Diplura is a cryptic and edaphic group of hexapod animals characterized by the presence of filiform or pincer-like cerci located at the end of the abdomen. As one of the early diverging lineages of Hexapoda, diplurans play a crucial role in unraveling the origin of the hyperdiverse insects. The fossil record of diplurans, however, is exceptionally limited due to their delicate bodies and habitat requirements. Here we report the discovery of a new japygid, Cretojapyx huangi gen. et sp. nov., entombed in mid-Cretaceous Kachin amber (northern Myanmar). This specimen exhibits distinctive features, including the well-developed carinae on abdominal segment X and cerci, left cercus lacking a prominent tooth and denticles, and right cercus with a postmedian tooth followed by uniseriate round denticles. Our finding provides a unique opportunity to gain valuable insights into the evolutionary history of this ancient lineage and deepen our understanding of terrestrial ecosystems during the Mesozoic.

The late Palaeozoic is the key period for understanding the origin and early evolution of insects, but Palaeozoic insects from China are poorly explored. Up to now, a total of 53 Carboniferous species, 27 Permian species and 1 Carboniferous–Permian species (12 orders or 2 superorders) have been described. Recently, with the development of biostratigraphy and isotope chronology, new insights into the stratigraphy of China and its timescale have been greatly improved. In this study, we discuss the ages of published Palaeozoic insects from China and summarize 23 Carboniferous species, 57 Permian species and 2 Carboniferous–Permian species.

The field trips will cover the Mesozoic stratigraphy and palaeontology of the Ordos Basin and the Loess Plateau (Fig. 1). The towering Qinling Mountains developed in the southern part of Xi’an. This investigation has entered the Loess Plateau from the Guanzhong Basin, where Xi’an is located, to the Tongchuan area, and the northernmost city of Yulin is a former desert area. The purpose of the investigation is to understand the Mesozoic strata, palaeontology, palaeoclimate and tectonic movements in the Ordos Basin. From the dry hot environment of the Red Bed in the mid-Triassic, it experienced a large cycle of warm and humid environment and then to the dry climate of the Early Cretaceous. Specifically, the middle and lower parts of the Middle Triassic Ermaying Formation are red beds, and coal seams begin to appear in the upper part of the formation; the overlying Middle-Upper Triassic Yanchang Formation has extensive oil and gas resources, and the lower strata are called by some authors the Tongchuan Formation and yielded a large number of insect fossils. At the turn of the Triassic and Jurassic, the area was elevated and lacked deposit. The Fuxian Formation of coal-bearing strata developed in the Early Jurassic. In the Lower-Middle Jurassic, the Yan’an Formation was a set of coal-bearing strata, which developed the largest coal mine in China. The Middle-Upper Jurassic Zhiluo Formation is a glutenite deposit. The unconformity between the Zhiluo Formation and the conglomerate at the bottom of the Lower Cretaceous Yijun Formation in this area indicates the Yanshan Movement Phase B. The Zhiluo Formation and the Yijun Formation is disconformity, and the Upper Jurassic-Lower Cretaceous Anding and Fengfanghe formations between the former two were missing. The Mesozoic fossil assemblages of the Ordos Basin are briefly introduced below, along with a composite column diagram (Fig. 2) depicting the Mesozoic strata of the Ordos Basin.

The evolutionary history of scorpions, one of the most charismatic groups of arthropods with over 2,500 described species, is a subject of great interest. Given their unique body plan and ancient fossil record, understanding their phylogeny is crucial. Recent genome-scale data have shown potential in elucidating interfamilial relationships within the scorpion tree of life; however, discrepancies between molecular datasets have also been observed. To address this, we explored the phylogenetic relationships of scorpions by synthesizing three previous phylogenomic studies using model comparison methods that account for among-site compositional heterogeneity. Our analyses indicate that under the infinite site-heterogeneous CAT and finite mixture models, the relationships within Scorpiones differ significantly from prevailing conclusions, particularly regarding the interfamilial relationships within Buthida. Our results show the following relationships: [Pseudochactoidea + [Buthoidea + Chaeriloidea]]. Our leave-one-out cross-validation analysis shows that the site-heterogeneous CAT-GTR+G model fits significantly better than the site-homogeneous model (LG) and finite mixture models (LG+C20, LG+C60), and it identifies contentious nodes in scorpion phylogeny. These analyses resolve a longstanding controversy in deep scorpion phylogeny and emphasize the significance of adequate modeling of compositional heterogeneity in reconstructing the deep phylogeny of scorpions.

Stoneflies (order Plecoptera), one of the earliest winged insects, are ecologically vital as freshwater bioindicators. Despite their ecological and evolutionary significance, a robust phylogeny for stoneflies has remained elusive. Here, we analyzed mitogenomes from 97 species representing all 17 families, employing site-heterogeneous models to reconstruct a comprehensive phylogeny of global Plecoptera. Our results provide several key insights: 1) Scopuridae is the earliest diverging lineage within Euholognatha; 2) Taeniopterygidae and Leuctridae form sister groups, representing the second diverging clade within Euholognatha; 3) Capniidae is resolved as the sister group to Nemouridae + Notonemouridae; and 4) the phylogenetic relationships within Systellognatha are resolved. Furthermore, by integrating palaeontological and chronostratigraphic data, we selected well-vetted fossil calibrations to reconstruct a temporal framework for Plecoptera evolution. Our study identifies key periods in Plecoptera’s early divergence and the origins of extant stonefly families, establishing a foundation for future research into their biogeography, morphology, and behavioral evolution.

Epermenia (Calotripis) sinjovi Gaedike, 1993, feeding on Angelica pubescens Maxim. and A. ursina Maxim., was previously recorded in Russia (Far East, Southern Siberia and Transbaikalia), Kunashir Island and Japan. This species is for the first time reported in China by rearing from a new host plant A. polymorpha Maxim. The larva and pupa are illustrated and described for the first time. Available biological information associated with the new host plant is also reported. Reference DNA barcodes are provided for E. (C.) sinjovi, which confirms that forewing distinct colors and morphological differences found in venation and genitalia among individuals are intraspecific variations. The adult morphological variations within population are analyzed and discussed.