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.

Kekveus brevisulcatus sp. nov., a new featherwing beetle from mid-Cretaceous amber of northern Myanmar (Coleoptera: Ptiliidae).

Ptiliidae (featherwing beetles) is a group of minute staphylinoid beetles with a scarce fossil record. Here a second member of the Mesozoic genus Kekveus Yamamoto et al. is reported from mid-Cretaceous Burmese amber, with detailed morphology obtained through confocal microscopy. Kekveus brevisulcatus Li, Yamamoto, Newton & Cai sp. nov. shares with K. jason Yamamoto et al. the unpaired medial pronotal fovea and narrowly separated transverse metacoxae, but can be separated from the latter based on its less elongate body, shorter pronotal foveae, and much weaker transverse depression on the head. Our phylogenetic analyses support the discheramocephalin affinity of Kekveus, although its relationship with other members of Discheramocephalini cannot be confidently resolved.

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.

Revisiting the Raractocetus Fossils from Mesozoic and Cenozoic Amber Deposits (Coleoptera: Lymexylidae).

The fossils once assigned to Raractocetus Kurosawa from the Mesozoic and Cenozoic amber deposits differ from extant Raractocetus in the longer elytra, the more strongly projecting metacoxae, and the hind wing with vein 2A forked. Thus, these fossils should be removed from Raractocetus. Cretoquadratus engeli Chen from Kachin amber appears to be conspecific with R. fossilis Yamamoto. As a result, R. fossilis and R. extinctus Yamamoto from Kachin amber, R. balticus Yamamoto from Baltic amber, and R. sverlilo Nazarenko, Perkovsky & Yamamoto from Rovno amber are transferred to Cretoquadratus Chen, as C. fossilis (Yamamoto) comb. nov., C. extinctus (Yamamoto) comb. nov., C. balticus (Yamamoto) comb. nov., and C. sverlilo (Nazarenko, Perkovsky & Yamamoto) comb. nov., and C. engeli syn. nov. is suggested to be a junior synonym of C. fossilis.

New species of Vetuprostomis from mid-Cretaceous amber of northern Myanmar (Coleoptera: Tenebrionoidea: Prostomidae).

Two new species of the prostomid genus Vetuprostomis Engel Grimaldi (Coleoptera: Tenebrionoidea: Prostomidae), V. angularis Li Cai sp. nov. and V. gaoi Li Cai sp. nov., are described from the mid-Cretaceous Burmese amber. Vetuprostomis is suggested to be more closely related to extant Dryocora Pascoe distributed in Australia and New Zealand, rather than the widespread genus Prostomis Latreille. A key to prostomid genera, as well as species in genus Vetuprostomis, is provided.

A new marsh beetle from mid-Cretaceous amber of northern Myanmar (Coleoptera: Scirtidae).

As one of the earliest-diverging lineage of the megadiverse beetle suborder Polyphaga, marsh beetles (Scirtidae) are crucial for reconstructing the ancestor of all polyphagan beetles and the ecomorphological underpinnings of their remarkable evolutionary success. The phylogeny of marsh beetles has nonetheless remained challenging to infer, not least because of their fragmentary Mesozoic fossil record. Here we describe a new scirtid beetle genus and species, Varcalium lawrencei gen. et sp. nov., preserving internal tissue, from Albian-Cenomanian Kachin amber (ca 99 Ma), representing the second member of this family known from the deposit. Based on a formal morphological phylogenetic analysis, Varcalium is recovered within the crown-group of Scirtinae, forming a clade with other genera that possess subocular carinae. The finding suggests that the crown-group of Scirtinae has already diversified by the mid-Cretaceous.

The Earliest Corotocini (Insecta: Coleoptera: Staphylinidae) from Dominican Amber, with Remarks on Post-Imaginal Growth Influence on Termitophile Taxonomy.

Pareburniola dominicana Zilberman, Yin & Cai gen. et. sp. nov. is the very first fossil record of the tribe Corotocini, reported from Miocene Dominican Republic amber. The new species, which is based on a stenogastric individual, is described and illustrated and is included in the subtribe Corotocina due to the combination of a tarsal formula 4-4-4, an elongated gula, a developed labial palp, a reduced fourth palpomere, separated metacoxae and a glandular structure on the posterior region of the head. Since the taxon belongs to the physogastric tribe Corotocini, which presents post-imaginal growth, this phenomenon is herein discussed, and its current knowledge is used to understand the possible outcomes during morphological changes in the fossil species.

Nothotytthonyx, a new genus of Malthininae (Coleoptera, Cantharidae) from mid-Cretaceous amber of northern Myanmar.

A new fossil genus and species of Cantharidae, Nothotytthonyxserratus Li, Biffi, Kundrata & Cai gen. et sp. nov., is reported from mid-Cretaceous Burmese amber. The new species is tentatively attributed to the extant subfamily Malthininae based on a combination of characters, including the symmetrical apical maxillary palpomeres, shortened elytra, pronotum with arched margins and well-defined borders, tibiae with apical spurs, and tarsal claws simple, although its well-developed gonostyli are atypical in Malthininae. The discovery of Nothotytthonyx also suggests a possible Gondwanan origin for Malthininae.

Prolucanus beipiaoensis gen. et sp. nov.: The First Fossil Species of Lucaninae (Coleoptera: Lucanidae) from the Early Cretaceous of Northeastern China.

A new stag beetle fossil is described from the Yixian Formation in northeastern China. A new genus is established based on this well-preserved specimen. Prolucanus beipiaoensis gen. et sp. nov. is firmly placed in the extant lucanid subfamily Lucaninae based on its broad prosternal process and geniculate antennae. Our discovery represents the first fossil record of Lucaninae from the Late Mesozoic of China and the oldest reliable record belonging to the subfamily. We also summarize the fossil species of stag beetles found in China and the described fossil species of the subfamily Lucaninae found in the world. A key to all fossil genera of Lucanidae from China is provided.

A New Species of Vetubrachypsectra from Mid-Cretaceous Amber of Northern Myanmar (Coleoptera: Brachypsectridae).

A new species, Vetubrachypsectra huchengi Li, Kundrata & Cai sp. nov., is described from mid-Cretaceous Burmese amber on the basis of a single adult female. The species is assigned to genus Vetubrachypsectra Qu & Cai based on its serrate antennae, long maxillary palps, presence of tibial spurs, and elytra without clear striae. Vetubrachypsectra huchengi differs distinctly from V. burmitica Qu & Cai, the only other species in the genus, in having the pedicel apically attached to the scape. Some other differences between the female of V. huchengi and the male of V. burmitica include less serrate antennae, a broader pronotal disc, a broader scutellar shield and smaller tibial spurs. However, at least some of these characters can be considered sexually dimorphic.

Fire-prone Rhamnaceae with South African affinities in Cretaceous Myanmar amber.

The rapid Cretaceous diversification of flowering plants remains Darwin's 'abominable mystery' despite numerous fossil flowers discovered in recent years. Wildfires were frequent in the Cretaceous and many such early flower fossils are represented by charcoalified fragments, lacking complete delicate structures and surface textures, making their similarity to living forms difficult to discern. Furthermore, scarcity of information about the ecology of early angiosperms makes it difficult to test hypotheses about the drivers of their diversification, including the role of fire in shaping flowering plant evolution. We report the discovery of two exquisitely preserved fossil flower species, one identical to the inflorescences of the extant crown-eudicot genus Phylica and the other recovered as a sister group to Phylica, both preserved as inclusions together with burned plant remains in Cretaceous amber from northern Myanmar (~99 million years ago). These specialized flower species, named Phylica piloburmensis sp. nov. and Eophylica priscastellata gen. et sp. nov., exhibit traits identical to those of modern taxa in fire-prone ecosystems such as the fynbos of South Africa, and provide evidence of fire adaptation in angiosperms.

An unusual elateroid lineage from mid-Cretaceous Burmese amber (Coleoptera: Elateroidea).

We here report a new elateroid, Anoeuma lawrencei Li, Kundrata and Cai gen. et sp. nov., from mid-Cretaceous Burmese amber. Though superficially similar to some soft-bodied archostematans, Anoeuma could be firmly placed in the polyphagan superfamily Elateroidea based on the hind wing venation. Detailed morphological comparisons between extant elateroids and the Cretaceous fossils suggest that the unique character combination does not fit with confidence into any existing soft-bodied elateroid group, although some characters indicate possible relationships between Anoeuma and Omalisinae. Our discovery of this new lineage further demonstrates the past diversity and morphological disparity of soft-bodied elateroids.