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Searching for land refugia becomes imperative for human survival during the hypothetical sixth mass extinction. Studying past comparable crises can offer insights, but there is no fossil evidence of diverse megafloral ecosystems surviving the largest Phanerozoic biodiversity crisis. Here, we investigated palynomorphs, plant, and tetrapod fossils from the Permian-Triassic South Taodonggou Section in Xinjiang, China. Our fossil records, calibrated by a high-resolution age model, reveal the presence of vibrant regional gymnospermous forests and fern fields, while marine organisms experienced mass extinction. This refugial vegetation was crucial for nourishing the substantial influx of surviving animals, thereby establishing a diverse terrestrial ecosystem approximately 75,000 years after the mass extinction. Our findings contradict the widely held belief that restoring terrestrial ecosystem functional diversity to pre-extinction levels would take millions of years. Our research indicates that moderate hydrological fluctuations throughout the crisis sustained this refugium, likely making it one of the sources for the rapid radiation of terrestrial life in the early Mesozoic. 

The Capitanian–lower Wuchiapingian lower and upper Quanzijie low-order cycles (QZJ LCs) in Bogda Mountains, NW China, containevidence of mountain glaciation and loess deposition in eastern Kazakhstan Plate. They occur in Zhaobishan (ZBS), Tarlong-Taodonggou (TL-TDG), and Dalongkou (DLK) areas, ~100 km apart. The lower QZJ LC overlies a regional unconformity, consists of conglomerate at ZBS at foothills of ancestral north Tianshan and Calcisol, mudrock, sandstone, and conglomerate at TL-TDG andDLK in the basin, and is 1-10s m thick. The basinal deposits are upward-fining meandering stream deposits. In ZBS, fining-upward successions from imbricated boulder–pebble conglomerates to minor sandstones with erosional bases are braided stream deposits.Of 135 randomly-counted cobbles and boulders, 80% are faceted penta-, hexa-, and hepta-hedrons with rounded edges; 75% have atleast one flat face; 60% one concave face (60%); 93% smooth, shiny, and smeared faces; 56% 1–3 sets of parallel to non-parallel striations; and 57% one or more grinding pits, indicating a glacial origin. In contrast, the upper QZJ LC is 60-160 m thick in the basinand 205 m in ZBS. Basinal deposits consist of massive mudstone with a consistent silt-size distribution, interspersed with lenticular upward fining conglomerate to sandstone, interpreted as loess and ephemeral braided stream deposits, respectively. In ZBS, the upper QZJ LC contains mainly upward fining conglomerate–sandstone successions of coarse-grained meandering stream deposits.Few ostracod-bearing shales and well rounded and cross-stratified sandstones are lacustrine and eolian deposits, respectively.Gravels are mainly pebble–granule. 22 counted cobbles are similar to those in lower QZJ and 77% have 1–3 sets of striations, suggesting a dominantly proglacial fluvial setting. Petrified woods with distinct frost rings are common in the QZJ, indicating a freezing upland condition. The basal unconformity signifies tectonic uplift and erosion during closure of Paleo-Asian Ocean. Growth of north Tianshan in an icehouse climate promoted formation of alpine glaciers, which supplied copious fluvial sediments of the lower QZJ.Glacial retreat exposed previous sediments to source the loess accumulated in the basin, but proglacial fluvial deposition persisted inZBS until early Wuchiapingian. 

Exceptionally well-preserved impression fossils of Cyrillopteris (ex. Odontopteris) orbicularis (Halle) comb. et emend. nov. have been described from the lower part of the middle–upper Permian Upper Shihezi (Upper Shihhotse) Formation in Yangquan City, Shanxi Province, North China. For the first time, this typical Cathaysian seed fern is confirmed to have a bipartite frond with two bipinnate branches, comparable with that of C. genuina (Grand’Eury) Laveine et Oudoire from the Pennsylvanian of France. Entire-margined cyclopteriod elements occur in the proximal portion of the long petiole. With increasing proximity of the bifurcation, the cyclopteroid elements progressively differentiate into pinnae with individual pinnules. True intercalary pinnules, which would be fully inserted on the primary rachides, are not present. Characteristics of our new specimens provide new information on the frond architecture of C. orbicularis (Halle) comb. et emend. nov., and allow a relatively complete circumscription of the overall features of this taxon, an emendation of the species diagnosis, and the presentation of an accurate frond reconstruction. Specimens of C. orbicularis comb. et emend. nov. are preserved with mesophytes and xerophytes from the same interval, demonstrating the vegetation in the research area grew under a seasonal subhumid to semiarid climates during the late Guadalupian. 

ABSTRACT The Bogda Mountains, Xianjiang Uygur Autonomous Region, western China, expose an uppermost Permian–Lower Triassic succession of fully continental strata deposited across three graben (half graben) structures in the mid-paleolatitudes of Pangea. A cyclostratigraphy scheme developed for the succession is subdivided into three low-order cycles (Wutonggou, Jiucaiyuan, Shaofanggou). Low-order cycles are partitioned into 1838 high-order cycles based on repetitive environmental changes, and their plant taphonomic character is assessed in > 4700 m of high-resolution, measured sections distributed across ∼ 100 km. Four taphonomic assemblages are represented by: permineralized wood (both autochthonous and allochthonous), megafloral adpressions (?parautochthonous and allochthonous) identifiable to systematic affinity, unidentifiable (allochthonous) phytoclasts concentrated or disseminated on bedding, and (autochthonous) rooting structures of various configurations (carbon films to rhizoconcretions). Their temporal and spatial occurrences vary across the study area and are dependent on the array of depositional environments exposed in any particular locality. Similar to paleobotanical results in other fully continental basins, megafloral elements are rarely encountered. Both wood (erect permineralized stumps and prostrate logs) and adpressions are found in < 2% of meandering river and limnic cycles, where sediment accumulated under semi-arid to humid conditions. The absence of such assemblages in river-and-lake deposits is more likely related to physical or geographical factors than it is to an absence of organic-matter contribution. With such a low frequency, no predictable pattern or trend to their occurrence can be determined. This is also true for any horizon in which rooting structures are preserved, although paleosols occur in all or parts of high-order cycles developed under arid to humid conditions. Physical rooting structures are encountered in only 23% of these and are not preserved equally across space and time. Allochthonous phytoclasts are the most common taphonomic assemblage, preserved in association with micaceous minerals on bedding in fine-grained lithofacies. The consistency of phytoclast assemblages throughout the succession is empirical evidence for the presence of riparian vegetation during a time when models propose the catastrophic demise of land plants, and does not support an interpretation of vegetational demise followed by long-term recovery across the crisis interval in this basin. These mesofossil and microfossil (palynological) assemblages offer the best opportunity to understand the effects of the crisis on the base of terrestrial ecosystems. 

A silicified trunk,Zhuotingoxylon liaoiWan, Yang, Wang, Liu et Wang gen. et sp. nov., is described from the uppermost part of Guodikeng Formation in South Taodonggou section, Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China. It is characterized by a solid pith, endarch primary xylem and pycnoxylic wood. The pith is composed of parenchyma and sclereids. Radial walls of primary xylem tracheids have spiral and scalariform thickenings. Secondary xylem consists of thick‐walled tracheids and parenchymatous rays. Uniseriate rounded pits with oval apertures are distributed on radial tracheidal walls separately. Cell walls of rays are homogeneous and smooth. Rays are 1–10 cells high in tangential section. Cross‐field pits are cupressoid. There are 1–4 bordered pits with slit‐like to oval apertures in each cross‐field. Based on the anatomical features of the pith and xylems, it is proposed that the new stem has a coniferous affinity. The new fossil stem adds to the knowledge of vascular plant diversity close to the Permian–Triassic boundary.