Planatophyton gen. nov., a late Early or Middle Devonian euphyllophyte from Xinjiang, North-West China Philippe Gerrienne a , Brigitte Meyer-Berthaud b , Nan Yang c , Philippe Steemans a , Cheng-Sen Li c a PPP, Département de Géologie, Université de Liège, Allée du 6 Août, B18 Sart Tilman, B4000 Liège, Belgium b CNRS, Université Montpellier 2, UMR Botanique et Bioinformatique de l'Architecture des Plantes (AMAP), Montpellier F-34000, France c State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China abstract article info Article history: Received 5 March 2014 Received in revised form 13 May 2014 Accepted 15 May 2014 Available online 22 May 2014 Keywords: Devonian Euphyllophyte Multiveined leaf evolution Planar lateral branching system Possible rhizome China A new euphyllophyte, Planatophyton hujiersitense gen. et sp. nov., is described on the basis of adpression fossils collected from a late Early or Middle Devonian locality from the Hujiersite Formation in the Hujiersite area, Hoboksar County, North Xinjiang, North-West China. The plant is possibly rhizomatous and comprises main axes with alternately inserted lateral branching systems. All axis orders bear large triangular enations all over their surface. Lateral branching systems are up to six times dichotomous. Dichotomies in lateral branching sys- tems occur in the same plane, which results in bilaterally symmetrical, two-dimensionally branched organs, with limited overlapping between any segments. Distal segments in sterile lateral branching systems look slight- ly flattened and/or webbed. The ultimate segments of fertile lateral branching systems bear Psilophyton-like pairs of pendulous twisted sporangia. Anatomy and spores of the plant are unknown. The implications of the new plant for the early evolution of multiveined leaf are evaluated. © 2014 Elsevier B.V. All rights reserved. 1. Introduction For the last 50 years, China has been playing an increasingly impor- tant role in Devonian palaeobotany. The Lower Devonian deposits of the Yunnan province (SW China) have for example yielded impressive col- lections of early land plants such as the famous Posongchong flora (see detailed accounts in Yang and Li, 2009; Hao and Xue, 2013a), with major implications on our understanding of the biology and early evolu- tion of vascular plants. Potentially equally rich and diversified Devonian plant assemblages have also been recovered from several localities in North Xinjiang (NW China). Preliminary studies were issued during the previous century (Sze, 1960, 1961; Dou et al., 1983; Dou and Sun, 1985; Cai and Wang, 1995; Wang and Hao, 1996). Research on North Xinjiang floras has recently gained momentum, with the descriptions of various new taxa from the Middle Devonian Hujiersite Formation of West Junggar Basin (Wang et al., 2004; Wang, 2008; Xu and Wang, 2008; Xu et al., 2008; Fu et al., 2011; Xu, 2011; Xu and Wang, 2011; Xu et al., 2011a,b, 2012b, 2013). In this work, we describe Planatophyton hujiersitense gen. et sp. nov., a euphyllophyte at the trimerophyte grade of evolution collected from an as yet unpublished locality from the Hujiersite Formation in the Hujiersite area, Hoboksar County, North Xinjiang, NW China. The plant possesses Psilophyton-like pairs of pendulous twisted sporangia, but, unlike Psilophyton, its dichotomous lateral branching systems are clearly planate. The phylogenetic position of the new plant and its implication for the early evolution of multiveined leaf are evaluated; the general as- pect of the Hujiersite flora is also considered. 2. Geological settings and age More than 50 specimens were collected in 2006 during a fieldwork campaign organised by one of us (Li CS, Institute of Botany, Chinese Academia of Science). They come from a locality discovered in 1993 in the Hujiersite Formation located near Mongkelu, Hoboksar Mongol Autonomous County, Xinjiang, China (GPS 46°49′22″N, 86°40′33″E). Other plant fossils collected at the locality consist of fragmentary spec- imens of short length. They include poorly preserved decorticated stems of an undeterminable lycophyte and several specimens of Serrulacaulis sp. The locality is close to that of Xu (2011), where well preserved specimens of Serrulacaulis cf. furcatus Hueber & Banks were collected. The age of the Hujiersite fossiliferous beds has long been un- clear. The Hujiersite Formation was first attributed a Givetian (late Middle Devonian) age on the basis of lithological and biostratigraphical data (Cai and Wang, 1995; Lu, 1997; Wang et al., 2004; Xu et al., 2008; Fu et al., 2011; Xu et al., 2011a,b, 2012b, 2013). According to Xu (2011) and Xu et al. (2012a) however, a preliminary result from a palynological study of the fossiliferous beds of the Xu (2011) and Xu et al. (2011a,b) locality suggested an Eifelian age. More recently, the Serrulacaulis bed at the base of the Upper Member of the Hujiersite Formation has been attributed a late Emsian (Early Devonian) or an Eifelian (Middle Review of Palaeobotany and Palynology 208 (2014) 55–64 http://dx.doi.org/10.1016/j.revpalbo.2014.05.005 0034-6667/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Review of Palaeobotany and Palynology journal homepage: www.elsevier.com/locate/revpalbo