Conference Agenda

The assembly of the volant bird body plan from the ancestral bulky dinosaurian condition is an enduring topic of evolutionary biology, including multiple instances of convergence and homology-related traits that contribute to the refinement of the flight capability. As the basic system, the body plan stands out from all these changes in demonstrating pronounced decrease in body size and proportionately elongation of the forelimb. Given the scaling relationships of limb and body size, changes of the former are likely clouded by changes of the entire body size. But changes of individual limb element, which provide the direct materials for natural selection, are essential to comprehend branch and lineage specific evolutionary patterns across the transition from terrestrial to volant theropods. Here we analyze the patterns of morphological disparity and evolutionary rate of appendicular limbs along avialan stem lineages using phylogenetic comparative approaches. Contrary to the traditional wisdom that the evolutionary innovation like flight would promote and accelerate evolvability, our results show a shift to low disparity and decelerated rate near the origin of birds that is largely ascribed to the evolutionarily constrained forelimb. Taken together, the recovered patterns of disparity and rate of appendicular limb evolution demonstrate how the early avialan bauplan has been shaped deeply by natural selection driven by powered flight.

This study investigates a non-marine ostracod fauna recovered from the Lisangou Formation of the Guyang Basin, encompassing twelve species belonging to ten genera: Cypridea unicostata, Cypridea sp., Candona spp., Mongolianella sp., Djungarica sp., Rhinocypris cf. jurassica, Ziziphocypris costata, Lycopterocypris cf. infantilis, Damonella cf. circulata, Timiriasevia sp., Darwinula? custella. Among these, the species C. unicostata is widely distributed in Hauterivian to Albian strata; Z. costata is found in Aptian to ?Danian non-marine strata, L. infantilis and D. circulata are widely distributed in Hauterivian to Albian non-marine strata. Consequently, based on the ostracod biostratigraphic correlation, the Lisangou Formation is mainly Aptian but may extend down to Hauterivian.

In this study, the ontogeny features of the Cretaceous fossil species Darwinula? custella of Darwinuloidea were identified for the first time. This also marks the first record of juvenile fossils of Cretaceous darwinuloideans. The family Darwinulidae has garnered significant interest over the past decade due to its potential status as one of only three "ancient asexual" groups in the animal kingdom. It has been suggested that the group has been reproducing asexually for over 200 million years due to the lack of male fossils in Mesozoic sediments. However, this assertion has been challenged by the discovery of rare males in one existing darwinulid species. Our new fossil material of Darwinuloidea, which shows its ontogeny, may provide fossil evidence for investigating whether the family Darwinulidae is indeed a truly "ancient asexual" group.

Acknowledgments. This study supported by the National Natural Science Foundation of China (42372022, 42481540217).

The present work is dealing with biochronostratigraphic record of species of ostracodes recovered from Maracangalha Formation, Itaparica, Bahia State. After a detailed field work in two outcrops at Itaparica island, respectively named Gameleira and Manguinhos beaches, nine species of Ostracoda were recovered: Paracypridea brasiliensis, Cypridea ventronodata, Cypridea vulgaris, Theriosynoecum isoplektum, Reconcavona? incerta; Petrobrasia signum; Clinocypris? weilleri; Salvadoriella redunca posterior e Cypridea sp. Considering species occurring at Gameleira beach, the first listed species named the Zone Paracypridea brasiliensis, coded as O04, a last occurrence interval zone, is the uppermost of the three biostratigraphic unities of Rio da Serra Local Stage. From the base upward of this stage, the other two biostratigraphic unities are: Zone Theriosynoecum varietuberatum, coded as O02, and Zone Cypridea (Morininoides) candeiensis, coded as O03. Each of zones O02 and O03 are divided into two subzones and, the uppermost O04 into five subzones based on last occurrence interval. So, the Rio da Serra Local Stage is composed of three zones and nine subzones attributed to Berriasian to Valanginian interval. Based on these nine subzones, it is possible to divide into lower, subzones O02.1, O02.2 and O03.1, mid, subzones O03.2, O04.1 and O04.2, and upper, subzones O04.3, O04.4 and O04.5, Rio da Serra Stage. Considering this and the listed occurrences of ostracodes species, it is possible attribute both outcrops to mid Rio da Serra Stage, inferred to be Valanginian. As perspective for the future on biostratigraphy, it is conducted integrated studies with paleomagnetism approaches and correlation with occurrences on western Africa.

The Late Cretaceous was a crucial period in Earth's history, characterized by a greenhouse climate, several major geological events and, in particular, the Angiosperm Terrestrial Revolution. This revolution notably reshaped terrestrial diversity and ecosystems, with the spread of angiosperms altering plant communities and aquatic ecosystems by modifying habitats and food sources. Non-marine ostracods, being sensitive to environmental shifts, provide valuable insights into these changes. However, the lack of high-resolution richness curves for non-marine ostracods has limited our understanding of the patterns and processes of evolution of terrestrial life during this period.

In this study, 76 Cretaceous non-marine sections and drill cores containing ostracod fossils from China were compiled and subjected to rigorous data-quality control. Fourteen age-control stratigraphic points/levels, such as zircon U-Pb dating, magnetic stratigraphy, and astronomical tuning were used to place precise chronological constraints on the resulting richness estimates. The Constrained Optimization (CONOP) method was used to construct a high-resolution non-marine ostracod richness curve with an estimated temporal resolution of approximately 0.079 million years. This curve shows an overall increasing trend throughout the Late Cretaceous, with several prominent richness declines in the late Coniacian, the Santonian-Campanian boundary, and the late Campanian.

These richness fluctuations are closely correlated with contemporaneous environmental changes, particularly in precipitation and climate. The expansion of aquatic angiosperms during the Angiosperm Terrestrial Revolution provided habitats for ostracods and indirectly enhanced their food sources, including epiphytic microorganisms, algae and organic sediments. Our results also provide a framework for global comparisons of richness trends over the study interval.

The Jehol Biota is a world-renowned early Cretaceous terrestrial ecosystem in East Asia, with exceptionally well preserved fossils, providing important insights into the origin and evolution of birds and feathers, as well as the early diversity of mammals and angiosperms.Here we report a new lagerstätte fossils from the Hesonggou section in Lingyuan area, western Liaoning.The Hesonggou section (Yixian Formation) is well exposed and mainly composed of mudstone, shale and sandstone, interbed with tuff. The top and bottom of the section are mainly composed of red sandstone and mudstone, while the middle part is mudstone with abudant fossils, which belong to the Jehol biota. Relatively abundant fossils are identified, such as Lycoptera davidi, Palaeocambarus licenti, Arguniella lingyuanensis, Eosestheria lingyuanensis, Schizolepis sp., Czekanowskia sp., Liaoningcladus boii, etc. Based on comprehensive geochronological and biostratigraphic correlation, theHesonggou section is is confidently assigned to the the Yixian Formation (Barremian). The biota in this area exhibits relatively high abundance and taxonomic diversity, suggesting a thriving ecosystem. Paleoenvironmental reconstructions indicate that these organisms inhabited a small lacustrine system under a warm, sub-humid climatic regime..

Keywords: Jehol Biota, Lingyuan basin, Yixian Formation

The Marília Formation records the distributive fluvial system (DFS) stage of the Bauru Basin (Southeastern Brazil) during the Maastrichtian, dominated by braided river deposits. Based on the relationship between facies and paleosols, this work proposes an environmental evolution and estimates the rates of sedimentation and pedogenesis in the Late Cretaceous of Southeast Brazil. By studying bi-dimensional sections, we identified facies associations that comprise four main architectural elements: channels (CH), laminated sand sheets (LS), sand bars (SB), and overbank deposits (OF). The sedimentary dynamics were characterised by the formation and abandonment of channel complexes related to aggradation, the generation of carbonate palaeosols, clay illuviation, and vegetation growth within the channels. Fifteen palaeosol profiles occur intercalated in the deposits. They are characterised by horizons Bt, Btk, Bss, C, and Ck, which allows a possible general comparison with the present soil orders: Alfisols, Aridisols, Entisols, and Vertisols. The macro- and micromorphological characteristics, combined with the mineralogy of these horizons, indicate arid and semiarid climatic conditions, with the minimum time of profile formation varying from 3740 to 5000 years. The genetic relationship between architectural elements, palaeosols, and the piling pattern suggests that the Marília Formation resulted from a succession of high-frequency depositional events of 10³ to 10⁴ years. This approach may allow an understanding of the avulsion and pedogenesis processes in the distal distributive fluvial systems. Thanks to FAPESP for supporting the Project 2020/07997-4, "Exploring the diversity of South American Cretaceous dinosaurs and associated fauna." Thanks to CNPq for the grants ( 310734/2020-7 and 303977/2021-3).

The lake transgression event (LTE) associated with a lake anoxic event (LAE) has been reported previously from the Cretaceous Nenjiang Formation in the Songliao Basin, NE China. Detailed studies based on sedimentology, dinoflagellates, ostracods, and biomarkers have provided important evidence for this LTE in Member 1 of the Nenjiang Formation (K2n1). However, the related floristic record has not received enough attention. In this paper, palynological data of borehole Ji Tao Di-1 (JTD-1) from the western slope of the Songliao Basin were analyzed to investigate vegetation and climate changes associated with this Cretaceous LTE. Three palynological sub-assemblages reflect significant paleovegetation and paleoclimate changes through this LTE and reveal ecosystem fluctuations related to the global Cretaceous oceanic anoxic event (OAE3). A significant increase in the relative abundance of Schizaeoisporites and Cyathidites spores may represent the LTE in the Nenjiang Formation. Principal Components Analysis (PCA) and Sporomorph EcoGroup (SEG) model indicate that climate changed from cool and humid subtropical before the LTE, to relatively warm temperate during the LTE and temperate after the LTE in this area. The relatively warmer and drier climate during the later period of the LTE may be influenced by the contemporaneous OAE3. After the LTE, the highland mixed forests were dominant, and a large number of angiosperms (i.e., members of the Proteaceae) occupied the ecological niches of the middle canopy, indicating that the flourishing of angiosperms in the late Santonian may be closely related to environmental disturbances resulted from the LTE and OAE.