of the Jehol Biota of western Liaoning and conjoint areas based on radiometric dating (119–123 Myr; Y. Chen et al., 2008; Sui and Chen, 2012; J. Chen et al., 2016) and biostratigraphic data (e.g., Lycoptera, Ephemeropsis, Eosestheria, Huashia, Diestheria, and Orthestheria) (e.g., JBGMR, 1982; Chang et al., 2009; Wu et al., 2018).The sinemydid turtle Ordosemys has a broad paleogeographic distribution in northern China (e.g., Danilov and Parham, 2007; Li et al., 2019). Three species are widely accepted, including the type species Ordosemys leios from the Ordos Basin of Inner Mongolia and Mengyin Basin of Shandong (Brinkman and Peng, 1993; Brinkman and Wu, 1999; Li et al., 2019), O. liaoxiensis from the Yixian Formation of western Liaoning (e.g., Ji, 1995; Tong et al., 2004), and O. brinkmania from Junggar Basin of Xinjiang (Danilov and Parham, 2007). Ordosemys donghai (i.e., Manchurochelys donghai, Ma, 1986) as recombined by Brinkman et al. (2008) from Heilongjiang, is possibly excluded from Ordosemys in lacking the typical generic features (Li et al., 2019).