Daran Zheng

The zygopteran family Burmacoenagrionidae Zheng, Nel & Wang, 2019 is endemic to the west Burma Block and occurring during the mid-Cretaceous (Zheng et al., 2019). It was considered to be a member of the Coenagrionoidea Kirby, 1890, which is the dominant group of the extant damselflies (Dijkstra et al., 2014). Four burmacoenagrionid genera have been previously described, including Burmacoenagrion Zheng, Nel & Wang, 2019, Burmagrion Möstel, Schorr & Bechly, 2017, Burmachistigma Zheng, Nel & Wang, 2019, and Electrocoenagrion Zheng, Nel & Wang, 2019 (Möstel et al., 2017; Zheng et al., 2019). This indicates that Burmacoenagrionidae is the most diversified zygopteran family currently recorded in the Kachin amber (Zheng, 2020).

The Carnian Pluvial Episode (CPE; 234–232 million years ago) is an iconic but poorly understood hyperthermal event. Here, we present an integrated high-resolution (~2–10 kyr) multi-proxy record from a Carnian lacustrine succession of the Junggar Basin of northwestern China. We find that the rapid CPE onset (~15.8 kyr) could have been the result of volcanism and subsequent surface carbon-cycle feedbacks. The CPE terrestrial carbon cycling, at a scale of ± 1‰ (δ¹³C_org), displays an in-phase relationship with the 405-kyr-long-eccentricity parameter, paralleling the warmhouse climate–carbon-cycle interactions throughout the Oligo–Miocene. The CPE hydrological cycle was typified by increased aridification in continental interiors and multiple precipitation centres at low-latitude eastern regions of Pangea and at the poles. The carbon and hydrological cycle changes of the CPE include features reminiscent of other warm events, suggesting they may share key characteristics and hold important clues to Earth system functioning.

The fifth burmaeshnid dragonfly, Neoaeschna kachinensis gen. et sp. nov., is described based on the basal parts of a pair of fore- and hindwings from Kachin amber, indicating that Burmaeshnidae Huang, Cai, Nel & Bechly, 2017 is the most diverse family of true dragonflies in Kachin amber. The new dragonfly differs from the other genera in having one row of cells present in the postdiscoidal area basal of the midfork, the trigonal planate being obsolete, and one or two crossveins present basal of the CuP-crossing in the submedian space.

A new hemeroscopid dragonfly, Parahemeroscopus jiuquanensis gen. et sp. nov., is described from the Lower Cretaceous Zhonggou Formation of the Jiuquan Basin, northwestern China. Parahemeroscopus gen. nov. has the mixed characters of the hemeroscopid genera Hemeroscopus Pritykina, 1977 and Abrohemeroscopus Ren, Liu & Cheng, 2003, and probably represents a transitional dragonfly from Abrohemeroscopus to Hemeroscopus. The new finding not only adds to the diversity of the Hemeroscopidae Pritykina, 1977, but also provides clues for revealing the early evolution of the hemeroscopid dragonflies.

The mesuropetalid dragonfly Sinomesuropetala daohugensis Boudet, Nel & Huang, 2023, is here revised based on a new well-preserved dragonfly from the Haifanggou Formation of Inner Mongolia, northeastern China. The new specimen allows us to complete the forewing characters of this species, showing the close relationship of Sinomesuropetala Boudet, Nel & Huang, 2023 with Mesuropetala Handlirsch, 1906. The mesuropetalid dragonflies are currently recorded from the Late Jurassic and Lower Cretaceous deposits of east Asia, East Central South Europe, and southern America, indicating the wide distribution and the possible long-distance migration ability of some basal aeshnopteran dragonflies during these epochs.

Amber is a fossilized tree resin that ranges in age from the Carboniferous to the Cenozoic. It occurs globally from the Arctic to Antarctica. As the resin petrifies and turns into amber, it can enclose and preserve other materials. Amber with inclusions can help reconstruct past biodiversity and ecosystems. Some amber contains fossils representing the oldest and most detailed records of critical evolutionary traits or markers. Inclusions can even capture behavioral indicators previously only observed in extant organisms. Evidence of insect pollination of flowering plants and dragonfly mating behavior appears in amber, as does the morphological specialization of insects, indicating sociality and social parasitism. Dating amber deposits can help calibrate evolutionary events and inform reconstructions of past ecosystems. While the direct dating of amber remains impossible, age constraints on most amber deposits are based on correlations or relative dating, methods that come with significant uncertainties. This study discusses two cases using ⁴⁰Ar/³⁹Ar and U–Pb geochronologic methods to constrain the ages of amber deposits in China and the paleo-ecosystems they record. This paper also summarizes how radio-isotopic dating and other techniques combined with the analysis of inclusions in amber can help elucidate biogeography and the dynamic relationship between life and the physical environment.

Trouvez l'article de fascicule A new campterophlebiid damsel-dragonfly (Odonata: Isophlebioidea) from the Middle Jurassic Yanan Formation of Yulin City, Shaanxi Province, NW China sur le site des Publications scientifiques du Muséum national d'Histoire naturelle, Paris

Over the past decades, abundant and well-preserved vertebrate fossils, known as the Urho Pterosaur Fauna, have been recovered from the Lower Cretaceous Tugulu Group in Junggar Basin, Xinjiang, NW China. Excavated materials belong to pterosaur, plesiosaur, dinosaur, crocodylomorph, and turtle taxa. As such, they provide key insights into the evolutionary history of several critical vertebrate groups in the Early Cretaceous. The Junggar assemblages have been interpreted as belonging to the Jehol Biota sensu lato, representing its northwesternmost known geographic extent. This research presents a new chemical abrasion−isotope dilution−thermal ionization mass spectrometry U-Pb age of 135.2 ± 0.9 Ma (2σ internal error) from a tuffaceous bed stratigraphically below the fauna-bearing layers, indicating a Valanginian maximum age for the Urho fauna. Combined with available biostratigraphic data, the results bear several important paleobiologic implications for the Early Cretaceous vertebrates. First, the Dsungaripterus pterosaur and Psittacosaurus ornithischian fauna appear to have emerged earlier than previously believed. Second, the data suggest that the oldest carcharodontosaurids in Asia appeared during the Valanginian Stage and extend the age range of basal coelurosaurs and basal crocodyliforms. Our results do not support the notion of the Jehol Biota sensu lato migrating as far west as the Junggar Basin in their later stages. The new information calls into question the temporal and spatial bases for the conventional, three-stage evolutionary theory of the Jehol Biota.