Issue 4,2025 Table of Contents

1 Cambrian Miaolingian microbial reefs dominated by calcified microbes at the Jinzhou section, Dalian, Liaoning Province

GONG Yun-yun , NI Sheng-li

2025, 64(4):379-398. DOI: 10.19800/j.cnki.aps.2025024

[Abstract](164) [HTML](0) [PDF 10.49 M](72)

Abstract:
The Cambrian Miaolingian microbial reefs exposed at the Jinzhou section, Dalian, Liaoning Province were developed in the highstand system tract of third-order depositional sequences. Macroscopically, these microbial reefs lack distinctive internal structures and mainly consist of micrites, forming carbonate rock complexes with associated stromatolites, oolitic grainstones, and oncolitic grainstones. Microscopically, observations under a polarizing microscope reveal the presence of microclots, calcified microbes, benthic oolites, and various micritized structures within the microbial reefs. The calcified microbes include Girvanella, Renalcis, Tarthina, Epiphyton, and possible Angulocellularia. Girvanella exhibits four growth habits, and both Girvanella and Renalcis aggregates are present. Variations in the composition of calcified microbial groups in different layers may be related to the changes of sedimentary environments. The calcified microbes in the study area, together with the micritized or dolomitized calcified microbes and associated pyrites in different microbial structures, indicate that both photoautotrophs and heterotrophic sulfate-reducing bacteria played important roles in the formation of the microbial reefs. These features also suggest that the preservation of calcified microbes is not only controlled by early lithification but also is closely linked to heterotrophic bacterial activities during diagenesis. The Cambrian Miaolingian microbial reefs at the Jinzhou section provide an example of reefs dominated by calcified microbes.

2 Ontogenetic character analysis of the Middle Triassic Lariosaurus youngi (Reptilia: Sauropterygia) from Guizhou

MA Xiao-han , QIN Yan-jiao , HE Xiao , YU Mei-yi , LUO Yong-ming , TIAN Li , YANG Yu-ning

2025, 64(4):399-410. DOI: 10.19800/j.cnki.aps.2025015

[Abstract](149) [HTML](0) [PDF 18.16 M](206)

Abstract:
In this study, the key diagnostic characters of the Middle Triassic Lariosaurus youngi are re-evaluated based on comprehensive morphometric and osteological analyses of four newly discovered fossil specimens from the Xingyi fauna of Guizhou, together with previously described materials. The diagnostic characters reassessed include: (1) a pineal foramen positioned within a parietal trough; (2) the presence of a jugal; (3) an upper temporal fenestra with a longitudinal diameter 2 to 2.4 times that of the orbit; and (4) an interclavicle lacking a posterior stem. Ontogenetic stages of L. youngi—juvenile, subadult, and adult—are reconstructed. Adult individuals are characterized by a snout-vent length (SVL) exceeding 1000 mm and extensive skull fusion. Juvenile individuals (SVL ＜ 500 mm) exhibit reduced skull fusion, incomplete limb ossification, and comparatively simplified skeletal structures. Subadult individuals display intermediate morphological conditions, with skeletal features transitional between those of juveniles and adults. The relative lengths of the humerus and femur, along with the degree of epiphyseal expansion, may serve as reliable indicators of sexual dimorphism in L. youngi. Furthermore, the progressively higher humerus-to-femur length ratios observed from juveniles to adults suggest an ontogenetic enhancement of swimming capability.

3 Macroevolution of corals across the Triassic–Jurassic transition: morphological disparity, diversity response, and recovery patterns

ZHU Xiu-ping , LIANG Kun , BO Jing-fang , HAN Zhong , RAO Xin , LIAO Wei-hua

2025, 64(4):411-429. DOI: 10.19800/j.cnki.aps.2025031

[Abstract](138) [HTML](0) [PDF 19.94 M](69)

Abstract:
The mass extinction event at the Triassic–Jurassic boundary (~201 million years ago) profoundly impacted marine ecosystems. Current research indicates that massive volcanic eruptions of the Central Atlantic Magmatic Province (CAMP) served as the primary trigger for this event. The resulting environmental stresses—including perturbations to the carbon cycle, drastic sea-level fluctuations, and ocean acidification—led to a dramatic decline in marine benthic biodiversity. Among the most severely affected groups were reef-building organisms such as scleractinian corals, reef-dwelling sponges, and bivalves. During this extinction event, corals exhibited distinct phased extinction patterns, with a generic extinction rate of 56.41% and two extinction peaks occurring in the late Rhaetian and late Pliensbachian stages. Environmental analyses indicate that reduced seawater carbonate ion (CO?2?) concentrations and declining aragonite saturation (Ωarag) were critical limiting factors for coral survival. These changes directly inhibited the calcification capacity of reef-building corals and disrupted their symbiotic relationships with zooxanthellae, ultimately leading to the preferential extinction of highly integrated corals (i.e., complex taxa dependent on symbiosis). Concurrently, associated reef-dwelling sponges experienced one of the most severe extinction events in the Phanerozoic. Post-extinction coral recovery displayed clear phasic characteristics. During the early Hettangian, more resilient solitary corals with low levels of morphological integration initiated the recovery process, driving the initial rebound of coral diversity. In contrast, the full recovery of highly integrated reef-building corals was delayed until the Sinemurian. Spatially, corals exhibited a notable high-latitude refuge effect: reef-building corals were predominantly distributed in high-latitude regions (＞30°) and began migrating toward mid- to low-latitudes (25°–35°) areas only in the late Pliensbachian, without crossing into equatorial zones. It was not until environmental conditions stabilized during the Bajocian that reef-building corals re-established flourishing communities in equatorial regions, marking the complete restoration of structural complexity in coral-reef ecosystems.

4 Taphonomic characteristics of an Upper Cretaceous dinosaur fossil-rich layer along the west bank of the Erlian Salt Lake, Inner Mongolia, and their paleoecological implications

MA Fei-min , ZHANG Chen , LIU Jian-jun , ZANG Hai-long , YAO Han , XING Hai

2025, 64(4):430-443.

[Abstract](162) [HTML](0) [PDF 22.50 M](125)

Abstract:
Outcrops of the Upper Cretaceous Iren Dabasu Formation along the west bank of the Erlian Salt Lake have yielded abundant disarticulated dinosaur fossils that display taphonomic features characteristic of a hydraulically accumulated lag deposit. This discovery is significant for reconstructing the composition of the assemblage and the taphonomic and sedimentary history of the dinosaur community found in this area. Based on skeletal measurements and taphonomic data collected from the fossil-rich layer during fieldwork conducted in 2014 and 2015, more than 50% of the specimens from the bonebed are attributed to the early-branching hadrosauroid Bactrosaurus johnsoni, suggesting herding behavior of this species in life. Following catastrophic mass mortality events, the dinosaur community was strongly affected by the carcass decomposition, mechanical bone breakage, and physical weathering, ultimately resulting in a vertebrate bonebed mono-dominated by Bactrosaurus. Paleocurrent orientations are random and variable, reflecting a relatively chaotic process of hydraulic transportation of bones. Hydraulic sorting played only a minor role in bone transportation and burial. The age profile of the Bactrosaurus population is dominated by nestling and juvenile individuals, strongly indicating an attritional mortality pattern and suggesting population segregation between hadrosauroid juveniles and adults.

5 Cones and leaves of Tsuga from the Lower Miocene of Inner Mongolia and their paleoclimate implications

XIAO Liang , YANG Fan , WANG Hong-yu , GUO Li-yan , JI De-shuang , ZHOU Min , YUAN Yu-huan , DING Wen-xue , YANG Xue-lin , LI Xiang-chuan

2025, 64(4):444-459. DOI: 10.19800/j.cnki.aps.2025008

[Abstract](172) [HTML](0) [PDF 13.13 M](70)

Abstract:
Tsuga Carr. is a genus of evergreen trees in Pinaceae, with disjunct distributions in warm, humid ecosystems between East Asia and North America. In this study, we describe three cones and two leaves of Tsuga collected from the Lower Miocene Hannuoba Formation in Zhuozi County, central Inner Mongolia, China. This report represents the first time that these two organs of Tsuga have been found from the same geological horizon and locality. The morphology of the three-dimensionally preserved cones was examined using Micro-CT scanning, while the microstructures of the leaves were studied via cuticle analysis. Through detailed comparisons with extant Tsuga species and other related fossil taxa, these three cone specimens are assigned to a new species, Tsuga zhuoziensis sp. nov., and the two leaves are assigned to Tsuga cf. T. dumosa. Morphologically, the new species is most similar to extant Tsuga dumosa, suggesting a close phylogenetic relationship. Based on the climate preferences of Tsuga dumosa and the climate data of previously reported Early Miocene fossil relatives from Zhuozi, it is inferred that the mean annual temperature during the Early Miocene in this region was approximately 6–10℃ higher than that of today, with annual precipitation exceeding 700 mm. This indicates that the Early Miocene paleoclimate of Zhuozi was significantly warmer and wetter than that of the present. In conjunction with Tsuga fossils from the Early Miocene of Weichang, Hebei Province, this study further supports the inference that North China experienced a warmer and more humid climate during the Early Miocene than today.

6 A review of the early Cambrian tubiform fossil Anabarites: taxonomy and spatiotemporal distribution

ZHU Xi-yu , PANG Yan-chun , LI Guo-xiang , LI Xin-yang , XIANG Fan , HE Yang-jian , ZHANG Meng-shao , HU Qiang , ZHAO Yuan-ming , MA Yi-ding

2025, 64(4):460-481. DOI: 10.19800/j.cnki.aps.2024040

[Abstract](156) [HTML](0) [PDF 2.20 M](65)

Abstract:
The tubiform fossil Anabarites, characterized by triradial symmetry, is a common component of early Cambrian small shelly fossils (SSFs). Although its record may extend into terminal Ediacaran strata, typical species such as Anabarites trisulcatus first appear at the base of the Cambrian Fortunian and serve as key index fossils for the Anabarites trisulcatus-Protohertzina anabarica Assemblage Zone of the lower Fortunian in South China. Owing to extensive synonymy problems, this study reevaluates the status of all 41 species previously assigned to the genus Anabarites. Through a comprehensive analysis of diagnostic characters, including tubular morphology, development of longitudinal grooves, and variability in growth angles, we propose a revised classification scheme recognizing 14 accepted species. Spatiotemporal distribution analysis further reveals three distinct evolutionary stages: occurrence, diversification, and decline. The genus underwent its initial radiation in the Fortunian Age, reaching peak species diversity and maximal geographic distribution by the late Fortunian. A pronounced decline began in Cambrian Stage 2, marked by reduced abundance and contracted geographic range. This genus gradually went extinct during Stages 3–4, with occurrences restricted to a single region. Evolutionary trends in morphology show a clear shift from simple to more complex forms over time: tubular symmetry transitions from triradial to hexaradial, longitudinal surface grooves deepen progressively, and development of growth lines becomes increasingly pronounced.

7 An overview of the development of palaeontology textbooks in China

ZHANG Qian-qi , SONG Hai-jun , TIAN Ning , ZHANG Hai-chun

2025, 64(4):482-501. DOI: 10.19800/j.cnki.aps.2025018

[Abstract](149) [HTML](0) [PDF 3.68 M](64)

Abstract:
The compilation of palaeontology textbooks in China spans over 150 years, with at least 354 titles produced and 135 formally published according to current statistics. Based on an examination and analysis of the bibliographic records of extant palaeontology textbooks from universities and research institutions, the compilation history can be divided into six stages: (a) the Germination Period (1871–1951), dominated by translations of Western textbooks; (b) the Differentiation and Development Period (1952–1965), marked by the initial formation of a localized system; (c) the Stagnation Period (1966–1976), during which publication of textbooks nearly ceased; (d) the Diversification and Growth Period (1977–1999), characterised by the rapid emergence of specialized subdisciplinary textbooks; (e)the Deep Integration Period (2000–2011), characterised by closer integration with historical geology; and (f) the New Era (since 2012), characterised by significant trends toward internationalization. This study reveals that the evolution of palaeontology textbooks parallels that of geology textbooks in China, following the trajectory from importation to localization and ultimately to internationalization. However, challenges remain, including outdated contents (with some textbooks failing to incorporate key findings by Chinese palaeontologists during the past 30 years) and insufficient coverage of specialized subdisciplines. Future efforts should focus on integrating frontier research results, modernising visual presentation (e.g., full-colour and artistic illustrations), and establishing dynamic revision mechanisms to enhance the scientificity and global impact of palaeontology textbooks.

8 A review of the morphology and function of the dinosaur hyolaryngeal apparatus

YANG Yun-feng

2025, 64(4):502-518. DOI: 10.19800/j.cnki.aps.2025034

[Abstract](150) [HTML](0) [PDF 4.28 M](151)

Abstract:
The hyolaryngeal apparatuses of dinosaurs are important in studying dinosaur biology and they play a significant role in understanding multiple aspects of their functions, behaviors, ecology, and evolution. Although fossils of hyolaryngeal apparatuses of most major dinosaur clades have been reported, in most specimens only the first pair of ceratobranchials is preserved while other elements are rarely documented. Consequently, related research has been limited by the scarcity of well-preserved specimens. Studies of extant reptiles and birds indicate that hyolaryngeal apparatus is important for several functions in dinosaurs, including feeding, breathing, and acoustic behavior. These functions likely influenced the evolution of diet and vocalization in non-avian dinosaurs and birds. The function and evolution of dinosaur hyolaryngeal apparatuses are also strongly associated with the origin and evolution of avian syrinx. Given its importance for understanding dinosaur functional anatomy, ecology, and evolution, further research is necessary. Progress in this field is currently constrained not only by the limited availability of fossil materials, but also by the lack of studies with broader scope or greater analytical depth. To address these challenges, we propose focusing on several key areas to advance understanding of the dinosaur hyolaryngeal morphology, function, and evolution: (1) collecting more specimens with well-preserved hyolaryngeal structures; (2) providing more detailed descriptions, accurate identifications, and comprehensive comparisons with existing specimens; and (3) conducting advanced analyses using multiple approaches, including comparative anatomy, quantitative methods, and phylogenetic analysis. In this paper, we summarize current research on the dinosaur hyolaryngeal apparatus and further discuss and infer the morphological and functional characteristics of select taxa. We also provide practical suggestions for addressing major challenges in the field, laying a foundation for future research.

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