Current Research in Insect Science

FABRIKANT D., HUANG D., FU Y.

The extinct planthopper family Mimarachnidae is well represented in mid-Cretaceous Kachin amber of northern Myanmar. In this study, three new species of mimarachnid planthoppers are described and illustrated from Kachin amber, all belonging to the genus Multistria Zhang, Yao & Pang, 2021. The new species, Multistria irregularis sp. nov., M. juanae sp. nov., and M. fionae sp. nov., are primarily distinguished from each other mostly by tegminal characters, such as the branching pattern of the secondary veinlet meshwork, venation, and the colour patterns, as well as differences in head. The tegminal diagnostic characters of Multistria are briefly examined.

LE CADRE J., MELZER R.R., MÜLLER P., HAUG C., HAUG J.T.

Chilopoda, part of Myriapoda, is a species-rich group of ~3300 formally described species. Yet, the phylogenetic relationship of centipedes is not fully clear, and the scarceness of their fossil record, compared to the closely related Diplopoda, is a major challenge for understanding their evolutionary history. Within Chilopoda, Lithobiomorpha is one of the most problematic concerning its fossil record, so far restricted to the Cenozoic (~40 mya) and with a single lithobiomorphan-like specimen from Kachin amber (~100 mya). Here, we report three new exceptionally well-preserved lithobiomorphan specimens from Myanmar amber (~100 mya). These represent the first report of oldest representatives of Henicopidae from the Cretaceous, and with this the oldest definite record of Lithobiomorpha. Two specimens have ten pairs of walking legs (stage IV), and one has a fully developed trunk. These specimens are similar in many aspects to the extant group of Henicopidae and, more precisely, to Lamyctes Meinert, 1868. The specimens seemingly lack ocelli, exhibit ~14 (stage IV) and 24 antenna articles, have 2+2 coxosternite teeth, and present tooth-like setae on their coxosternite margins (=porodont). The fully developed specimen possesses a tibial spinose projection on each tibia of legs 1–11, a blunt projection on the tibia of leg 12, and undivided tarsi on their legs 1–12. With the finding of these specimens, we expand the fossil record of Lithobiomorpha significantly.

ZHANG Y., HUANG D.

Rotularia Defrance is a common extinct genus of planispirally coiled fossil polychaete worms in the family Serpulidae from shallow marine environment. Here, we describe a large collection of Rotularia specimens attached to mid-Cretaceous Burmese amber. The fossil record of Rotularia serves as a valuable tool for calibrating polychaete evolution and suggests that the Burmese amber forest was likely situated not far from the seashore.

MCMENAMIN M.A., FLEURY D.

A fossil chimaeroid tooth plate (Ischyodus sp.) from the Cretaceous of Frankstown, Mississippi shows exceptional preservation of tritor microstructure. Diagenetic loss of the petrodentine/whitlockin in this specimen has revealed the ultrastructure of the vascular tubule networks of tritor interior structure. The observation that vascular tubes running through the hard tissues of chimaeroid tritors host odontoblast cells supports the hypothesis of an odontoblastic origin for chimaeroid tritor tissue.

YUN C.

Acheroraptor temertyorum is a dromaeosaurid theropod, probably a saurornitholestine, found in the upper Maastrichtian Hell Creek Formation of Montana. This enigmatic dromaeosaurid is known from only a partial maxilla and dentary, as well as referred isolated teeth, making even the general aspects of its palaeobiology largely elusive. In this work, beam theory is applied to the lower jaw of Acheroraptor temertyorum to document the biomechanical properties of the mandible of this taxon and to infer the feeding mechanism of this dinosaur. This work suggests the lower jaw of Acheroraptor temertyorum is mainly adapted to produce rapid, slashing bites, as previously inferred for other dromaeosaurids. Intriguingly, despite having a closer phylogenetic affinity with Saurornitholestes langstoni, overall biomechanical properties of the lower jaw of Acheroraptor temertyorum are found to be weaker than the former taxon, but rather comparable to Asian velociraptorines. Such results may indicate Acheroraptor temertyorum preyed on smaller animals compared to other saurornitholestines, and suggest diets or predation methods of saurornitholestine dromaeosaurids might have been more diverse than previously assumed.

GOU X., FENG Z.

A list of all known fossil wood taxa recorded from the Cretaceous, up to December of 2024, is given. The list contains 57 genera and 317 species of gymnospermous wood described from 48 countries across seven continents. 39 genera and 165 species were reported from Asia, 28 genera and 67 species from Europe, 33 genera and 48 species from Africa, 20 genera and 48 species from North America, 13 genera and 35 species from South America, 4 genera and 4 species from Australia and 5 genera and 12 species from Antarctica. 54 genera and 171 species were documented from the Lower Cretaceous, and 26 genera and 76 species from the Upper Cretaceous. Systematically, 1 genus and 2 species belong to Cycadales, 1 monotypic genus belongs to Bennettitales, 2 genera and 3 species belong to Ginkgoales, 52 genera and 306 species are of Coniferales, and 1 genus and 3 species are incertae sedis.

KARL H., SAFI A., TICHY G.

Resolving the phylogeny of fossil turtles is uniquely challenging given the high potential for the unification of convergent lineages due to systematic homoplasy. Equivocal reconstructions of turtle evolution and biogeographic or palaeo-climatic data with phylogenetic hypotheses and new images of the holotype reconstructions of fossil turtles are important for prehistoric turtle fossil remains. Here we describe the cranial anatomy and holotype reconstruction of the Late Cretaceous turtle, Australobaena chilensis from the Quiriquina Formation of the Maastricht Ocean Horizon Chile, which was identified as a new genus and species of Baenidae (an extinct family of para-cryptodiran turtles) in 2002 by Karl and Tichy. The holotype is “SMF R 415”, a partially destroyed skull without a lower jaw, and with a unique cranial plane. This taxon belongs to Baenidae, an extinct freshwater family from the Cretaceous period in North America. This is the first baenid fossil found outside of North America, and we re-describe and reconstruct it with new photographs and illustrations of the cranial anatomy of this material (Holotype).

PONTING J.

Schrammen (1910) described a genus of fossil tetillid sponge, naming it Tetillopsis Schrammen, 1910, and described two species from north-western Germany, viz., T. doeringi Schrammen and T. longitridens Schrammen. Tetillopsis doeringi was later designated as the type species of the genus (de Laubenfels, 1955); and this name is still used in current taxonomic practice (https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=2987 The Paleobiology Database 2024).

LIU Q., JI X.

The depositional architecture between unconfined and confined turbidite sheet systems are increasingly recognized, but the major differences are not summarized. This paper aims to summarize the major differences based on the well-studied published systems with known degree of confinement and depositional architectures. The unconfined and confined turbidite sheet systems differ greatly in four aspects: sedimentary facies, stacking patterns of individual beds, facies associations and onlap styles. The sedimentary facies in confined systems are mainly thick beds, occasionally with grain size breaks, overlain by thick mud caps; whereas beds in unconfined turbidite systems present less mud proportion. The stacking patterns in confined systems in mainly vertically stacked, whereas compensationally stacked in strike direction, and progradationally or retrogradationally stacked in dip direction. One facies association have only been identified in confined systems and four facies associations are found in unconfined systems. The vertical log of unconfined turbidite sheet systems presenting a transition of facies association, whereas no transitions in confined systems. The depositional architecture of turbidite sheet systems is controlled by both sediment supply and basin relief. The establishment between degree of confinement and various parameters in this study can be applied in the petroleum industry.

HU X., JIANG J., CAI Y., HAN Z., XU Y.

Anthropocene global warming is largely associated with fossil fuel carbon emissions. Temporal scaling provides a way to place current carbon emissions on a geological scale. The scaling of carbon emissions at the onset of hyperthermal events suggests that we might anticipate higher carbon emission rates over longer time scales than what we currently observe in the Anthropocene. However, this inference is uncertain due to limited data concerning the accumulations and time intervals of carbon emissions of Meso-Cenozoic hyperthermal events. While on the long-time hyperthermal-event scales of several to hundreds of kiloyears, modern carbon accumulations and emission rates are 9 times greater than those of the hyperthermal-event emissions. The present-day carbon release can be effectively compared to the onset of hyperthermal events through temporal scaling. If current carbon emission trends persist, we may reach the carbon emission thresholds for hyperthermal events in one to three hundred years, getting an intensified hydrological cycle, enhanced continental weathering and ocean acidification. And if the situation gets worse, we may reach the upper limit of the carbon emission threshold for hyperthermal events (e.g., Permian-Triassic Boundary event, PTB) with a biotic mass extinction over four to thirteen hundred years. This study offers new insights into current carbon emissions from a temporal scale perspective, enhancing our understanding of contemporary climate change.

FANG G., WU F.

The Pycnodontiformes is a distinctive group of fossil actinopterygian (ray-finned) fishes from the Late Triassic to Palaeogene. Tibetodus gyrodoides, reported in 1954, represents the only known fossil record of this group in China, holding significant scientific and historical importance. In this study, non-destructive techniques such as scanning electron microscopy (SEM) and micro-computed tomography (micro-CT) were utilised to reexamine the specimen, providing new insights into both the surface morphology and internal structures of the vomer and its teeth and investigating the process of tooth wear. A tooth covered by matrix was also discovered. Furthermore, an Elliptical Fourier Analysis (EFA) was conducted to quantitatively analyse the morphology of the palatal teeth in this specimen, adding new data for future research on pycnodontiforms and their feeding behavior.

ZHANG S., ZHAO Y., CHEN Y., ZHANG B., XU Y., MA H., XIA Y., CAO J., YU Y., HAN L.

The Mesozoic–Cenozoic clastic rocks in the Tabei Uplift form one of the most hydrocarbon-rich zones in the Tarim Basin of China. Understanding how diagenesis has affected the petrophysical properties of the sandstone is crucial for developing regional exploration strategies. Although most studies have investigated the physical conditions during sedimentation and chemical processes during diagenesis, the hydrochemical environment during sedimentation and subsequent diagenesis has received little attention. This study employed petrographic observations, paleo-geothermal reconstructions, and paleoenvironmental analysis to constrain the regional climatic conditions, hydrochemical environment of deposition, and diagenetic features of clastic rocks in the Tabei Uplift. The sandstone at depths of 3500–6000 m is located mainly in the A phase of the middle diagenetic stage, and exhibits three types of diagenesis. Triassic–Jurassic sandstones are dominated by silica, kaolinite, and chlorite cements, Cretaceous sandstones by mainly carbonate cements, and Paleogene sandstones by carbonate and evaporite cements. These diagenetic stages correspond to paleoclimatic changes during the earliest Late Jurassic and the maximum marine transgressions of the Proto-Tethys during the Paleogene, thereby highlighting the influence of climatic change and transgressions on the water conditions during deposition and the type of diagenesis.

XU Y., LAI W., HU X.

The mid-Cretaceous Langshan Formation is a massive limestone unit, outcropping typically in the northern Lhasa block. A Xiongba section, measured near the type section of the Langshan Formation, is here described. The succession consists of orbitolinids limestone, where eight microfacies have been recognized. The lower part of the Langshan Formation consists of discoidal orbitolinids with other heterotrophic associations, including echinoderms, sponge spicules, and bivalves. In contrast, the upper part of the Langshan Formation features conical orbitolinids with an abundance of green algae and small benthic foraminifers. We interpret the morphological changes in orbitolinids as being influenced by bathymetry. Consequently, the microfacies variations in the Langshan Formation in the Xiongba section represent a shallowing upward sequence.

JIANG J., HU X., GARZANTI E., BOUDAGHER-FADEL M., AN W.

The Xigaze forearc basin is a key region to understand the evolution of active continental margins related to Neo-Tethyan oceanic subduction. Most studies have focused on the sedimentary evolution during filling of the marine basin, but we here provide a detailed sedimentological and biostratigraphic analysis of the last, uppermost Cretaceous to Paleogene phases of forearc sedimentation documented by the shallow marine to deltaic to fluvial Qubeiya, Quxia, and Jialazi formations exposed in the Cuojiangding area. By comparing these sequences with regional tectonic and global climate events and sea-level curves, a reconstruction of the environmental evolution during this final filling stage is proposed, placing emphasis on the eustatic control of carbonate deposition in the Qubeiya and Jialazi formations. These transgressive intervals are separated by two regressive episodes unrelated to global sea-level trends that led to the demise of the carbonate platform. The first episode, documented by fan-delta deposits of the Quxia Formation, occurred at the time of initial India-Asia collision. The second episode, documented in the central part of the Jialazi Formation, occurred during the Paleocene-Eocene Thermal Maximum, likely driven by an intensified hydrological cycle. These results provide new insight into the palaeo-tectonic and palaeo-environmental evolution during the closure of the Neotethys seaway between India and Asia.

HE Z., LI X., LI Y., CHENG J.

The presence of the Zhongba microterrane causes the Yarlung–Tsangpo suture zone to be bifurcated into two parts in its western segment: the Northern Ophiolitic Belt and Southern Ophiolitic Belt. This indicates that the evolution of the Neo-Tethys Ocean in the western segment is more complex than previous interpretation. Between the Southern Ophiolitic Belt and the Zhongba microterrane, there exists a successive stratigraphic sequence. In this study, a total of 15 genera belonging to 20 species of radiolarians were identified from the siliceous strata of the Dangxin Formation within this sequence, constraining the age of the Dangxin Formation to the Barremian, Early Cretaceous. Additionally, a stratigraphic column was constructed based on the basic understanding of this stratigraphic sequence from regional geological surveys, and it was compared with deep-water sediments in the Tethyan Himalaya. The results show that this sequence can be correlated with the Rilang, Duobeng, Chuangde, and Zongzhuo formations, which were deposited on the passive margin of the Indian plate.