New fossil evidence from southwestern China sheds light on the formation of modern distribution of Toddalia (Rutaceae)

Paleoanthropology could offer valuable insights into neurology by tracing the evolutionary origins of human motor and neural traits. Fossil evidence shows that bipedalism preceded brain expansion, revealing that upright locomotion and encephalization did not evolve in tandem. Early hominins retained ape-like brain organization despite walking upright, suggesting that neural complexity and prolonged childhood development emerged later. This sequence provides a framework for understanding persistent motor circuits in the human nervous system. Central pattern generators, deeply conserved networks producing rhythmic movements, exemplify ancestral continuities whose resilience explains the re-emergence of primitive motor patterns after cortical damage. Interpreting neurological signs through an evolutionary lens raises epistemological challenges, including the need for testable hypotheses and the avoidance of teleological bias. Yet clinically, reframing neurological signs, reflexes, and automatisms as evolutionary echoes could enrich diagnostic reasoning, inform prognosis, and inspire therapeutic strategies that harness ancestral circuits. In this sense, certain neurological signs may represent living traces of evolutionary history, bridging human ancestry with clinical practice.

Herein, we present a systematic investigation of plant fossils from the Yingzuilazi Formation in Baishan City, Jilin Province, China. The Baishan flora comprises 27 genera and 46 species. They are predominantly autochthonous or parautochthonous, based on their floral composition and taphonomic attributes. An analysis of paleoecological characteristics of the fossil plant assemblages, combined with the habitat preferences of analogous modern communities, allowed us to reconstruct the Early Cretaceous plant communities in the Baishan Basin: a riparian-wetland community, lowland community, montane slope community, and montane highland community. The floral composition, a statistical analysis of foliar physiognomy, and the palynofloral characteristics indicated a warm and humid temperate climate during the deposition of the Yingzuilazi Formation. A genus-level comparison with the Yixian Formation flora of western Liaoning revealed high compositional similarity, which confirms the Baishan flora as the easternmost distribution of the Jehol Biota in China. This study provides new fossil evidence for understanding Early Cretaceous floristic provincialism and paleoenvironmental reconstruction in East Asia. It offers geological references that can predict vegetation responses to a greenhouse climate. Additionally, Sphenopsida and Filicopsida may serve as potential indicators that may identify favorable terrestrial shale oil and gas reservoirs from the Early Cretaceous.

The Late Miocene locality of Achiri from the Bolivian Altiplano preserves a diverse mammalian fauna, of which the glyptodontids are represented by Trachycalyptoides achirense. Glyptodontids and other cingulates are valuable for palaeoecological analyses because their dermal armour provides an excellent substrate for the preservation of ichnofossils recording biotic interactions. We assessed the dermal armour of the holotype of Trachycalyptoides achirense, consisting of a caudal tube and various fragments of dorsal carapace, for evidence of trace fossils and identified the first evidence of both parasitism and faunivory for the Achiri fauna. Both the caudal and carapace armour preserves evidence of round holes that are variable in morphology but similar to those observed in fossil cingulates and modern armadillos and which have been linked to the action of fleas related to the modern hectopsyllid taxon Tunga perforans. These holes are assigned to the ichnotaxon Karethraichnus, expanding the record of this trace to the Late Miocene of Bolivia. Bite marks and linear grooves on the caudal armour preserve evidence of the consumption of meat, but are not severe enough to be considered evidence of predation. Instead, the most likely explanation is that they were emplaced during scavenging by the only known faunivore from Achiri, Borhyaenidium altiplanicus. The continued expansion of the trace fossil record associated with fossil cingulates will eventually allow for the potential of testing hypotheses based on modern parasites, including the relevance of predation pressure, resource availability and environmental variables (including precipitation and altitude) to parasite abundance and diversity.

The recognition of an additional component in the Thango Formation and new fossil evidence from the Takche Formation necessitate reclassification of the Sanugba Group. The Thango Formation is subdivided into the Yamrang La, Chango and Shian members, representing transgressive–paralic, beach and high-energy shallow-marine settings. The Takche Formation is divided into the Farrakha, Pin and Thanam Members, corresponding to mid- and outer-ramp, reefal and fore slope environments. Post-Kurgiakh Orogeny, marine transgression was diachronous, initiating in Kinnaur and advancing westward into Spiti and Zanskar, with the Takche Basin remaining shallowest in the east. Variations in sedimentary architecture reflect basement structures, notably the Chandra–Sarchu and Kaurik–Chango faults. During the Himalayan Orogeny, fault systems bounding the Tethyan Rift Basin were tilted, uplifted and displaced, transporting the overlying Tethyan sediments. This tectonic boundary fault is now recognised as the South Tibetan Detachment System (STDS).

Mimicry is an adaptive strategy widespread in modern ecosystems, yet its deep-time origins and evolution remain poorly understood due to the scarcity of unequivocal fossil evidence. Leaf mimicry has independently evolved in multiple insect lineages, reliable fossil evidence remains exceedingly rare and is primarily known from the Mesozoic and Cenozoic. We report a highly specialised cicadomorphan forewing from the Guadalupian Yinping Formation of China (ca. 260Ma) that exhibits a striking morphological resemblance to Sphenophyllum Brongniart, 1828, a groundcover widely distributed in late Paleozoic floras. An integrated assessment of wing morphology, geometric morphometric analysis, and the ecological association between the insect and the plant supports the hypothesis of mimicry. This finding enriches the Paleozoic record of leaf mimicry in insects, broadens our understanding of its evolutionary history in Hemiptera, and provides a rare perspective on insect-plant ecological associations in the South China Block before the end-Permian mass extinction.

BackgroundStipules are specialized appendages borne at the base of a leaf petiole and may perform a variety of functions including sheltering delicate growing tissues from environmental exposure, facilitating vegetative propagation and dispersal, and providing climbing hooks or protective spines. While stipules are widespread in extant angiosperms and a few fern groups, their origins in geological history remain poorly understood. This study critically reconsiders the absence of stipules in the ancestry of Marattiales.ResultsBased on extraordinary collections from the early Permian Wuda Tuff Flora, we report, for the first time, aphlebia fossils organically attached to psaroniaceous petioles. The psaroniaceous aphlebiae are homologous to marattiaceous stipules, as evidenced by numerous shared characteristics. Functionally, psaroniaceous stipules appear to shelter juvenile fronds and the stem apex, with a continued role in mature fronds. Furthermore, their continued and potentially indeterminate growth, along with their fully laminated structure, suggests a possible role in vegetative propagation after detachment from the parent frond. However, no direct fossil evidence of stipules acting as vegetative propagules is currently available.ConclusionsOur discovery provides unprecedented view of stipules in psaroniaceous tree ferns. The discovery of psaroniaceous stipules is significant, as it represents the earliest known stipule in the plant kingdom and underscores their multifunctional roles in plant development.

Fossil insects have been a key tool for understanding the phylogeny and evolutionary history of life. However, many regions of the world still exhibit significant gaps in the knowledge of insect fossils, with South America being particularly underrepresented. The limited understanding of the fossil record—encompassing diversity pools, types of fossil evidence, geological ages, and taxonomic identity—can lead to the undervaluation of this heritage and, in severe cases, to the material loss of specimens. This study aims to provide a systematic compilation of studies on Chilean fossil insects and a fossil checklist. A broad literature review was conducted, including scientific articles, books, theses, and conference papers, using keywords related to Chilean fossil insects. We included data of species identity, fossil type, stratigraphic context, age calibrations, and locality information. The resulting dataset comprised 93 works, including 65 primary and 28 secondary sources. We registered records from Quaternary, Neogene, Paleogene, Cretaceous, Jurassic, and Carboniferous periods. The Quaternary period had the most extensive coverage in terms of fossil records. A total of 726 nominal records (taxon and ichnotaxon names) of arthropod fossils were recorded, with Coleoptera the most diverse group. Additionally, 17 records of Araneae and one putative record for Myriapoda classes were registered. Finally, we critically evaluated the sources of information to confirm or dismiss some doubtful records, provide an overview of the current state of knowledge, and suggest considerations for the future development of this discipline in Chile. Future studies should consider new methodological approaches, validate the records through thorough phylogenetic and nomenclatural analyses, properly characterize the type of material and its compliance with current nomenclatural rules, and finally, provide an accessible repository to ensure the replicability of the studies.

Myanmar amber is famous worldwide for its abundant, exquisite, and diverse fossils (including those of flowers). However, the importance and value of this amber flora are still underappreciated. Here we report a group of well-preserved tiny seeds embedded in Myanmar amber. Many winged seeds are concentrated in a very limited space, revealing a high abundance and a great diversity of angiosperms previously unknown. There are another group of seeds probably from a single plant fruit, but they demonstrate variable wingless morphologies. The variable morphologies of these seeds indicate a previously unknown seed morphological plasticity of the mother plant. The common feature of all these seeds is their tiny size. The present discovery reflects that, during their mid-Cretaceous radiation, at least some taxa adopted a strategy similar to that of extant orchids.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-27211-6.

ABSTRACT The Hermann’s tortoise (Chersine hermanni), an endangered species, currently ranges from eastern Spain to the Balkans and some Mediterranean islands, though fossil evidence shows a wider past distribution. This study analyses the chelonian remains recovered from Buena Pinta Cave site (Middle to Late Pleistocene), the most complete with semi-articulated specimens from the Calvero de la Higuera Archaeological Complex (Pinilla del Valle, Madrid, central Spain). The morphology of these remains is consistent with C. hermanni. Taphonomic analysis suggests that carnivore activity and water transport were responsible for the accumulation of the assemblage. The nearly complete carapace from Unit 23 may represent an individual that died potentially naturally during brumation. The presence of Chersine hermanni at high altitudes in central Spain (~1,100 metres above sea level) during the middle and Late Pleistocene exceeds the current maximum elevation for the western subspecies (850 metres) and is more comparable to that recorded for the eastern subspecies (1,450 metres). These findings suggest the Iberian populations of C. hermanni had a broader ecological tolerance in the past, inhabiting higher-altitude areas and climatic conditions not currently found within its current range. These results highlight the importance of considering historical distributions when developing conservation strategies for endangered species.

First evidence of tubular fossils from the Anti-Atlas: Insights into the paleogeography of Late Ediacaran tubular fossils and the Ediacaran–Cambrian boundary in the Anti-Atlas

Unlike gymnosperms with naked ovules, angiosperms are defined and characterized by their enclosed ovules. According to plant evolution theories, angiosperms should be derived from their gymnospermous ancestors, which have naked ovules. Thus, an assumed transitional plant is expected to have started but not yet completed the enclosing of its ovules; specifically, some of its ovules are enclosed while others are not. This unusual expectation is, although rational, paradoxical: If this is so, is the plant a gymnosperm or an angiosperm? To date, such an expectation has never been met by any fossil evidence. The lack of favorable evidence makes the above expectation speculative and leaves evolutionary theorists vulnerable to attacks from their opponents. Here, I report a fossil plant, Lingyuanfructus hibrida gen. et sp. nov., from the Yixian Formation (Lower Cretaceous) of Liaoning, China, that meets this expectation. With young seeds both naked and enclosed in a single specimen, Lingyuanfructus defies any placement among seed plants and blurs the otherwise distinct boundary between angiosperms and gymnosperms, consolidating the foundation for evolutionary theory.

Both coelacanths and lungfish have fossil evidence dating back 400 million years, placing them at a critical evolutionary juncture when marine animals transitioned to terrestrial environments. An intriguing question lies in the extent to which their cognitive abilities had evolved before they crawled onto land. While no fossil DNA exist for extinct coelacanths or lungfish, studies on their extant species offer clues. Notably, the biological traits of coelacanths and lungfish have been remarkably stable over the past 70 million years, suggesting that some genomic regions in their genomic sequences possess exceptional stability. This raises the possibility of inferring their cognition gene polymorphism patterns (CGPPs) and evolutionary positioning through genomic analyses of modern samples. By employing 471 whole-genome sequence samples, including archaic humans (Neanderthals, Denisovans and more), modern humans, other vertebrates (fish, amphibians, reptiles, birds, rodents, mammals) plus four coelacanth and three lungfish samples, together with 18 human cognition-related genes and their total of 223 SNVs (Single-Nucleotide Variations),comparative analyses revealed that the CGPPs of both coelacanths and lungfish are evolutionarily closer to those of archaic humans than those of most other animal groups. The CGPP appears to occupy an evolutionary inflection point, bridging diverse animal lineages to archaic hominoids. Our observational results suggest a hypothesis (to be validated in the future) that the genetic architecture underlying human cognitionseemsto have beenestablished during the evolutionary stage of fish, predating the emergence of tetrapods.

Mucilage, a polysaccharide-rich substance secreted by root cap and border cells, is a key mediator of plant-soil interactions. This review traces the evolutionary origins of root mucilage from ancestral secretion mechanisms in streptophyte algae to its diverse roles in modern vascular plants. We highlight how mucilage biosynthesis relies on conserved gene families involved in polysaccharide assembly, whose phylogenomic distribution suggests that components of this machinery were already present in algal ancestors. Combining genetic, functional, and ecological evidence, we infer a stepwise evolutionary trajectory in which mucilage initially facilitated hydration and anchorage, later supporting soil structuring, plant-microbe interactions, nutrient availability, root water uptake, and drought tolerance. Fossil and comparative evidence indicates that both the secretion of mucilage and its regulatory mechanisms are deeply conserved traits. By connecting ancestral molecular and physiological functions to modern ecological roles, we demonstrate that mucilage has been a critical adaptation enabling plants to colonize and thrive in terrestrial environments over geological timescales.

BackgroundInsects have evolved various antipredator defenses, some of which produce copious chemicals when threatened, such as ants, beetles, butterflies, moths, stick insects, and true bugs. The true bugs (Hemiptera: Heteroptera) are known for their foul odor, which comprises over 45,000 species of biologically and economically important insects. One key element to the success of heteropterans is the evolution of specialized defensive glands, specifically the metathoracic scent gland in adults and the dorsal abdominal scent glands in nymphs, a hallmark synapomorphy for the clade. Within Pentatomomorpha, the scent gland peritreme exhibits remarkable morphological diversity, yet its evolutionary origins and drivers remain poorly understood due to sparse fossil evidence of these delicate structures.ResultsWe report a series of Mesozoic fossils with well-preserved scent gland anatomy, including the earliest evidence from the Jurassic (165 million years ago), revealing an ancestral auricle-type morphology. Ancestral-state reconstruction across 40 extant and fossil taxa confirms the auricle as the plesiomorphic condition for Pentatomomorpha. Fossil evidence demonstrates phenotypic diversification by the Early Cretaceous (~ 125 Ma), with many peritreme types (auricle, spout, groove) emerging by the mid-Cretaceous. Developmental analyses of extant taxa show no pre-adult differentiation, indicating rapid peritreme formation during the final molt.ConclusionsThe scent gland peritreme evolved as a rapidly developing from a simple underdeveloped to auricle to five well-developed basic derived types in early Pentatomomorpha. Its subsequent diversification into specialized forms coincided with mid-Mesozoic habitat shifts and predator pressures, particularly during angiosperm proliferation. Convergent morphologies across lineages reflect shared ecological constraints and developmental plasticity.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12915-025-02446-x.

ABSTRACT Anacondas (Serpentes: Eunectes) are among the largest extant snakes, reaching body lengths up to 7 meters, but the evolution of gigantism in anacondas and its environmental drivers is poorly understood due to a dearth of fossil evidence. Here we describe snake fossils from the middle to upper Miocene Socorro and Urumaco formations in Falcón State, Venezuela, consisting of the alethinophidian Colombophis, indeterminate boids, and multiple specimens of Eunectes. We use linear regression models of vertebral measures onto body length in snakes to estimate body size through time in the Eunectes record and compare results with modeled body lengths derived from Ancestral State Reconstruction (ASR) performed over a time-calibrated phylogeny of Boidae. Our results reveal total body lengths of 5.2 m (5.5–3.5 m) in Eunectes by 12.4 Ma, consistent with the timing in model estimates from ASR. The first occurrence of gigantism in Eunectes is concurrent with the establishment of the Pebas wetland system in tropical South America, and the evolution of giant body sizes in other aquatic reptiles. Unlike other giant taxa, which had body size maxima during the Miocene, followed by extinction and replacement with smaller-bodied taxa by the Pliocene, large Eunectes has persisted in tropical South America to the present.

ABSTRACT Hominin fossils and lithic evidence can, considered together, shed light on major changes in hominin evolution. Correlated changes in hominin fossil and lithic evidence appear at three major inflection points, ca. 3.4, 1.7, and 0.3 Ma. These inflection points mark evolutionarily consequential changes in hominin survival strategies.

SummaryMycorrhizal associations between fungi and plants are a fundamental aspect of terrestrial ecosystems. Mycorrhizas occur in c. 85% of extant plants, yet their geological record remains sparse. Rare fossil evidence from early terrestrial environments offers crucial insights into these ancient symbioses, but visualizing fossil fungi at the microscale within plant tissues is challenging.Here, we combine confocal laser scanning microscopy and fluorescence lifetime imaging microscopy (FLIM) to investigate a newly identified fungus and cellular structures of a 407‐Myr‐old plant from the Windyfield Chert, a stratigraphically distinct fossiliferous unit from Rhynie (Scotland). We also applied Raman spectroscopy to investigate the carbon framework of both fungal and plant tissues.This integrative approach revealed fungal structures in unprecedented detail. The fungus, Rugososporomyces lavoisierae gen. nov., sp. nov., exhibits features resembling extant Glomeromycotina arbuscular mycorrhizal fungi. This is the first record of mycorrhizas from the Windyfield Chert. FLIM further distinguished features at the subcellular level, while Raman spectroscopy showed that fungal arbuscules and vesicles of the plant water‐conducting cells underwent geological alterations, resulting in a similar chemical composition.These findings expand our understanding of ancient and extremely rare plant–fungal symbioses and highlight the potential of confocal‐FLIM for advancing palaeobotanical research.

Fossil evidence for trait diversification in an adaptive radiation

The zombie worm genus Osedax Rouse et al. 2004 is part of a peculiar group of organisms that thrive at whale fall localities on the ocean floor. In addition to feeding on whale bones, extant Osedax spp. are known to feed on the bones of other marine and terrestrial mammals, birds, and reptiles, and have recently been found to also feed on shark tooth dentine under experimental conditions. The efficacy of Osedax spp. as bioeroders is such that they are thought to have significantly affected both the quantity and the quality of the marine vertebrate fossil record. Here, we report on the occurrence of single-entry borings consistent with those produced by Osedax on fossil shark teeth from the Lower Pliocene offshore deposits of Tuscany, central Italy. Micro-CT investigations reveal that the worms excavated the dentine of the tooth roots, leaving the enameloid-coated crowns seemingly unaltered. The borings in question are assigned to the Osedax -related ichnogenus Osspecus Higgs et al., 2012, which to date had been found on a variety of marine vertebrate fossils, but not on shark teeth. This ichnological record provides the first fossil evidence for zombie worms exploiting shark tooth dentine and serves as a powerful demonstration that such behaviour can and does occur in the wild. Root exploitation by Osedax may contribute to explain the high frequency of rootless teeth in some shark tooth accumulations from modern deep-sea floors and time-averaged horizons inland. Over the past 100 million years, shark teeth have likely served as critical ecological stepping stones between remote marine vertebrate fall localities and may even have provided a suitable substrate for ancient zombie worms during the Cretaceous–Paleogene (K–Pg) extinction event.