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.

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.

Specialized adaptations for springtail predation in Mesozoic beetles.

Insects exhibit a variety of morphological specializations specific to particular behaviors, and these permit the reconstruction of palaeobiological traits. Despite the critical importance of predator-prey strategies in insect evolution, the appearance of particular aspects of predation are often difficult to determine from the fossil record of hexapods. Here we report the discovery of highly specialized, mid-Cretaceous ant-like stone beetles (Staphylinidae: Scydmaeninae) displaying morphological modifications unknown among living scydmaenids and associated with predation on springtails (Collembola), a widespread and abundant group of significantly greater geological age. Cascomastigus monstrabilis gen. et sp. nov. exhibits an extremely large body size, elongate clubbed maxillary palpi, toothed mandibles, and more importantly, slender and highly modified antennae that functioned as an antennal setal trap. Such an antennal modification is analogous to that of the modern ground beetle genus Loricera (Carabidae: Loricerinae), a group possessing a specialized antennal setal trap exclusively for the capture of springtails. The presence of an identical antennal setal trap in C. monstrabilis demonstrates a unique and dramatic form of obligate predation among the late Mesozoic insects.