DOI: 10.5061/dryad.d51c5b042
title: A new Late Devonian flora from Sonid Zuoqi, Inner Mongolia, northeastern China

description: The Silurian and Devonian plant fossil record is the basis for our
 understanding of the early evolution of land plants, yet our appreciation
 of early global phytogeographic evolution has been constrained by the
 focus of most studies on deposits from Europe, North America, and more
 recently South China. Devonian plants have been rarely recorded from
 northeastern China, and among previous records, few plants have been
 illustrated and formally described. In this article, megafossil plants
 representing a Late Devonian-aged (probably Famennian) flora are described
 from a locality at northern Sonid Zuoqi, Inner Mongolia, NE China. The
 flora includes Melvillipteris sonidia new species, Archaeopteris sp., and
 fragments of some other plants. The new plant shows main axes and two
 orders of lateral branches. The first-order branches of this plant show a
 typical zigzag appearance and are borne in pairs on main axes.
 Second-order branches are straight or slightly flexed, and are borne
 helically or alternately on first-order branches. Sterile ultimate
 appendages and fertile structures of M. sonidia n. sp. are borne
 alternately on second-order branches. An associated palynological
 assemblage, as well as U-Pb ages of detrital zircon grains from adjacent
 horizons, are also reported, indicating a Late Devonian age in accord with
 the megafossil plants. The present study contributes to our appreciation
 of the Devonian floristic diversity of the Xing’an Block, and, through our
 review of the record of early vascular plants from NE China, more broadly
 to the understanding of the mid-latitude vegetation of the Northern
 Hemisphere during the Late Devonian.
description: One sample of lithic
 wacke (PM90TW13) from bed-13 of section PM90 was collected for detrital
 zircon dating. Zircon grains were separated using conventional heavy
 liquid and magnetic techniques at the Laboratory of Hebei Institute of
 Regional Geology and Mineral Resources Survey, then were mounted in epoxy
 and polished for cathodoluminescence (CL) imaging at the Inner Mongolia
 Key Laboratory of Magmatic Mineralization and Ore-prospecting (IMLM),
 China. Zircon U-Pb dating was
 conducted by using Laser ablation-Multicollector-Inductively coupled
 plasma-Mass spectrometry (LA-MC-ICP-MS) at IMLM. The zircon standard GJ-1
 was used to calibrate U-Th-Pb ratios. Spot size for data collection was
 30 μm. Off-line inspection and integration of background and analysis
 signals, and time-drift correction and quantitative calibration for trace
 element analyses and U-Pb dating were performed by using ICP-MS DataCal
 (Liu et al., 2008). The errors for individual U-Pb analyses are presented
 with 1σ error and uncertainties in grouped ages are quoted at the 90%
 level (1σ). Age calculation and harmonic plot drawing were completed by
 Isoplot 3.0 (Ludwig, 2003). Further detailed descriptions of the
 instrumentation and analytical procedure for the LA-MC-ICP-MS zircon U-Pb
 can be found in Hou et al. (2009).
description: Detrital zircon U-Pb
 dating of a sample from bed-13 at the section PM90, Dalai Sumu Town,
 northern Sonid Zuoqi, Inner Mongolia, China.