Foveapeltis gen. nov., an unusual cleroid genus with large hypomeral cavities from mid-Cretaceous amber (Coleoptera: Cleroidea).

Beetles have a remote evolutionary history dating back to the Carboniferous, with Mesozoic fossils playing a pivotal role in elucidating the early evolution of extant families. Despite their exceptional preservation in amber, deciphering the systematic positions of Mesozoic trogossitid-like beetles remains challenging. Here, we describe and illustrate a new trogossitid-like lineage from mid-Cretaceous Kachin amber, Foveapeltis rutai Li, Kolibác, Liu & Cai, gen. et sp. nov. Foveapeltis stands out within the Cleroidea due to the presence of a significant large cavity on each hypomeron. While the exact phylogenetic placement of Foveapeltis remains uncertain, we offer a discussion on its potential affinity based on our constrained phylogenetic analyses.

A new fossil species of the extant genus Vicelva from mid-Cretaceous Kachin amber (Coleoptera: Staphylinidae).

A new species of the extant staphylinid genus Vicelva Moore & Legner, V. rasilis sp. nov., is reported from mid-Cretaceous Kachin amber of northern Myanmar. Vicelva rasilis is distinguishable from extant members of Vicelva by the smoother dorsal surface of head, pronotum and elytra, less prominent median projection of clypeus, unnotched mesal edge of mandibles, semiglabrous antennomere 6, and longer tarsomere 1. The pollen-containing coprolite attached to the beetle and the crystals within the beetle body provide valuable information about the biology and taphonomy of the fossil.

An enigmatic Cretaceous beetle with possible affinity to Erotylidae (Coleoptera: Cucujiformia).

The morphology of beetles of the recently defined superfamilies Erotyloidea, Nitiduloidea and Cucujoidea is varied. Determining the systematic positions of Mesozoic fossils within these groups can often be challenging. Here we describe and illustrate a puzzling cucujiform beetle, Isocryptophilus exilipunctus Li & Cai gen. & sp. nov., based on an individual from mid-Cretaceous Burmese amber. While we cannot definitively pinpoint the exact phylogenetic position of Isocryptophilus, its possible affinity to Erotylidae is discussed in light of our phylogenetic analyses. A broader-sampled morphological matrix, coupled with a robust molecular phylogeny of these groups, will be promising for clarifying the systematic placement of the fossil.

A new species of Polydesmidae (Myriapoda, Diplopoda, Polydesmida) from the mid-Cretaceous Burmese amber.

A new species of the flat-backed millipede family Polydesmidae, Propolydesmus cretaceus sp. nov., is described from the mid-Cretaceous Burmese amber. Detailed morphological characters are provided on the basis of 3 well-preserved adults (2 males and 1 females), 2 female subadults, and 14 additional specimens, using confocal laser scanning microscopy (CLSM) and X-ray micro-computed tomography (CT) with computer-aided 3D-reconstructions. The new species can be placed in the extant genus Propolydesmus. It majorly differs from other congeners due to the stronger gonopod acropodite and the presence of a bipartite gonopod exomerite.

A new species of Burmalestes Tomaszewska & lipiski from mid-Cretaceous Kachin amber (Coleoptera: Endomychidae).

The second species of the extinct genus Burmalestes Tomaszewska & lipiski, B. jingruoyaae Li & Cai sp. nov., is reported from mid-Cretaceous Kachin amber of northern Myanmar. The new species shares characters with both Burmalestes (antennomere 5 elongate and procoxae subcontiguous) and Cretaparamecus Tomaszewska et al. (protibiae toothed and pronotum without basolateral sulci), providing valuable information on the morphological variability of this group.

A new genus of japygids (Diplura: Japygidae) in mid-Cretaceous amber from northern Myanmar.

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.

New material of Cretaceoushormiops Loureno from mid-Cretaceous Burmese amber (Arachnida: Scorpiones: Protoischnuridae).

Among the scarce Mesozoic fossils, protoischnurid scorpions (Arachnida: Scorpiones: Protoischnuridae) represent a Cretaceous extinct group. In this study, we present the description of a new protoischnurid fossil, assigned to the genus Cretaceoushormiops Loureno, from mid-Cretaceous Burmese amber. Distinguished by a median suture and a comparatively short anterior margin in its carapace, the new specimen differs from all other species within Cretaceoushormiops. Our discovery sheds further light on the high diversity of mid-Cretaceous scorpions.

The first species of Thaumatomeropidae (Insecta: Mecoptera) from the Middle Triassic of China.

Thaumatomeropidae is an enigmatic mecopteran family previously known exclusively from the Triassic Madygen entomofauna of Kyrgyzstan. Thaumatomeropids display mosaic venation, closely resembling those of Meropeidae and Eomeropidae, yet distinguished by some more primitive characters. Here we describe and illustrate a new thaumatomeropid species, Thaumatomerope sinensis Lian & Huang, sp. nov., from the late Middle Triassic Tongchuan entomofauna of the Chang 7 Member of the Yanchang Formation near the Hejiafang Village, Tongchuan City, NW China. This new species is characterized by reduced Rs branches, and some unique forking patterns, including the single posterior last branch of Rs and multi-branched anterior first branch of M. It represents the first thaumatomeropid species reported outside Kyrgyzstan, indicating a broader geographical distribution of the family. Moreover, this discovery enhances the resemblance of mecopteran components between the Tongchuan and the Madygen entomofaunas.