Pagiophyllum is a form genus of extinct conifers with scale-like, spirally arranged leaves, widely distributed from the Late Permian to the Late Cretaceous. Due to its leaf morphology resembling several conifer families (e.g., Cheirolepidiaceae, Cupressaceae, Araucariaceae), its taxonomic placement has long been uncertain. Although some species have been assigned to the extinct family Cheirolepidiaceae, most fossils are preserved as isolated leafy shoots lacking cuticular details and reproductive structures, hindering definitive natural classification and understanding of their ecological adaptations.
Recently, Prof. WANG Yongdong, from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, and Associate Professor ZHOU Ning from the Department of Geology, Northwest University, in collaboration with other colleagues from Anhui University of Science and Technology, as well as Chengdu University of Science and Technology, conducted a systematic palaeobotanical study on well-preserved Pagiophyllum maculosum Kendall fossils from the Lower Jurassic in the Zigui Basin, western Hubei Province, South China. This study marks the first discovery of this species in China, yielding materials with leafy shoots bearing cuticles, male and female cones. The results has been published in the international journal Review of Palaeobotany and Palynology.
Initially reported only from the Middle Jurassic of Yorkshire, UK, Pagiophyllum maculosum lacks definitive records of cuticles and reproductive organs owing to poor preservation. Here, the research team utilize optical, fluorescence, and scanning electron microscopy, alongside micro-CT, to elucidate the morphology and anatomy of its vegetative shoots, female and male cones, and epidermal structures. The study shows that the leaves of P. maculosum are triangular to ovoid, helically and imbricately arranged (Figs. 1-2). The abaxial leaf surface bears stomatal rows with sunken stomata surrounded by 4-6 subsidiary cells; epidermal cells are irregularly polygonal (Figs. 3-4). The female cone is elliptical, approximately 2.5 cm long, consisting of an estimated 36-40 helically arranged bract-scale complexes (Figs.2). The male cone is subspheroidal, about 6.5 mm in diameter, with peltate microsporophylls producing typical Classopollis-type pollen (Fig.4). Based on these morphological and anatomical features, the research team presents a whole-plant reconstruction of P. maculosum (Fig.5).
Different Pagiophyllum species exhibit leaf morphological characteristics that are convergent with those of the families Cupressaceae, Taxodiaceae, Araucariaceae, and Cheirolepidiaceae. This has led to a complex taxonomic history, with Pagiophyllum species being assigned to different families. To assess the morphological similarities among the related leaf specimens, a hierarchical clustering analysis was performed based on a set of discrete character states (Fig.6). The analysis was conducted based on a morphological matrix of 18 characters for 29 fossils and 6 extant species from Taxodiaceae and Araucariaceae. The clustering analysis confirms that the leaf architecture of Pagiophyllum maculosum is clearly assignable to the Brachyphyllum-type morphospace. Its strong morphological affinity with Brachyphyllum and Elatides supports its inclusion within a coherent eco-morphological group. This classification is consistent with earlier studies that place P. maculosum within the Cheirolepidiaceae. Therefore, this fossil material provides direct evidence for the natural taxonomic placement of this form genus and offers new insights into the whole-plant morphology of Jurassic Cheirolepidiaceae.
Notably, P. maculosum exhibits typical xeromorphic features, including thick cuticles, sunken stomata, and reduced free leaf parts. Furthermore, the plant assemblage from the same horizon is dominated by gymnosperms such as ginkgoaleans, bennettitaleans, and conifers, with ferns being exceptionally rare. This dominance of gymnosperms, coupled with the xeromorphic traits of P. maculosum, suggests an arid or semi-arid climate during the depositional period. These findings provide important evidence for understanding Early Jurassic paleoclimate and the ecological adaptations of cheirolepidiaceous conifers.
This research was jointly funded by the National Natural Science Foundation of China, and the National Key Research and Development Program of China.
Reference: Ning Zhou*, Yongdong Wang*, Yuanyuan Xu, Pengcheng An, Ziheng Wu. Whole-plant reconstruction of Pagiophyllum maculosum (Cheirolepidiaceae) from the Early Jurassic of China: Insights from new fossil material. Review of Palaeobotany and Palynology, 348 (2026) 105540. https://www.sciencedirect.com/science/article/pii/S0034666726000424.
Fig. 1. Fossil specimens of Pagiophyllum maculosum from the Lower Jurassic in Zigui of Hebei Province, China
Fig. 2. Female cone of P. maculosum
Fig.3. Fluorescence micrograph of P. maculosum leaf cuticles
Fig. 4. P. maculosum (A–D) Scanning electron micrograph of the cuticle, showing epidermal cells and sunken stomata; (E, F) Light microphoto of Classopollis pollen
Fig. 5. Restoration of P. maculosum with leafy shoots, male cone, female cone, seed scale and Classopollis-type pollen
Fig.6. Hierarchical clustering based on a set of discrete character states for the potential fossil relatives and extant conifers, with extant species indicated by an asterisk (*). Different colors represent distinct clusters based on morphological similarity
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