The postcanine teeth of mangabeys (members of Cercocebus and Lophocebus) have figured prominently in discussions about the relationship between hard-object feeding and dental form. Grey-cheeked mangabeys (Lophocebus albigena) and sooty mangabeys (Cercocebus atys) both have thickly enameled posterior teeth. Thick enamel in the former is argued to be response to fallback consumption of hard-object foods, whereas in the latter, this feature is thought to have evolved in response to routine consumption of hard-object foods year-round. Our recent analyses reveal aspects of dental form beyond thick enamel that render C. atys posterior teeth better suited to process hard-object foods and resist fracture than those of L. albigena. We argue that the different feeding regimes of these two mangabey species had different effects on the evolution of their posterior teeth. Here, we detail these differences within the context of the fallback food paradigm. These results may ultimately help us detect modes of hard-object feeding in the fossil record.

A review of European Middle Pleistocene hominin evolution

Linking the Cretaceous and the Paleogene: Shallow-water stalked crinoids from Seymour Island reveal continuous Antarctic fossil record

We focus on three researchers-Davidson Black, Franz Weidenreich and Ralph von Koenigswald-who have made major contributions to the recovery of the fossil record of the hominin taxon now known as Homo erectus. Black was responsible for the recognition of Sinanthropus pekinensis and for the recovery of the initial hypodigm from Choukoutien*. Almost all of the original S. pekinensis fossils were lost during the Second World War, but the precise documentation and meticulous descriptions prepared by Franz Weidenreich substantially mitigate their loss. An earlier article in this series focused on Eugène Dubois' recovery of the type specimen of Pithecanthropus erectus from Trinil in Java, and while a few additional specimens from Trinil were recognized, the majority of the Javan hypodigm of P. erectus was recovered thanks to initiatives led or encouraged by Ralph von Koenigswald.

The legacy of the paleotropical flora belt: extreme continental vicariance and island refugia in Woodwardioid ferns.

Marine mud-dwelling meiofauna are both abundant and resilient. Their burrows are more likely to be preserved in cohesive mud than in granular substrates, and marine mudstones are common throughout geological time. Together, these factors suggest that meiofauna are significant contributors to the trace fossil record. However, the literature specifically addressing meiofaunal bioturbation is limited. This manuscript reviews the existing meiofaunal bioturbation literature and integrates relevant findings from adjacent research areas, including studies on cryptic bioturbation and interpretations of massive-appearing bedding. Specifically, we: (1) synthesize burrowing strategies used by common marine meiofauna and their resulting trace morphologies; (2) critically examine previously recognized meiofaunal traces within mudstones; and (3) propose best practices for describing and quantifying meiofaunal microburrows. Meiofauna use varied locomotion strategies—such as ciliary gliding, undulation, peristalsis, and complex digging—whose effectiveness depends on organism size, locomotion speed, and the mechanical properties of mud substrates ranging from viscous to elastic. These locomotion behaviours produce distinctive microburrow morphologies, usually identifiable only through petrographic or SEM analyses as subtle disruptions to sediment fabric. Due to the absence of standardized nomenclature for microburrows, we advocate morphological descriptions over assignment to existing ichnogenera.

This contribution describes and discusses the first fossil record of a male imago belonging to the genus Ecdyonurus Eaton, 1868 (Ephemeroptera, Heptageniidae). The features of the genitalia, with the characteristic structure of the not projected apical sclerite of the penis lobes curved laterally, undoubtedly indicate its belonging to the subgenus Helvetoraeticus Bauernfeind & Soldán, 2012. Ecdyonurus (Helvetoraeticus) hoffeinsorum sp. nov. is established for a single adult specimen from the Eocene Baltic amber, and its taxonomical relationships are analysed. Furthermore, based on the unique structure of the mesonotal lateroparapsidal suture, we raise Nestormeus stat. nov. (formerly a subgenus of Ecdyonurus comprising two Eocene species, i.e. Nestormeus leopoliensis (Godunko, 2004) comb. nov. and Nestormeus groehnorum (Godunko, 2007) comb. nov.) to the genus level. The extant species of the subgenus Helvetoraeticus are known from Western Palearctic only, based on adults and obligatory rheophilous larvae inhabiting water courses of different types in the mountainous and foothills regions of Europe, Minor Asia and the Caucasus. Well-grounded description of a fossil representative of the rheophilic subgenus Helvetoraeticus in the Cenozoic resin of Europe is significant for future precise reconstructions of the ecological and biogeographic patterns of the freshwater Eocene fauna, as well as a reliable calibration point for time scaled phylogeny reconstructions. Given the lack of knowledge on the molecular diversity of Ecdyonurus genus, significant morphological variability of all life stages, the presence of endemic and potentially cryptic species, and insufficient knowledge of the distributional pattern of most Helvetoraeticus representatives, we analyse the available data on the genetic structure of the Ecdyonurus genus revealing high diversity and putative misidentifications, underscoring the taxonomic challenges within this group.

The Mesozoic fossil record of Cupressaceae is widespread and abundant, indicating that members of the family were dominant components of ancient ecosystems and that several cupressaceous lineages had higher species diversity in the past than they do today. Despite this extensive record, anatomical evidence remains critical to understanding the evolution of the group. This study provides new insights into the early evolutionary history of Cupressaceae and their adaptations to Jurassic environments through exceptionally preserved fossils from Patagonia. Silicified leaves and twigs were collected from chert deposits at the Claudia and Cañadón Nahuel localities (La Matilde Formation, Santa Cruz Province). Samples were cut, polished, and analyzed using light microscopy and image-stacking techniques. Morphological, cuticular, and anatomical characters were compared with extant and fossil Cupressaceae to assess affinities. The leaves are dorsiventrally flattened and helically arranged with a semiplanar orientation. Anatomical features include a single abaxial resin canal and transfusion tissue surrounding the vascular bundle adaxially and expanding laterally into two rounded lobes. Cuticular traits include abaxial, monocyclic stomata with subsidiary cells resembling adjacent ordinary epidermal cells. These features align with Austrohamia and indicate affinity with Cupressaceae s.l. The combination of vegetative, cuticular, and anatomical features supports assigning these Jurassic Patagonian fossils to Austrohamia and suggests a position near the root of Cupressaceae s.l. Their remarkable histological preservation provides new anatomical and biostratigraphic data, enhancing understanding of the early evolution of this family.

Abstract. Evolutionary developmental biology seeks to elucidate the developmental mechanisms underlying phenotypic evolution. Central to this endeavor is the quantitative analysis of morphological variation, for which morphometric approaches have become indispensable tools. While morphometric methods have been extensively applied in paleontological research across diverse fossil groups, certain taxa remain underexplored. Among these, ostracods (Crustacea) represent a particularly promising yet underutilized group for such analyses. The suitability of ostracods for evolutionary and developmental investigations stems from several key attributes: their near-ubiquitous distribution across aquatic habitats, a remarkable taxonomic and morphological diversity, and an exceptional fossil record spanning geological time scales. Traditional morphometric approaches are constrained by the time-intensive nature of data acquisition, limiting the extent of achievable datasets. To address this bottleneck, we evaluate the efficacy of AutoMorph, a high-throughput imaging pipeline, for automated extraction of size and shape data from ostracod valves. We apply this approach to two ostracod species, Leucocythere dorsotuberosa and Leucocytherella sinensis, sampled from six lakes across the Tibetan Plateau, a region offering aquatic ecosystems with high endemism, providing an ideal setting for investigating ecological and evolutionary responses through morphological approaches. Our findings demonstrate that the AutoMorph pipeline successfully extracts morphometric measurements and coordinate data from ostracod valves, substantially reducing processing time while minimizing subjective bias inherent in manual approaches. This methodological advancement facilitates the generation of extensive datasets, thereby enabling more comprehensive investigations of ecological and evolutionary processes on large spatial and temporal scales.

ABSTRACT The Neogene lizards are poorly documented in the Indian subcontinent so far, which hinders our understanding of their evolutionary and biogeographic history in the region. In this paper, we report a few fossil lizards from the Late Miocene deposits of the Dunera locality in Punjab. These fossils have been identified as cf. Uromastyx sp. Agamidae indet. and Scincidae indet. Notably, the skink discovered in this study represents the first fossil record of its kind in the Siwaliks. Also, fossil evidence of Uromastycinae in the Indian Subcontinent suggests that its diversification occurred during the Miocene. The co-occurrence of the agamid cf. Uromastyx sp. and the skink in this area indicate a cold and drier climatic condition at that time. Despite the limited materials, these findings significantly enhance our understanding of the past diversity and biogeography of lizards in India.

The Neogene fossil record of predatory mammals indicates periodic dispersals across the Beringian land bridge. Among the documented immigrant species in the weasel family (Mustelidae), Cernictis hesperus is among the most poorly known genotype species because of the highly fragmentary holotype. Here I report a new specimen representing the species from its type locality in the Pinole Tuff Formation, California. Associated left and right dentaries show that C. hesperus possesses a first premolar, unlike all other known species of the genus. Furthermore, incisor alveoli indicate the presence of a full incisor toothrow that is similarly crowded compared to the cheek teeth. These new morphological characteristics improve the diagnosis of the genus and species for the first time in nearly a century since the initial publication on the taxon.

The forelimb and hindlimb of tetrapods are serially homologous structures that share a conserved developmental framework. Despite their evolutionary divergence in form and function, the two sets of limbs retain parallel genetic and morphogenetic patterning, enabling comparisons across and within species. While serial homology has been well established for proximal limb elements (i.e., girdle and long bones), the mesopodium (the carpals and tarsals) has received comparatively little attention. This gap is due in part to the morphological complexity of these regions and the absence of a clear, consistent framework for one-to-one comparison. In this paper, we present a framework for morphological comparisons between the limbs by proposing explicit serial homologies between individual carpal and tarsal elements. Building on Owen's classical criteria of homology (i.e., composition, relative position, and development), we integrate evidence from comparative anatomy, embryology, and the fossil record to justify specific pairings. In doing so, we extend previous efforts that relied primarily on gross morphology by incorporating developmental timing, positional shifts, and patterns of fusion and reduction of elements observed across taxa. This proposed framework enables new comparative analyses of the mesopodium, with implications for future studies of covariation, modularity, and functional-adaptive evolution, expanding the anatomical toolkit for addressing long-standing questions in vertebrate limb evolution. By refining the criteria for mesopodial homology, this work contributes to a more complete understanding of integration between sets of limbs and their process of evolutionary divergence in tetrapods.

Sauropod dinosaur remains comprise the majority of the Mesozoic vertebrate fossil record in Thailand. However, they are rare and fragmentary in the Aptian–Albian (Lower Cretaceous) Khok Kruat Formation, the stratigraphically youngest fossil-bearing Mesozoic Thai stratigraphic unit. Based on a partial postcranial skeleton, we present the first diagnostic sauropod specimen from this formation, which represents a new somphospondylan titanosauriform, Nagatitan chaiyaphumensis n. gen. n. sp. Nagatitan is diagnosed by two autapomorphies and a unique character combination, including the presence of two distinct hyposphene-hypantrum morphologies within the middle–posterior dorsal vertebrae. Phylogenetic analyses under maximum parsimony, using a data matrix containing 153 taxa and 570 characters, produce well-resolved topologies that place Nagatitan within the somphospondylan clade Euhelopodidae. Nagatitan does not form an endemic subclade with the approximately contemporaneous Southeast Asian euhelopodids Phuwiangosaurus and Tangvayosaurus, with a suite of anatomical features distinguishing these taxa. We estimate a body mass of 25–28 tonnes for Nagatitan, and suggest it was part of a broader middle Cretaceous body size increase in Asian titanosauriforms, facilitated by rising temperatures and expanded suitable habitat. The discovery of Nagatitan expands the known diversity of Southeast Asian sauropods and improves our understanding of titanosauriform biogeography within the region.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-026-47482-x.

Time-calibrating a phylogenetic tree is a fundamental step in phylogenetic inference, as it allows the study of macroevolutionary processes such as lineage diversification, trait evolution and historical biogeography. To this end, the fossilized birth-death (FBD) process, a stochastic process that coherently integrates fossils into phylogenies, is increasingly used as an alternative to traditional ad hoc node-calibration densities. However, the effective prior distribution on node ages induced by the FBD has never been investigated before, hindering an informed choice between the two approaches. Here, we analyse two empirical datasets (crocodylians and fireflies) by applying several models of time-calibration, including traditional node calibrations and FBD. We show that the effective node age priors induced by the FBD process in the absence of morphological data are comparable to those induced by flat node calibrations when only the oldest fossil occurrence per calibrated clade is included in the FBD analysis. However, effective node age priors become more informative when several fossil occurrences per calibrated clade are included. Our exploration sheds light on how palaeontological information is translated to node ages by the FBD process, and suggests that node calibration approaches remain an important alternative when the fossil record of the studied group is scarce and other prior information can be used to devise informative calibration densities.

In stem mammals, feeding and hearing are closely linked due to jaw bones being involved in both functions. Osteological changes during the evolutionary separation of these systems are well documented in the fossil record, but changes to soft tissue anatomy are less certain. The medial pterygoid muscle is a jaw adductor that develops medial to Meckel's cartilage, inserting on the mandibular angular process in therians (placentals and marsupials). Likewise, in stem mammaliaforms, the medial pterygoid is often assumed to have passed medial to the ossified Meckel's cartilage, inserting on the dentary 'angular' (i.e., pseudangular) process, a plesiomorphic pattern of muscle attachment also assumed to be present in some derived cynodonts. Thus, the traditional interpretation is that the medial pterygoid remained medial to Meckel's cartilage through the evolution from early cynodonts to therians. We highlight a pattern that contrasts with that interpretation: the medial pterygoid inserts lateral (not medial) to Meckel's cartilage in monotremes. Further, fossil evidence suggests that this pattern was also present in stem therian eutriconodontans and spalacotherioids, which lack the pseudangular process, suggesting that the muscle is either 1) evolutionarily labile in terms of its relative position to Meckel's cartilage, or 2) did not insert on the pseudangular process of early cynodonts. We support the latter hypothesis, proposed by Patterson (1956), which indicates that the medial pterygoid did not shift medial to Meckel's cartilage until the complete ear-jaw separation in cladotherians (therians and close relatives), with the shift linked to the evolution of the therian angular process as an insertion site.

Forty years of phylogenetic analysis have failed to resolve the relationships among the major groups of seed plants. From the fossil record it is clear that more seed plant groups have gone extinct than are extant, though some direct ancestors of today's clades could have survived. Here we reanalyze morphological matrices relevant to seed plants, applying two underutilized visualization tools: Networks for displaying incompatible phylogenetic signal and Romerograms (spindle diagrams) for depicting alternative relationships, suspected budding speciation, and surviving ancestors. Surviving ancestors give rise to hard polytomies, and networks may help pinpoint them as suggested by experiments in which we added simulated ancestors to our matrix. Romerograms - whose reproducible construction we illustrate - offer a heuristic means of representing phylogenetic hypotheses, and we argue that the field's near-exclusive focus on identifying sister groups and representing them in cladograms may have driven phylogenetics into an impasse. Identifying true evolutionary polytomies warrants further methodological research, but broadening the repertoire of data visualization approaches may help overcome the field's entrenched bias toward strictly dichotomous trees.

The Eocene radiation of cetaceans marks the evolutionary transition of whales from amphibious ancestors to fully aquatic forms within the clade Pelagiceti. Here we report the first fossil record of an Eocene whale from Poland, represented by a fragmentary posterior portion of a left dentary recovered from glauconitic sands of the Siemień Formation near Lubartów (eastern Poland). Biostratigraphic data based on calcareous nannoplankton and dinocyst assemblages place the fossil-bearing deposits near the Bartonian-Priabonian boundary (~38 Ma) within the epicontinental Central European Basin. The specimen preserves several closely spaced alveoli corresponding to double-rooted molars and a robust posterior dentary crest interpreted as a muscle attachment site, allowing referral to Pelagiceti indet. Comparative analysis of alveolar dimensions suggests that the animal was small-bodied, with an estimated total length of approximately 1.7-2.1 m. This size places it among the smallest known fully aquatic Eocene whales and indicates the presence of dolphin-sized pursuit predators in late middle Eocene marine ecosystems. The occurrence of such a small pelagic cetacean alongside large macropredatory basilosaurids supports the hypothesis that significant ecological and body-size differentiation within Pelagiceti had already developed by the Bartonian-Priabonian transition. Paleogeographically, the Polish locality occupied a central position within a shallow epicontinental seaway connecting the North Sea Basin with the eastern Tethyan realm. The new record therefore fills a key geographic gap between western and eastern European occurrences of Eocene whales and supports the existence of dispersal pathways across the Central European Basin during the early global expansion of fully aquatic cetaceans.

Vertebrates are unique among animals as they bear a neurocranium, which almost completely encapsulates the brain. Thus, within vertebrates, the evolution of neuroanatomical features might be tightly correlated with the evolution of their surrounding neurocranial ossifications, as these pose spatial constraints to brain size and shape. The endocranial cast, or surrounding neurocranial ossifications, poses spatial constraints to brain size and shape. The endocranial cast, or 'endocast', represents an important structure for the study of vertebrate neuroanatomical evolution as it has been considered to be closely associated with brain morphology. This assumption has been tested for many extant vertebrate lineages, including archosaurs, mammals and non-tetrapod sarcopterygian fishes, but brain-endocast correlation has never been studied for ray-finned fishes. Given that ray-finned fishes represent roughly half of extant vertebrate diversity and show remarkable morphological disparity, understanding the relationship between brain and endocast in this major vertebrate lineage becomes paramount for understanding vertebrate neurocranial evolution. Here, we describe previously unknown morphological diversity of endocasts in extant ray-finned fishes, compare it to endocasts from the fossil record and explore the relationship between endocast and brain across a large sample of extant taxa. Our results indicate that endocasts are a poor predictor of brain morphology for ray-finned fishes but can provide valuable information regarding neurocranial diversification and its ties to ecological features.

ABSTRACT Burrower bugs (Cydnidae) have an extensive fossil record from the Lower Cretaceous to the Lower Miocene, but only the subfamily Amnestinae is described from the Cretaceous, with 14 known species. Here, we describe a new genus and species of Amnestinae, Eurydicoris tabulatus gen. et sp. nov. from the Crato Formation (Lower Cretaceous, upper Aptian), Santana Group, Araripe Basin (northeastern Brazil). The identification of the specimen is based on morphological data obtained from observations made with a binocular stereomicroscope, SEM micrographs, and micro-CT scanning. The new taxon differs from all other amnestines by a long ostiolar peritrema that is slightly curved anteriorly (auricle-shaped), and by the combination of a rostrum reaching the metacoxae, anteriferous tubercles arising in the interocular portion, reduced mesopleural evaporatorium, large metapleural evaporatorium occupying almost half of the metapleural surface and meso- and metacoxae situated closer together than to the procoxae. http://zoobank.org/2DE5899B-D996-4DA4-8F10-B4F581476E37

Limitations of molecular dating using constant birth-death rate priors in deep time reflected in Brachiopoda evolution.