Mesozoic

**Redescription of the Upper Jurassic Aeshna antiqua Vander Linden, 1827 in the Anisopteran family Protolindeniidae (Odonata)**

ANDRÉ NEL — 2025-03-28

The holotype of the Upper Jurassic species ‘Aeshna’ antiqua Vander Linden, 1827, from the lithographic limestone of Bavaria (Solnhofen Konservat-Lagerstätte), is redescribed. It turns out that it is conspecific with Protolindenia wittei (Giebel, 1860), the type species of the genus Protolindenia Deichmüller, 1886. We therefore transfer ‘Aeshna’ antiqua to the genus Protolindenia under the name Protolindenia antiqua (Vander Linden, 1827) comb. nov., and Protolindenia wittei is considered as a junior synonym of P. antiqua (Vander Linden, 1827).

A contribution to the taxonomy of Eucnemidae from mid-Cretaceous Kachin amber (Coleoptera: Elateroidea)

YAN-DA LI — 2025-03-28

Two new genera and species of false click beetles are described and illustrated from mid-Cretaceous Kachin amber. Yallmoleia arriagavarelai gen. et sp. nov. differs from similar species that have basally closed lateral antennal grooves on the hypomeron primarily by the absence of elytral striae and the morphology of antennae and legs. Xanrofeurya tomaszewskae gen. et sp. nov. is distinctive among Eucnemidae from Kachin amber in having basally open lateral antennal grooves on the hypomeron, and differs from extant species with this feature by its antennal morphology. Muonabuntor grandinotalis Li et al. and Jenibuntor pusillus Muona, previously described from Kachin amber, are transferred into Euryptychus LeConte as Euryptychus grandinotalis comb. nov. and Euryptychus pusillus comb. nov. Sieglindea antiqua Muona, which was claimed to originate from Kachin amber, is instead suggested to be from Eocene Baltic amber.

Mesofossils of an unrevealed affinity from the Jurassic of Siberia

NATALIA ZAVIALOVA — 2025-03-28

Enigmatic mesofossils were obtained via maceration of a microsporangium detached from a ginkgoalean pollen cone of Sorosaccus sibiricus Prynada from the Aalenian Ust’-Baley locality in Irkutsk Coal Basin, Siberia. The organic-walled remains were constituted by rounded oval bodies of sporopollenin-like colour, overlapped with their margins and arranged in several layers. The bodies had jointed continuous walls of variable thickness, which bifurcated, fused and formed inseparable structures. LM, SEM and TEM observations showed that the find cannot be in situ ginkgoalean pollen or other remains of a ginkgoalean plant. The further comparison also excluded the possibility that these mesofossils were alien pollen or spores, trapped in an open sporangium or fossilized in its close vicinity. Some slight ultrastructural similarities were only revealed to cryptospores, which led the search to algae and bryophytes. However, although fresh-water colonial algae and bryophytes theoretically could have been present in these lacustrine deposits, they differ from the mesofossils by smaller cells, which are grouped differently and show dissimilar outlines and wall ultrastructure. There is a possibility that the find represents wall fragments of some resting stage of an unknown organism. So far, no close analogues to these mesofossils have been found.

**Taxonomic additions to the genus †Megacoxa Brazidec et al., 2024 (Hymenoptera: Megalyridae) from Kachin amber**

CORENTIN JOUAULT — 2025-03-28

The extinct genus Megacoxa was recently described from Kachin amber and currently includes six formally recognized species. Despite the recent addition of three new species, additional, yet-undescribed specimens continue to be discovered in both institutional and private collections, awaiting formal description. The vast quantity of material extracted from the Kachin biota provides a practically inexhaustible source of new species. As with many insect families preserved in mid-Cretaceous Kachin amber, the diversity and number of megalyrid wasps remain significantly underestimated. In this study, I illustrate a new specimen of Megacoxa chandrahrasa Brazidec et al., 2024. I also describe a new species, Megacoxa miscea sp. nov., which exhibits a combination of characters found in M. janzeni and M. synchrotron. Furthermore, I present an updated identification key for Megacoxa species, incorporating this newly described species.

Geochronological study on the Sanjiaochengzi fossil locality: Age constraints on a Late Jurassic flora of western Liaoning, Northeast China

HAI-LONG GAO — 2025-03-28

Some fossil plants, previously identified as angiosperm species, have been reported from the “Jiulongshan”/Haifanggou Formation at the Sanjiaochengzi fossil locality in Huludao City, western Liaoning, Northeast China. However, the precise ages of these fossil plants remain uncertain. To address this issue, we conducted LA-ICP-MS zircon U-Pb dating on two tuffaceous interlayer samples from the fossil-bearing horizon of this section. The resulting ages of 159.9 ± 0.5 Ma and 160.1 ± 0.5 Ma constrain the depositional age of the fossil-bearing horizon to the Late Jurassic (Oxfordian stage). By integrating these chronological results with regional stratigraphic correlations, we determine that the fossil-bearing horizon of the Sanjiaochengzi section belongs to the lower part of the Tiaojishan Formation.

A new early Barremian fossiliferous amber outcrop from North Lebanon and its palaeoenvironment

DANY AZAR — 2025-03-28

A new fossiliferous amber outcrop in Akkar El-Atiqa (Akkar District, Northern Lebanon) discovered during recent geological prospection, is described. This discovery constitutes the 31^st amber outcrop with biological inclusions in Lebanon and hitherto the most septentrional one among those. It enriches and improves our knowledge about the palaeobiodiversity and the depositional palaeoenvironment of the North-Eastern coast of Gondwana during the early Barremian. An infrared spectrum of amber from Akkar El-Atiqa is given and discussed.

Distribution and mineralogical characteristics of amber in the Upper Cretaceous Gaogou Formation in Xixia, Henan Province, China

GAO-ZHE JI — 2025-03-28

The Xixia amber is the largest known Mesozoic amber deposit in China to date. Here we analyse amber collected over the years from 12 localities in the Upper Cretaceous Gaogou Formation in Xixia, Henan, including physical property tests and Fourier transform infrared spectroscopy (FT-IR) analysis. The main preservation forms of the Xixia amber include nest-like, vein-like, and layered irregular shapes, as well as gravel-like forms resulting from secondary transportation. Recent discoveries include numerous small-grained amber specimens preserved in grey-black silty shale rich in plant debris, suggesting a near-in-situ depositional environment. The Xixia Basin’s Late Cretaceous strata are renowned for their abundance in dinosaur eggs. In-depth research on the Xixia amber will help to understand the geological history and ecosystem evolution of the Xixia Basin during the Late Cretaceous, as well as the global distribution characteristics of Cretaceous amber.

Revising some fossil clam shrimps (Branchiopoda: Diplostraca: Spinicaudata) from the Upper Triassic in Yunnan Province and Chongqing City, southwestern China

SHAO-HUA FANG — 2025-03-28

Abundant Triassic spinicaudatans from China have been commonly assigned to the genus Euestheria Depéret & Mazeran. However, recent SEM-based studies have revealed that many of them do not belong to euestherids, as evidenced by their distinctive micro-ornamentations, revealed by scanning electron microscopy (SEM). In this study, we describe two spinicaudatan species, Polygrapta yipinglangensis comb. nov. and P. dazuensis comb. nov., which were previously identified as members of Euestheria from the Upper Triassic Ganhaizi and Xujiahe formations in south-western China. The carapace ornamentations of these species exhibit fine polygonal reticulations in the upper parts, which gradually transform to linear arrangements and radial lirae at the ventral regions. Based on these features, they are classified into Polygrapta Novojilov. Although the two species exhibit morphological similarities, they can be distinguished by variations in reticulation size and the width of linear arrangements in their marginal areas.

**Revision of Shurabia postiretis (Reculida: Geinitziidae) from the Jurassic of Yiyang Basin, Jiangxi, China**

HUI-XIN LAI — 2025-03-28

Meixiella postiretis Huang et al., 1991, was originally described as a new genus and species assigned to the distinctive family Geinitziidae (Reculida), based on a single forewing from the Lower Jurassic Menkoushan Formation (= Shuibei Formation in the present study) in the Yiyang Basin, Jiangxi Province, east China. Meixiella postiretis was subsequently transferred to Shurabia Martynov, 1937, a taxonomic assignment with which we concur. In the present study, we provide a detailed revision of the morphological characters of Shurabia postiretis. Based on its redefined diagnostic features and a holistic analysis of Jurassic insect-bearing strata in China, we discuss the evolutionary trajectory of Shurabia. Our findings provide support for its stratigraphic positioning from the late Early Jurassic to the early Middle Jurassic.

**A new large-sized flat bug from mid-Cretaceous Burmese amber: Cretozemira gregori sp. nov. (Hemiptera, Heteroptera, Aradidae)**

ERNST HEISS — 2025-03-28

Twelve genera and 20 species of Aradidae are reported and described to date from the mid-Cretaceous amber deposits of Kachin State (Northern Myanmar) (Ross, 2024).