The software evaluation used five public datasets from the ESRF Palaeontology database, covering different fossil types, scan resolutions and imaging conditions. The tests included complete Thrinaxodon and Broomistega skeletons from the Early Triassic Karoo Basin of South Africa, scanned at 45.5 µm resolution; a Middle Triassic Nothosaurus marchicus skull from the Netherlands, scanned at 12.82 µm; two Late Cretaceous paddlefish, Parapsephurus willybemisi, scans from North Dakota, at 45.53 and 13.67 µm; and an Early Cretaceous squamate embryo from an egg at Phu Phok, Thailand, scanned at 5.06 µm.

X-ray tomography can reveal anatomy concealed by surrounding matrix without physically preparing the specimen, but the resulting three-dimensional volumes demand substantial storage and computing resources. Manual segmentation and modelling can take months or years, and some projects remain unfinished. The ml4paleo package combines traditional machine-learning tools, neural image-segmentation options and batch processing. Its web interface supports machine-guided annotation of two-dimensional slices, while a conversion queue reorganises large image stacks into chunked volumes that can be processed without loading complete datasets into memory.

Workers apply a trained model to subvolumes, save segmentation masks and optionally produce OBJ or STL meshes for rendering in three-dimensional software. The package uses the Zarr format for chunked storage and lazy loading. Its default algorithm is a random forest trained on heuristic pixel features such as texture, intensity and edge information; by default, 50% of available annotated pixels are sampled during training. A convolutional residual U-Net is also available, although efficient training of that model requires a GPU. The interfaces are designed so that other specialised algorithms can be added.

One palaeontological segmentation expert initially annotated 20 slices from each dataset. The Nothosaurus and Phu Phok Egg volumes required 10 additional annotated slices and model retraining, followed by a final five slices, giving 35 annotations for each. A saved model could generate a proposed segmentation for subsequent annotation tasks, allowing the annotator to correct an existing mask with a brush or eraser rather than begin from scratch. The authors reported that replacing the default random forest with a neural model resolved many failures in the two difficult datasets, at the cost of additional execution time and GPU requirements.

On the Burrow dataset, which had relatively clear contrast between fossil and matrix, the random-forest model achieved precision of 0.861 ± 0.142, recall of 0.726 ± 0.154 and F1 score of 0.777 ± 0.129. Accuracy was 0.982 and the Jaccard index was 0.759, indicating substantial overlap between predicted and expert-annotated masks. These results came from sampled slices and five datasets, rather than from every fossil scan.

Performance varied for the paddlefish. At 13.67 µm, precision was 0.583 ± 0.298, recall was 0.492 ± 0.278 and F1 score was 0.488 ± 0.257; visual inspection indicated that the model generally captured gross morphology but did not correctly segment internal bone volumes. At 45.53 µm, precision was 0.718 ± 0.427, recall was 0.191 ± 0.187 and F1 score was 0.185 ± 0.181. Accuracy was 0.979, although the model tended to confuse bone with other bright objects and captured relatively little of the fossil.

The Nothosaurus dataset produced precision of 0.602 ± 0.227, recall of 0.496 ± 0.264 and F1 score of 0.522 ± 0.24. The authors linked the weaker result to the low-contrast texture and a crack through the skull that affected phase contrast. The Phu Phok Egg dataset was the most difficult for the default model: precision was 0.401 ± 0.295, recall was 0.020 ± 0.014 and F1 score was 0.035 ± 0.027. Visual assessment showed poor segmentation, with the model interpreting some high-phase-contrast edges as bone. Additional annotation increased Phu Phok precision from 0.232 at 20 slices to 0.401 at 35 slices, while recall changed from 0.06 to 0.02.

The comparisons also documented the time required for manual segmentation: more than six weeks of full-time work for the Nothosaurus, approximately eight weeks for the Phu Phok Egg and two weeks for the paddlefish scans. The Burrow volume was segmented relatively quickly using simple intensity thresholding. The authors present ml4paleo as an accessible option for groups without commercial software, but the evaluation showed that its default model was not equally suited to every specimen, especially where contrast, texture or resolution limited distinguishability. The code is released under the Apache 2.0 licence, the tested datasets are available through the ESRF Palaeontology database, and a public version of the service is available at ml4paleo.com.

Subject of Research: Evaluation of an open-source machine-learning pipeline for segmenting synchrotron X-ray tomography volumes of fossils

Article Title: Automated segmentation of synchrotron-scanned fossils

Article References: During, M. A. D., Matelsky, J. K., Gustafsson, F. K., Voeten, D. F. A. E., Chen, D., Wester, B. A., Kording, K. P., Ahlberg, P. E., & Schön, T. B. (2025). Automated segmentation of synchrotron-scanned fossils. Fossil Record, 28(1), 103-114. https://doi.org/10.3897/fr.28.139379

Image Credits: AI Generated

DOI: 10.3897/fr.28.139379

Keywords: fossil imaging, synchrotron tomography, image segmentation, machine learning, palaeontology, open-source software, X-ray tomography, 3D modelling, Automated, segmentation, synchrotron-scanned, fossils

The researchers examined seven stratigraphic sections arranged broadly from oldest to youngest: Mas dels Coixos, Mas de Torner, Araia Cantera Sud, Barranc de Campisano, Foieta la Sarra, Mas d’Antolino B and Corral de Brisca. The approximately 100-m-thick Campisano Ravine sequence in Unit Three of the basin comprises grey and yellow mudstones, limestones and sandstones.

The deposits had previously been assigned broadly to regional biozone C in the early Aragonian MN4 interval, covering approximately 16.5 to 15.94 million years ago. An alternative interpretation places the boundary between the local Ligerimys florancei and L. ellipticus biozones at the MN4–MN5 transition, so the precise chronological placement of the younger deposits remains a subject of debate.

This was a descriptive palaeontological study of fossil material housed at the Natural History Museum of the University of Valencia. Dental measurements were recorded in millimetres with a binocular microscope, mechanical stage and measuring device, while scanning electron microscopy was used to image specimens. The authors compared the upper and lower molars of Megacricetodon primitivus, Democricetodon decipiens and Eumyarion weinfurteri with reference populations from European and Turkish localities.

Megacricetodon primitivus and Democricetodon decipiens were the most abundant taxa and occurred at nearly all sampled localities, but their representation differed through the sequence. Megacricetodon predominated in the older L. florancei biozone, whereas Democricetodon became increasingly common in the younger L. ellipticus biozone and was the dominant muroid at MAB11 and CBR0B. Eumyarion weinfurteri was confined to FS1, MAB3 and MAB5 in the younger biozone. Melissiodon was represented by five remains from BC1 and MAB3, some of them incomplete, and one M2 from MAB0A could not be identified below Muroidea.

The dental analysis supported the assignment of most material to Megacricetodon primitivus, Democricetodon decipiens and Eumyarion weinfurteri. The Megacricetodon specimens were generally smaller than several other species of the genus and differed from M. collongensis in features including the frequency of divided anteroconids, loph development and protoloph and metaloph patterns. The authors concluded that M. primitivus remained broadly stable in size and morphology through time, despite variation among localities and slight tendencies in individual dental dimensions and features such as mesolophid development.

The Democricetodon material was assigned to D. decipiens because its morphology and measurements fell within that species’ variability. It was generally larger than the reference D. hispanicus sample, smaller than D. moralesi and similar in size to comparative D. decipiens and D. franconicus material. The identification of Eumyarion was less straightforward because of extensive variation within the genus and differing treatments of E. weinfurteri and E. latior. Under the diagnostic framework used by de Bruijn, the basin material was assigned to E. weinfurteri, although it was slightly larger than that species’ type population.

The five Melissiodon remains were left under open nomenclature because the sample was too limited for a formal species assignment. The material was smaller than MN1–MN3 populations and within the reported size variation for MN4. The lower first molar from MAB3 had an isolated mesolophid and direct contact between the posterior metalophulid and entoconid, a combination not reported in another population. Although Melissiodon has traditionally been interpreted as frugivorous, its slender mandible, weak incisors and delicately ridged teeth resemble those of insectivorous rodents; the authors therefore regarded an insectivorous diet as plausible. Its association with karstic deposits also led them to suggest a preference for less-wet upland habitats.

The abundance patterns provide a biostratigraphic and ecological framework for the sequence, but the proposed links between rodent representation, climate and vegetation are associations rather than direct experimental results. The older L. florancei deposits were interpreted as comparatively arid and open, with Megacricetodon more abundant, while the younger L. ellipticus deposits were described as more humid and forested, with more Democricetodon. On this basis, the coastal Ribesalbes-Alcora Basin was interpreted as a transitional region between the forested areas of western and central Europe and the drier interior basins of Iberia. The analysis is bounded by fragmented remains, uncertain assignments for Melissiodon and the indeterminate tooth, unequal representation among localities, and continuing debate over the taxonomy and evolutionary history of several muroid groups.

Subject of Research: Morphological and biometric analysis of Early Miocene muroid rodent fossils from Spain’s Ribesalbes-Alcora Basin

Article Title: The Early Miocene muroids ( Muroidea , Rodentia ) of the Ribesalbes-Alcora Basin (Spain): A thriving haven during a time of migration

Article References: Crespo, V. D., Ríos, M., Marquina-Blasco, R., & Montoya, P. (2025). The Early Miocene muroids (Muroidea, Rodentia) of the Ribesalbes-Alcora Basin (Spain): A thriving haven during a time of migration. Fossil Record, 28(1), 187-218. https://doi.org/10.3897/fr.28.138478

Image Credits: AI Generated

DOI: 10.3897/fr.28.138478

Keywords: Early Miocene, muroid rodents, palaeontology, fossil teeth, biostratigraphy, Ribesalbes-Alcora Basin, Megacricetodon, Democricetodon, Eumyarion, Melissiodon, Early, Miocene

The study treats UCMP 164865 as the anterior portion of a reconstructed left dentary. Its mandibular symphysis measures 2.4 centimetres and extends posteriorly to the fourth dentary alveolus. The dentary curves deeply between the fourth and twelfth alveoli, with a noticeable dorsal rise between the eleventh and twelfth. Although the splenial bone itself is absent, a preserved scar on the lingual surface indicates that it formed the medial wall of the anterior mandibular ramus and participated in the jaw symphysis.

Seven teeth are partly or wholly preserved in the specimen, together with evidence from the alveoli. The teeth project dorsally or anterodorsally, are unserrated and bear anterior and posterior carinae. They also show varying degrees of labiolingual compression, while the twelfth tooth is distinctly globidontan. Deeply furrowed basiapical striations occur on the lingual surfaces of the teeth. The authors note that these dental striations are particularly evident in several Eocene orientalosuchins, including Krabisuchus, Orientalosuchus and Dongnanosuchus, although the Oregon specimen itself is not established as an orientalosuchin.

No individual observed or inferred character establishes membership in Alligatoroidea by itself. The assignment instead rests on a combination of features, including a short dentary symphysis, deep dentary curvature, a splenial that participates in the mandibular symphysis, smooth tooth carinae and the globidontan posterior tooth. Comparisons with contemporaneous North American alligatoroids found distinctions that separate the specimen from late Eocene Alligator, Allognathosuchus, Procaimanoidea, Ceratosuchus burdoshi, Ahdeskatanka russlanddeutsche and Chrysochampsa mlynarskii.

The jaw is dated within a constrained interval of 42.7 to 39.677 million years ago by radiometric ages associated with the quarry strata. This range places the site in the latest Uintan or Duchesnean North American Land Mammal Age, described in the study as late Lutetian or Bartonian. The quarry contains a concentration of disarticulated large mammal skeletons that was probably deposited in a point bar of a meandering river channel. It is the only published vertebrate quarry deposit in the John Day Basin and preserves mammals, plants, fish, amphibians and reptiles.

UCMP 164865 shares a particular combination of three characters with Dongnanosuchus hsui and Alligator olseni: a short dentary symphysis, a deeply curved dentary and a splenial participating in the symphysis. Its lingual dental striations further resemble those of several Eocene orientalosuchins. These similarities make membership in Orientalosuchina possible, but the limited anatomy of the specimen prevents a more exclusive taxonomic assignment. The authors therefore retain alligatorines, caimanines, orientalosuchins and other alligatoroid branches as possible placements.

The geographic setting also raises questions about the specimen’s affinities. Eocene alligatoroids are common east and south of the Rocky Mountains but are virtually absent farther west, apart from this Oregon occurrence. The uplift of the Rockies during the Laramide Orogeny may have restricted crocodylian dispersal by the Uintan. In contrast, the authors note repeated faunal exchange between East Asia and North America through Beringia, providing a possible route for an orientalosuchin to reach western North America.

Other fossils from the Hancock Mammal Quarry show Asian connections. Five of the 14 mammalian genera represented there—Harpagolestes, Teletaceras, Eubrontotherium, Plesiocolopirus and Zaisanamynodon—also occur in parts of Asia during the middle Eocene. The tortoise Hadrianus from the slightly older Clarno Nut Beds is likewise known from the early Eocene of Asia. Approximately 40% of the genera in the Nut Beds flora occur in Eocene floras of Europe and Asia, a pattern interpreted as evidence for a connected mid-latitude Northern Hemisphere forest.

The report also figures UCMP 164866, a 10.5-centimetre right humerus from the upper Clarno Formation. It is presented as representative eusuchian postcranial material and is not assumed to belong to the same taxon or individual as the dentary, although their relative sizes do not rule out that possibility. Overall, the partial jaw adds a distinct and geographically unusual alligatoroid to the known record of Eocene North America, but its precise placement and any relationship to Asian orientalosuchins remain unresolved.

Subject of Research: Description and classification of a middle Eocene alligatoroid jaw from Oregon

Article Title: Small, enigmatic alligatoroid from the Middle Eocene Clarno Formation, John Day Fossil Beds, Oregon

Article References: Stout, J. B., Massonne, T., Samuels, J. X., & Schubert, B. W. (2025). Small, enigmatic alligatoroid from the Middle Eocene Clarno Formation, John Day Fossil Beds, Oregon. Fossil Record, 28(2), 309-319. https://doi.org/10.3897/fr.28.169148

Image Credits: AI Generated

DOI: 10.3897/fr.28.169148

Keywords: Alligatoroidea, Eocene, Clarno Formation, John Day Fossil Beds, Hancock Mammal Quarry, palaeontology, crocodylian, lower jaw, Oregon, Orientalosuchina, Small, enigmatic

Researchers recovered ML2631 from the Zimbral vertebrate microfossil assemblage near Lourinhã, where fossils occur in grey marls and silty mudstones interpreted as low-energy floodplain or lagoonal deposits. The specimen comprises a partial skull table and braincase preserved in a calcareous nodule. Its age is constrained to the upper Kimmeridgian–lower Tithonian, at the transition between those stages of the Late Jurassic.

This palaeontological study combined mechanical preparation, high-resolution micro-computed tomography, anatomical comparison, neurosensory estimation and parsimony-based phylogenetic analysis. Because matrix and dense mineral veins obscured parts of the skull, the researchers used micro-CT to segment the preserved anatomy. The scan produced 736 images with a voxel size of 0.049038 mm, although mineralisation created artefacts that complicated reconstruction.

Despite those artefacts, the team digitally reconstructed most of the skull, a nearly complete brain endocast, parts of both inner ears, several cranial nerves, part of the left internal carotid artery and most of the left paratympanic sinus system. The reconstructed brain has the sigmoidal profile reported in mesoeucrocodylians, with estimated cephalic and pontine flexure angles of approximately 150 and 145 degrees, respectively. The rhombencephalon accounts for about 55–60% of total brain length, a proportion the authors associated with neurocranial maturity.

The preserved inner ear was incomplete, although the left side was nearly complete and was combined with the anterior half of the right side in a tentative reconstruction. Its elevated anterior semicircular canal and tall, slender crus commune resembled conditions described in fully terrestrial crocodylomorphs. However, moderate canal thickness and the absence of a dorsoventrally compressed labyrinth were also compatible with eusuchians and living crocodylians. The authors therefore described the vestibular anatomy as intermediate between terrestrial and semi-aquatic forms, rather than treating it as direct proof of terrestrial locomotion.

Auditory capacity was estimated from an approximately 4.01 mm endosseous cochlear duct and an approximately 40.13 mm basicranial length, producing a logarithmic ratio of −1. This approximate result falls within the reported ranges for allodaposuchids and crocodylians and suggests adaptation for detecting low-frequency sounds. The authors noted that the cochlear region and pterygoid–palatine suture are poorly preserved, making both measurements uncertain. Olfactory capacity and the Reptile Encephalisation Quotient could not be calculated because the olfactory bulbs and body-mass proxies were unavailable.

Visual acuity was assessed by comparing reconstructed brain regions. The estimated total brain volume was 1,716.02 mm³, while the mesencephalon measured 154.2 mm³, or 8.98% of the total. This ratio is closer to the lower end of the range reported for large living crocodylians than to the higher ratios typical of smaller individuals. The authors suggested that ML2631 may therefore have been a fully grown, dwarf individual, although its ontogenetic stage could not be established securely. Comparisons with more complete atoposaurid skeletons produced a rough total-length estimate of 0.5–1 metre, probably near 0.8 metres.

The phylogenetic matrix contained 81 taxa and 321 characters. All searches recovered 30 most parsimonious trees of 1,489 steps and a strict consensus in which ML2631 was placed within Atoposauridae, between Knoetschkesuchus and Sabresuchus. Including the specimen resolved polytomies in the earlier analysis, but most internal nodes had Bremer values of 1 and bootstrap support below 50%. The Varanosuchus–Aprosuchus pairing was the exception, with a Bremer value of 6 and 83% bootstrap support.

ML2631 preserves a dorsolaterally open cranioquadrate passage, large supratemporal fenestrae with posterior fossae, a posteriorly placed septate choana and a discontinuous groove on the squamosal lobe. This combination was not matched by any known atoposaurid species and supports the possibility that the specimen represents a distinct taxon. Nevertheless, the authors retained the open designation Atoposauridae indet. because the missing teeth, much of the snout, palate and postcranial skeleton prevent adequate diagnosis and leave the species-level status and ecological interpretation uncertain.

Subject of Research: Micro-CT reconstruction and phylogenetic analysis of an indeterminate Upper Jurassic atoposaurid from Portugal

Article Title: New dwarf crocodylomorph from the Upper Jurassic of Portugal and the first neuroanatomical data for Atoposauridae

Article References: Puértolas-Pascual, E. (2025). New dwarf crocodylomorph from the Upper Jurassic of Portugal and the first neuroanatomical data for Atoposauridae. Fossil Record, 28(2), 321-346. https://doi.org/10.3897/fr.28.167846

Image Credits: AI Generated

DOI: 10.3897/fr.28.167846

Keywords: Atoposauridae, crocodylomorph, palaeoneurology, micro-CT, Lourinhã Formation, Upper Jurassic, Portugal, neurosensory reconstruction, phylogenetics, palaeontology, dwarf, Upper

Rhabdodontids were generally small- to medium-sized, probably habitually bipedal herbivores with stocky bodies, strong hind limbs, short forelimbs, long tails and comparatively large, triangular skulls that tapered toward pointed snouts. Their chewing apparatus included a keratinous beak at the front of the mouth and cheek teeth suited to shearing or slicing. In Zalmoxes, large jaw-adductor muscle chambers, robust jaws and a well-developed coronoid process were interpreted as indicators of high bite strength.

Other features, including the relatively narrow jaw tips of Zalmoxes and the enlarged teeth of Matheronodon, led researchers to propose selective feeding on tough or fibrous vegetation. These interpretations are supported by several lines of evidence, but no complete articulated skull has yet demonstrated the precise motions of the jaw and upper skull. The group’s taxonomic history began when Philippe Matheron named Rhabdodon priscum from material discovered in southern France in 1840s.

The original assemblage included a fragmentary left dentary and postcranial elements; the dentary, now the lectotype, was subsequently selected from the collection of the Palais Longchamp Museum. Austrian material from Muthmannsdorf became Iguanodon suessi in 1871 and Mochlodon suessi in 1881. Fossils found in Romania’s Hațeg Basin were studied extensively by Franz Nopcsa, who moved them repeatedly among Mochlodon, Rhabdodon and other groups.

A major 2003 revision separated the Romanian remains into the genus Zalmoxes and formally established the family Rhabdodontidae. The name Rhabdodon had briefly been displaced because it was already occupied by a snake, but the International Commission on Zoological Nomenclature conserved the dinosaur name in 1987 and amended the species name to Rhabdodon priscus. Research in the following decades expanded the roster from three genera to six.

Matheronodon provincialis was named in 2017 from a single right maxilla from the Aix-en-Provence Basin in southern France. Pareisactus evrostos, described in 2019, is known from a nearly complete left scapula in north-eastern Spain. Transylvanosaurus platycephalus, named in 2022, is represented by a partial skull containing the articulated basicranium and both frontals from Romania’s Hațeg Basin.

Its discovery is important because many late Maastrichtian rhabdodontid remains from Transylvania had previously been assigned to Zalmoxes without strong supporting evidence. Matheronodon and Pareisactus remain known only from their holotypes, while the completeness and taxonomic unity of the specimen assigned to Zalmoxes shqiperorum from Nălaț-Vad have also been questioned. These limitations mean the family’s true diversity could still be underestimated.

Most phylogenetic analyses place Rhabdodontidae near the base of Iguanodontia, a radiation that later included animals such as Iguanodon and hadrosaurs. The relationships within the family are less secure. Rhabdodon from France and Spain has usually been placed apart from a clade containing Mochlodon from Austria and Hungary and Zalmoxes from Romania, a pattern that has been interpreted as western and eastern European lineages.

Pareisactus was recovered as the sister taxon of Rhabdodon priscus in the single analysis that included it, whereas Matheronodon has not yet been placed in a phylogenetic analysis. Transylvanosaurus complicates the geographic division: morphological comparisons found similarities with Rhabdodon from France and differences from Zalmoxes, prompting the proposal that at least one major dispersal occurred between western and eastern parts of the archipelago. Because important taxa await revision, the review cautions against treating any single biogeographic scenario as settled.

The ancestry of the family extends further back than its European fossil record suggests. Rhabdodontids are securely known only from Upper Cretaceous rocks, but their position near the base of Iguanodontia implies a long ghost lineage in which earlier representatives left no confirmed fossils. A more inclusive group, Rhabdodontomorpha, has been proposed to include the unnamed “Vegagete ornithopod” from the Early Cretaceous of northern Spain.

That animal has alternately been placed within Rhabdodontidae, immediately outside it and as the closest relative of the family. Other proposed close relatives include Tenontosaurus from the western United States, Muttaburrasaurus from eastern Australia, Fostoria from eastern Australia and the recently described Iani from the western United States, although alternative placements have been proposed for several of them. Because derived rhabdodontids are known only from Europe, the review considers a European origin of the family likely while emphasizing that its deeper history remains uncertain.

The Sibişel Valley succession of the Hațeg Basin was deposited on a poorly channelised alluvial plain containing active channels, wetlands, floodplains and higher, drier ground. A taphonomic survey found rhabdodontid remains across those settings, including well-drained palaeoenvironments, demonstrating that the animals were not restricted to swamps or lakes. Some bone beds contain several Zalmoxes individuals of different sizes with similar taphonomic histories, and a Spanish locality attributed to the “Vegagete ornithopod” contains at least six individuals.

These associations are consistent with gregarious behavior, although they do not establish it as universal across the family. Analyses of teeth provide more specific, but taxon-dependent, evidence about diet. Stable-isotope measurements of Zalmoxes teeth from the Hațeg Basin indicate consumption mainly of C3 plants and were interpreted as showing no large-scale habitat partitioning between rhabdodontids and hadrosauroids from the same locality.

Dental microwear on Mochlodon vorosi from Hungary shows straight, parallel striations, consistent with orthal jaw movement, while its high tooth-formation rate indicates an abrasive diet. The microwear pattern further suggests a low-browsing herbivore feeding within roughly one metre of the ground on tough vegetation. Differences between M. vorosi and sympatric hadrosaurs indicate different feeding ecologies, while a contrasting pattern in the ankylosaur Hungarosaurus suggests niche partitioning between that animal and M. vorosi.

Differences in the proportions of the dentaries and dentition of Rhabdodon priscus, R. septimanicus and Matheronodon also support some dietary differentiation, although the extent of partitioning among rhabdodontid species remains uncertain. The disappearance of rhabdodontids was neither simultaneous nor geographically uniform. In the Ibero-Armorican realm, rhabdodontids and nodosaurids appear to have disappeared by the early late Maastrichtian, approximately 69 million years ago, as a titanosaur-, rhabdodontid- and nodosaurid-dominated fauna was replaced by one dominated by hadrosauroids and titanosaurs.

The arrival of hadrosauroids may have contributed to this turnover, but they could also have expanded into ecological niches left vacant if the earlier herbivores were already declining. A change in plant food is another possibility: browsing-associated pit-dominated microwear in European rhabdodontids and nodosaurids was followed by scratch-dominated microwear in hadrosauroids, potentially reflecting more open habitats and different vegetation. The Transylvanian realm showed greater faunal stability, with rhabdodontids surviving well into the late Maastrichtian and remaining among the last non-avian dinosaurs before the end-Cretaceous extinction.

The causes of these contrasting histories cannot yet be separated confidently. The review presents Rhabdodontidae as an unusually informative but unresolved branch of dinosaur evolution. Its European distribution links it to the biogeographic history of an island realm, while its changing classifications expose the difficulty of identifying taxa from jaws, teeth, shoulder bones and incomplete skulls.

Questions about movement and growth are equally open. Rhabdodontids are usually reconstructed as bipedal, but Rhabdodon has also been portrayed as quadrupedal, and recent comparisons suggest that some rhabdodontomorphs shifted from four-legged to two-legged posture during growth. Histological studies also indicate different growth patterns among taxa, including rapid growth in the “Vegagete ornithopod” and relatively slow growth in Zalmoxes.

More complete and articulated skeletons, revision of historical specimens, and complementary analyses such as biomechanical modeling, stable-isotope work, dental microwear and muscle reconstruction will be required to separate established observations from the many evolutionary and ecological interpretations that remain possible.

Subject of Research: Taxonomy, palaeoecology, biogeography and extinction of Late Cretaceous European rhabdodontid dinosaurs

Article Title: The Rhabdodontidae ( Dinosauria , Ornithischia ), an enigmatic dinosaur group endemic to the Late Cretaceous European Archipelago

Article References: Augustin, F. J., Ősi, A., & Csiki-Sava, Z. (2023). The Rhabdodontidae (Dinosauria, Ornithischia), an enigmatic dinosaur group endemic to the Late Cretaceous European Archipelago. Fossil Record, 26(2), 171-189. https://doi.org/10.3897/fr.26.108967

Image Credits: AI Generated

DOI: 10.3897/fr.26.108967

Keywords: Rhabdodontidae, ornithopod dinosaurs, Late Cretaceous, European archipelago, palaeontology, fossil taxonomy, dinosaur biogeography, herbivorous dinosaurs, dental microwear, Iguanodontia, Dinosauria, Ornithischia

Diaphanopterodea were members of the broader group Megasecopteromorpha, an assemblage of extinct insects that flourished during the Late Palaeozoic, roughly 300 million years ago. Compared with other lineages of this group, diaphanopterodeans are known from relatively few species and fossil specimens, which makes every new find valuable. What has long fascinated researchers about these insects is their ability to fold their wings backwards along the abdomen at rest, a capacity known as neoptery. This trait was once considered the ancestral condition for all winged insects, but most specialists now accept that it evolved convergently, appearing independently within Megasecopteromorpha and within the larger neopteran radiation. Over the roughly 75 million years of their evolutionary history, diaphanopterodeans also diversified into remarkably small forms with greatly reduced wing venation, a body plan that superficially recalls that of modern wasps and bees.

The new specimen, catalogued as YQZYW 15, was collected from a siltstone layer in the middle part of the Shanxi Formation at a locality called Shuiquan Gully, in the Duanjiabei District near the city of Yangquan. The Shanxi Formation is a sequence of deposits laid down under conditions of continental and oceanic interaction, consisting mainly of coal, mudstone, siltstone and sandstone. It conformably overlies the Taiyuan Formation and underlies the Xiashihezi Formation. The fossil-bearing layer is grey and packed with plant fossils, including the seed fern foliage Neuropteris ovata, several species of the tree fern Pecopteris, and the cordaitalean conifer relative Cordaites. Based on its lithological characters, this layer is assigned to the Asselian age of the Permian, the earliest stage of the Cisuralian epoch, dating the insect to approximately 299 to 293 million years ago. The upper part of the fossiliferous interval contains marine invertebrates such as brachiopods and gastropods, painting a picture of a humid, vegetated coastal environment where insects thrived among dense forests.

Only a single right forewing was preserved, split between a part and counterpart slab, with the distal portion missing. Even so, its preservation quality proved sufficient for detailed analysis. The preserved wing measures 15.4 millimeters in length and 5.5 millimeters in width, and its venation pattern carries a suite of diagnostic features: a dark area between the anterior wing margin and the radius, a subcostal vein that vanishes before reaching the radius, a forked cubitus posterior, and an exceptionally well-developed anal area bearing eight terminal branches. The researchers documented the fossil using high-resolution photography under both dry and ethanol immersion conditions, combining images from both sides of the slab to capture the maximum anatomical detail, and complemented the photographs with careful hand-drafted interpretive drawings made with a stereomicroscope equipped with a drawing tube.

Assigning the specimen to its correct position in the insect family tree required a broad comparative analysis of wing venation across all known members of the families Parelmoidae and Elmoidae, the two closest relatives of the new material. The key turned out to be a very short, oblique cross-vein in the region between the anterior and posterior cubital veins, a feature that places the specimen firmly within Diaphanopterodea while excluding affinity with the Sinodiaphidae. A long fusion of the anterior cubital vein with the combined radial and medial stem rules out the Diaphanopteridae, and the overall configuration of veins points squarely to the Parelmoidae. Affinity with the Elmoidae was also tested and rejected: elmoid insects have a narrow anal area with a simple anal vein, whereas the new specimen shows a broad anal fan with numerous long veins, a signature of the Parelmoidae.

Within the Parelmoidae, comparisons with individual genera further confirmed that the Chinese wing belongs to something new. In the genera Parelmoa, Pseudelmoa and Elmodiapha, known from the famous Early Permian localities of Elmo and Midco in Kansas and Oklahoma, and from Obora in the Czech Republic, the split between the anterior and posterior branches of the media lies well beyond the split of the radius, whereas the two splits occur at the same level in the Chinese fossil. The new species also differs from these genera and from Permuralia of Russia by its brief cross-vein connection between the radius posterior and media anterior, and by its forked cubitus posterior. Comparison with Permelmoa magnifica from the Lodève locality in France prompted the researchers to re-examine the French holotype using reflectance transformation imaging, a technique that captures how a fossil surface reflects light from dozens of directions and allows virtual relighting of the specimen.

That re-examination yielded a series of corrections to the earlier interpretation of Permelmoa magnifica. The original description reported three branches of the radius posterior, but the new analysis found four; the course of the anterior cubital vein was reinterpreted; and a structure previously identified as a basal portion of the posterior media was reassigned as a twin, shifted impression of the anterior cubitus, a preservation artifact documented in other material from Lodève. The authors also proposed an alternative homology for the medial vein system, suggesting that the media anterior may run fused with the radius for some distance rather than arising from a free medial stem. However the debate on the French species resolves, the Chinese fossil remains distinct from it in numerous respects, justifying the erection of a new genus and species.

Beyond the taxonomy, the good preservation of Sinoelmoa yangquanensis allowed the team to resolve a lingering uncertainty about the arrangement of the main veins near the wing base in Diaphanopterodea. In most members of the order, the space between the cubital stem and the combined radial-medial stem is extremely narrow, and the free distal portion of the anterior cubitus diverges right next to the point where the radius and media separate, making it nearly impossible to tell whether the entire cubital stem, or only its anterior branch, fused with the radial-medial stem. In the new specimen, an independent cubital stem is clearly visible, with a simple anterior cubitus running alongside the radial-medial stem for some distance before diverging abruptly. This observation overturns the assumption of an early common stem combining all three vein systems, and instead corroborates previous observations of a more or less brief connection between the anterior cubitus and the radial-medial stem, a pattern likely general to most diaphanopterodean families and probably present in the specialized families Martynoviidae and Asthenohymenidae as well.

The biogeographic implications of the find may prove just as important as its anatomical ones. Until now, the Parelmoidae were known only from localities in what are now the Czech Republic, the United States, France and Russia, all in the western and central parts of the Palaeozoic world. Sinoelmoa yangquanensis, being Asselian in age, constitutes the earliest occurrence of the family, and being situated along the eastern margin of the Palaeotethys on the North China Block, it is also the most oriental. Together, these two superlatives suggest that these rather infrequent insects enjoyed a far broader geographic distribution than the sparse fossil record had indicated, at least along the lower latitudes of the Northern Hemisphere, when the supercontinent Pangaea was still assembling and dense coal-forming forests stretched across the tropical belt.

The discovery also underscores how much remains to be learned from even a single wing. Because diaphanopterodeans are rare and their fossils often deformed or incomplete, paleontologists must rely on subtle details of venation, the branching patterns and cross-veins etched into chitin hundreds of millions of years ago, to reconstruct their evolutionary relationships. Sinoelmoa yangquanensis demonstrates that careful comparison of these features, supported by modern imaging techniques and re-examination of old museum specimens, can still overturn long-held assumptions about how these ancient insects were built. It is a reminder that the earliest experiments in wing folding, a capability that today defines the vast majority of insect species, were unfolding in parallel lineages across a Permian world whose full diversity is only beginning to come into view, one slab of siltstone at a time.

Subject of Research: Early Permian diaphanopterodean insects and the discovery of a new Parelmoidae species from China

Article Title: The first Permian Diaphanopterodea ( Insecta , Megasecopteromorpha ) from China

Article References: Yang, N., Cui, Y., Xu, Z., Xu, Y., Ren, D., & Béthoux, O. (2024). The first Permian Diaphanopterodea (Insecta, Megasecopteromorpha) from China. Fossil Record, 27(2), 247-258. https://doi.org/10.3897/fr.27.128892

Image Credits: AI Generated

DOI: 10.3897/fr.27.128892

Keywords: Diaphanopterodea, Parelmoidae, Sinoelmoa yangquanensis, Permian insects, Shanxi Formation, fossil insects, wing venation, palaeontology, China, North China Block, Cisuralian, Megasecopteromorpha

The choice of theme for the anniversary volume is no accident. The evolution of early land vertebrates is one of the main research areas at the Museum für Naturkunde Berlin, where several research groups focus on how finned aquatic ancestors gave rise to four-limbed animals capable of life on land. This transformation, which unfolded over tens of millions of years during the Devonian and Carboniferous periods, involved profound anatomical and physiological changes: limbs with digits replacing fins, lungs and modified circulatory systems supplementing or replacing gill-based respiration, restructured skulls and necks suited to feeding in air rather than water, and sensory systems retooled for a world of light, sound and gravity fundamentally different from the aquatic realm.

Understanding this transition requires fossils that capture animals at intermediate stages, and it is here that the museum’s active fieldwork programme plays a crucial role. At the Bromacker site in Thuringia, an intensive excavation and research campaign is being carried out in close collaboration with Jena University, the Stiftung Schloss Friedenstein in Gotha and the UNESCO Geopark Drei Gleichen. The Bromacker has long been celebrated for its early Permian terrestrial vertebrate fossils, offering a window onto ecosystems that existed shortly after vertebrates first established themselves on land. Such sites provide the raw material for testing hypotheses about how early tetrapods walked, breathed, fed and diversified as they moved into terrestrial habitats.

The anniversary volume itself was curated by three editors, who assembled what the museum describes as a very interesting and diverse cross-section of modern research articles on early tetrapods. Special issues of this kind serve an important function in palaeontology, gathering scattered strands of research into a single collection that allows readers to see the state of a field at a glance. For a journal marking twenty-five years of publication, the theme also connects the anniversary to the institution’s scientific identity: the Museum für Naturkunde Berlin is not merely a publisher of research on early tetrapods but an active producer of it.

The journal’s own history mirrors broader changes in scientific publishing. In its early years, a large share of submitted manuscripts came from authors affiliated with the Museum für Naturkunde Berlin itself. Today, most submissions arrive from abroad and from researchers with no connection to the museum, a shift that signals the journal’s successful transformation into a genuinely international venue. That visibility is reflected quantitatively as well: a place in the top quartile of palaeontological journals places Fossil Record among the most influential outlets in a competitive field that spans everything from micropalaeontology to vertebrate evolution and deep-time biodiversity studies.

A pivotal moment came in 2014, when, in consultation with its stakeholders, the journal was converted into an open access publication. The move was a deliberate statement by the Museum für Naturkunde Berlin about the open availability of research results, the idea that publicly funded science should be freely readable by anyone, anywhere, without subscription barriers. The subsequent success of the journal, the museum argues, has vindicated that decision. Open access has become the dominant direction in scientific publishing globally, driven by funder mandates and by the recognition that paywalls limit both the reach of research and its ability to inform education, policy and public understanding of science.

What makes Fossil Record unusual among open access journals is its funding model. Most open access journals charge authors an article processing charge, a fee that can run to thousands of dollars per paper and that critics argue creates inequities, favouring well-funded institutions in wealthy countries and potentially excluding researchers from lower-income settings. Fossil Record requests no such charges from authors. Instead, the costs of publication have been covered by the Museum für Naturkunde Berlin itself, an arrangement that keeps the journal free to read and free to publish in, and that the museum presents as part of its broader commitment to equitable access to scientific knowledge.

The anniversary also offers an occasion to reflect on the mechanics of a successful scientific journal. In his welcoming address marking the occasion, the museum’s Director General credited the editorial board of Fossil Record and the museum’s publication office for their tireless efforts to improve the journal’s quality and visibility, and highlighted the deep and trusting cooperation between the museum’s directorate, its publication management team and the journal’s editors. This team approach, he argued, has contributed significantly to the journal’s success, a reminder that behind every impact factor stands a network of editors, reviewers, copy editors and production staff whose work determines whether a journal earns the trust of its community.

For readers of the special volume, the scientific payoff lies in the content itself. Research on the fish-to-tetrapod transition sits at the intersection of several disciplines: comparative anatomy, which reconstructs how skeletal structures changed; palaeohistology, which examines fossilized bone microstructure to infer growth and physiology; ichnology, the study of trace fossils such as footprints that record how early land animals actually moved; and geochemical and sedimentological analyses that reconstruct the ancient environments in which these animals lived. Together, such approaches have reshaped scientific understanding of the transition, painting a picture of a gradual, experiment-filled process in which many early tetrapods remained tied to aquatic habitats even as they acquired increasingly terrestrial features.

As Fossil Record enters its next quarter-century, the museum’s leadership has expressed pride in the journal and optimism about its future, noting that it stands alongside two other scientific journals published by the Museum für Naturkunde Berlin. For the palaeontological community, the anniversary volume on early tetrapods is both a celebration and a working resource: a collection of current research on one of evolution’s great transitions, published in a journal that has made openness, international participation and institutional support the foundations of its identity. Twenty-five years after its foundation, Fossil Record has come a long way, and its anniversary theme ensures that the celebration is anchored in the science the museum knows best.

Subject of Research: Anniversary of the palaeontological journal Fossil Record and research on the fish-to-tetrapod transition

Article Title: Welcoming address of the Director General

Article References: Vogel, J. (2024). Welcoming address of the Director General. Fossil Record, 27(3), 289-289. https://doi.org/10.3897/fr.27.142092

Image Credits: AI Generated

DOI: 10.3897/fr.27.142092

Keywords: Fossil Record, Museum für Naturkunde Berlin, tetrapods, fish-to-tetrapod transition, open access, palaeontology, Bromacker, Thuringia, early land vertebrates, scientific publishing, impact factor, anniversary volume

The road to this milestone was far from smooth. The early editors, Professor Gloria Arratia and Dr Dieter Korn, imposed exacting standards on article quality and impact at a time when the journal was still struggling to establish itself, and their persistence ultimately carried ‘Fossil Record’ into the Science Citation Index Expanded in 2014. The journal has maintained a tradition of publishing exclusively in English, releasing two volumes every year and subjecting every submission to the scrutiny of at least two international reviewers. More recently, it has embraced a fully open access model, a transformation supported by the museum’s Coordination Office for Scientific Publishing, which acts as a key driver of the institution’s Open Access strategy. The museum itself, through its Directorate General, has generously covered the author page charges, ensuring that financial barriers do not prevent researchers from sharing their findings with the global scientific community.

The choice of topic for the anniversary volume is no accident. The fish-to-tetrapod transition has a long and illustrious tradition at the Museum für Naturkunde, stretching back to Walter Gross (1903–1974), the eminent palaeoichthyologist and histologist who discovered and first described the Devonian tetrapod-like fish Panderichthys rhombolepis. The holotype of this pivotal species, a creature perched on the evolutionary branch leading from lobe-finned fishes toward the first four-legged land animals, is still kept at the museum. Hans-Peter Schultze and his working group continued Gross’s work and expanded its scope, publishing important new findings on Elpistostege, a relative of Panderichthys that sits even closer to tetrapods on the tree of life, and investigating the phylogenetic status of tetrapods as a monophyletic group as well as the environmental conditions that accompanied the transition from water to land.

That institutional tradition also owes much to a remarkable series of visiting researchers. Michel Laurin worked at the museum from 1997 to 1998, and Rainer Schoch from 2001 to 2002, both of whom went on to become distinguished figures in early tetrapod research. Today the baton is carried by the research groups led by Nadia Fröbisch and Florian Witzmann, whose primary focus is on temnospondyl amphibians, an extraordinarily successful and long-lived group of ancient amphibians that flourished for well over 100 million years. The special issue that emerges from this lineage is both a celebration of a journal and a showcase of how a single research institution can shape a field across generations.

Why does vertebrate terrestrialization continue to fascinate scientists and the public alike? Following the conquest of land, vertebrates evolved a remarkable diversity of body proportions and a wide array of feeding, locomotory and sensory adaptations, laying the foundations for every terrestrial ecosystem that exists today. Early tetrapods illuminate the rise of those ecosystems and reveal the deep roots of much of modern terrestrial vertebrate diversity, from amphibians and reptiles to birds and mammals. And because the emergence of four-limbed, air-breathing animals from aquatic ancestors is one of the major evolutionary transitions in the history of animal life, every new discovery in this field is, in a very real sense, a discovery about our own remote ancestry. It is this combination of scientific depth and visceral human relevance that makes early tetrapod research so compelling.

The special volume opens with a welcoming address by Professor Johannes Vogel, Director General of the Museum für Naturkunde, followed by a personal account from Hans-Peter Schultze of the journal’s founding in 1998 and the considerable difficulties it faced in its early years. The scientific core consists of eight original research articles written by 18 international authors, ranging from established leaders to young researchers at the start of their careers. Together, the papers span the palaeoecology of the fish-tetrapod transition, the morphology and phylogeny of stem tetrapods, the evolutionary history of temnospondyls, the convergent simplification of the tetrapod skull, and the biomechanics of skull construction in semi-aquatic and fully terrestrial tetrapods.

The first research article tackles a question that has long divided the field: where did tetrapods actually originate? By analogy with modern amphibians, most researchers had assumed that early tetrapods lived in freshwater environments, had evolved from fish-like ancestors there, and were unable to tolerate brackish or marine conditions. Michel Laurin challenges this orthodoxy. Building on a vast compendium of data and a sweeping literature survey, and expanding on his earlier 2010 study with Rodrigo Soler-Gijón, Laurin follows multiple independent lines of evidence to show that many early tetrapods were euryhaline, meaning they could tolerate a wide range of salinities, and lived in brackish waters or even fully marine settings. His striking conclusion is that tetrapods originated in marine environments, overturning a century of assumptions drawn from the biology of today’s frogs and salamanders.

The second article addresses one of palaeontology’s most notorious mysteries: Romer’s Gap. The first body fossils of limbed stem-tetrapods appear in the Late Devonian, yet during the first 15 million years of the subsequent Carboniferous Period, the Tournaisian and parts of the Viséan, tetrapod remains are exceedingly rare worldwide, a puzzling hiatus that gives the interval its name. In recent years, new finds from Scotland and Canada have begun to close this gap, and Tim Smithson and Marcello Ruta, together with the late Jenny Clack, redescribe one of these newly discovered Tournaisian tetrapods, Ossirarus kierani from Scotland. The animal displays a striking mosaic of primitive and derived characters, and the authors’ phylogenetic analyses strengthen the hypothesis that the morphological and taxonomic diversity of early tetrapods in the lowermost Carboniferous was far greater than previously assumed.

Several papers in the volume probe the astonishing experimentalism of early tetrapod evolution. Kim Kean, Marylène Danto, Celeste Pérez-Ben and Nadia Fröbisch survey the multiple groups of tetrapods that independently reduced and lost skull roof bones, attaining a simpler cranial architecture than that of tetrapodomorph fishes and various Devonian and later Palaeozoic relatives. Intriguingly, the loss of individual bones proved highly variable and could not be correlated with any particular lifestyle or body size, suggesting complex morphogenetic patterns that remain poorly understood. Ralf Werneburg and Florian Witzmann then turn to the eryopids, a diverse group of Permo-Carboniferous temnospondyls that had shifted from a strictly aquatic existence to a more amphibious mode of life. Their detailed redescription of three enigmatic Middle Permian taxa from Russia, Clamorosaurus borealis, C. nocturnus and Syndyodosuchus, combined with a comprehensive phylogenetic analysis, finds no support for the earlier view that these Russian eryopids were terrestrial, and instead argues that a semi-aquatic lifestyle is more probable.

The remaining contributions extend this story across the Triassic world and into the mechanics of the skull itself. Raphael Moreno, Sanjukta Chakravorti, Samuel Cooper and Rainer Schoch document a surprisingly rich diversity of temnospondyls from the partially marine Grabfeld Formation of southwestern Germany, straddling the Ladinian-Carnian boundary, including the oldest known metoposaurid and evidence that many members of the group were euryhaline despite arid sabkha and playa conditions. Rainer Schoch, Florian Witzmann, Raphael Moreno, Ralf Werneburg and Eudald Mujal describe for the first time the ontogeny of the largest known temnospondyl, the giant capitosaurian Mastodonsaurus giganteus from the Middle Triassic of Germany, using skulls ranging from just 12–15 millimetres to a colossal 1200 millimetres; unlike Palaeozoic forms, which had salamander-like larval phases, Mastodonsaurus attained its adult morphology early in development, revealing a major shift in developmental mode. Pummy Roy, Sanjukta Chakravorti and Dhurjati Prasad Sengupta newly document the anatomy of the giant Indian capitosaur Cherninia denwai, an apex predator from the Middle Triassic Denwa Formation, including postcranial bones described for the first time. Finally, Ingmar Werneburg offers a new biomechanical hypothesis for the evolution of cranial openings such as temporal fenestrae and palatal vacuities, showing that their formation or closure correlates tightly with bite force exerted by the jaw adductors, with the presence of cranial weapons such as horns and frills, and even with stresses induced by the neck musculature. Together, these studies honour a quarter century of ‘Fossil Record’ while charting the future of research into the greatest migration in vertebrate history.

Subject of Research: The 25th anniversary of the journal Fossil Record and a special issue on the fish-to-tetrapod transition and early tetrapod evolution

Article Title: Editorial: 25 years of ‘Fossil Record, an International Journal of Palaeontology’

Article References: Witzmann, F., Ruta, M., Fröbisch, N., Paß, S., & Herrmann, E. (2024). Editorial: 25 years of ‘Fossil Record, an International Journal of Palaeontology’. Fossil Record, 27(3), 291-293. https://doi.org/10.3897/fr.27.143987

Image Credits: AI Generated

DOI: 10.3897/fr.27.143987

Keywords: Fossil Record, palaeontology, tetrapods, fish-to-tetrapod transition, temnospondyls, Museum für Naturkunde, Romer's Gap, Devonian, Carboniferous, Triassic, skull biomechanics, open access

The journal’s origins read like a who’s who of nineteenth-century palaeontology. Founded as a series of mostly monographs, the Schweizerische Paläontologische Abhandlungen carried the work of pioneering researchers such as Oskar Heer, Ludwig Rütimeyer, Paul de Loriol, and many others whose names remain familiar to anyone who has studied the history of the discipline. A considerable backstock of these printed manuscripts, including many of the old monographs, is still available for sale today, and some of the earliest volumes can be downloaded through the Biodiversity Heritage Library. Few scientific journals can trace an unbroken publishing tradition across three centuries of geological and biological thought.

Institutional stewardship of the series changed hands in 1940, when the Schweizerische Naturforschende Gesellschaft, now known as the Swiss Academy of Sciences SCNAT, formally took over publishing responsibility from the foundation that had originally issued the monographs. The foundation’s funds were transferred to the society, which committed to managing them in a dedicated stock reserved solely for the publication of the series. At the same time, a commission was established to oversee the journal, and that body, today known as the Commission for the Swiss Journal of Palaeontology, has remained in charge of publication ever since.

For decades, from the 1930s until 2010, the monograph series appeared at irregular intervals through the Basel-based scientific publisher Birkhäuser, which was itself acquired by Springer in 1985. A decisive modernisation arrived in 2011, when the series was renamed the Swiss Journal of Palaeontology and established as a peer-reviewed scientific journal. From volume 130 in 2011 until 2019, the journal was published with Springer as a hybrid journal that was still printed on paper, and from 2020 onward it became an online-only, fully open access publication under the SpringerOpen imprint. Since 2025, the journal has been officially affiliated with the Swiss Geological Society, into which the Swiss Palaeontological Society was integrated as a specialist section back in 2015.

The shift to full open access in 2020 was not merely a fashion statement. It was triggered by a policy decision of the Swiss National Science Foundation, which declared that it would no longer support publication in traditional subscription-model journals, including hybrid open access journals. The funder required grantees to make the results of its projects available in open access journals or databases, and offered grants to cover open access publishing costs. That policy pushed the journal fully into the open access era, and the consequences have been striking: freed from the considerable expenses of printing and the associated workload on the chief editor, the journal has grown steadily, publishing more than 70 articles in 2025 alone, with an annual target of at least 30 to 40 articles going forward.

With its contract with SpringerOpen expiring at the end of 2025, the Commission for the Swiss Journal of Palaeontology and the Swiss Geological Society began searching for a publishing partner whose workflows would be more closely tailored to the journal’s needs. Negotiations with Pensoft Publishers started in July 2025, and contracts were signed in September 2025. The Swiss Journal of Geosciences, which is also affiliated with the Swiss Geological Society, made the same migration from SpringerOpen. Since October 2025, the new journal website has been live, and to commemorate the change the journal unveiled a new logo featuring the iconic ammonite genus Macrocephalites paired with a Swiss cross, a visual nod to both the journal’s scientific subject matter and its national heritage.

The move also brings a new financial model designed to widen access to publication for researchers who lack dedicated funding. Authors who do have full funding for open access publication, for example through a Swiss National Science Foundation project, are asked to pay the standard Article Processing Charge of 1,500 euros, which covers publication of up to 26 pages in the final print-ready PDF, with additional pages costing 30 euros each. Crucially, part of that fee flows directly back into the journal’s equity mechanisms rather than into the publisher’s margins, funding waivers and discounts for authors without adequate funding. Members of the Swiss Geological Society will receive at least a 25 percent discount, or a full waiver if they lack funding and serve as corresponding or first author. Requests for waivers or discounts must be made during manuscript submission, and the journal is explicit that such requests have no bearing on the outcome of peer review.

The editorial team has also refreshed the journal’s focus and scope to reflect the breadth of modern palaeontology. The journal welcomes original research and review articles across the full spectrum of the field, from alpha taxonomy and systematics to palaeobiology, palaeoecology, palaeobiodiversity, biostratigraphy, and conservation palaeontology. Notably, it explicitly embraces studies employing cutting-edge methods such as CT and synchrotron scanning, geochemical analyses, and complex phylogenetic analyses, alongside work that documents high-quality palaeontological data in regional contexts, particularly Switzerland and its neighbouring countries. Topical Collections will continue to be published, and articles within them remain eligible for Swiss National Science Foundation financing, whereas articles in Special Issues are no longer covered by the funder.

Bibliometric indicators suggest the journal’s visibility has never been stronger. Since 2017 it has held a Clarivate Impact Factor, and its current metrics place it firmly in the first quartile of palaeontology journals: a Scopus CiteScore of 4.8 and a Clarivate Web of Science two-year Impact Factor of 2.2, both for 2024. That first-quartile standing matters enormously to researchers, since many funders and institutions require publication in top-ranked journals. The appetite for the journal’s content is also reflected in its download statistics, with 188,139 full-text downloads recorded in 2024. Pensoft additionally offers a print-on-demand service for readers who still want physical copies, as well as professional language editing and tailored press release campaigns to amplify the reach of published research.

Behind the scenes, the journal has invested in professional editorial infrastructure. A part-time Chief Editor position was created in 2014 to help the journal run more efficiently and compete with journals published by profit-oriented publishers, a role currently held by Dr. Daniel Marty. The editorial board has been strengthened in recent years and is actively seeking new subject editors, with a particular push to increase the number of women in palaeontology serving as editors. The commission also continues to nurture the next generation through the Paleoprize, awarded since 2006 to an early-career researcher for the best talk at the annual palaeontology session of the Swiss Geoscience Meeting, and through the Prize Amanz Gressly, which honours major contributions to the field. With the 145th volume now launching under Pensoft, the editorial team is looking to the Swiss palaeontological community, from established professors to students, to submit manuscripts, review papers, and help steer a journal that has now survived long enough to see its own fossils of publishing history. For a publication born in the age of hand-copied monographs, the open access future looks remarkably bright.

Subject of Research: The migration of the Swiss Journal of Palaeontology to Pensoft Publishers and its publishing history

Article Title: Editorial – Swiss Journal of Palaeontology migrates to Pensoft Publishers

Article References: Marty, D., Cavin, L., Daley, A. C., Drage, H. B., Hautmann, M., Joyce, W., & Klug, C. (2026). Editorial – Swiss Journal of Palaeontology migrates to Pensoft Publishers. Swiss Journal of Palaeontology, 145, 1-16. https://doi.org/10.3897/sjp.145.181236

Image Credits: AI Generated

DOI: 10.3897/sjp.145.181236

Keywords: Swiss Journal of Palaeontology, Pensoft Publishers, open access, palaeontology, scientific publishing, Swiss Geological Society, Swiss National Science Foundation, ammonite, peer review, journal migration, Swiss Academy of Sciences, article processing charge

The research team, working with material housed in the palaeontological collections of the National Museum in Prague, abandoned the traditional route of hunting for discrete anatomical characters, because there simply are none to find. The fossils preserve only the general vaulted outline of the cephalon, a raised longitudinal region, and a vague indication of the eyes; a single Zonozoe specimen shows what may be glabellar furrows, and Zonoscutum preserves similar structures in a different position. Crucially, all of the diagnostic features of the groups these fossils have been linked to, including the aglaspidids and their relatives within the clade Vicissicaudata, are post-cephalic, meaning they lie in body regions that were never preserved. Standard phylogenetic analysis, which depends on a matrix of observable traits, has therefore been effectively impossible. Earlier workers, including a major 2013 analysis of Vicissicaudata and a 2022 revision of the material, had concluded that the most anyone could honestly say was that the fossils belonged somewhere within the broad clade Artiopoda, the great assembly of extinct arthropods that includes trilobites and their kin.

The new study took a different path: instead of asking what features the fossils have, it asked what shape they are. The researchers compiled cephalic outlines from thirty-three early Palaeozoic arthropod species, spanning nine euchelicerates, six aglaspidids, three cheloniellids, two nektaspids, and a selection of other artiopodans, alongside Zonozoe and Zonoscutum themselves. Trilobites were deliberately excluded, a decision grounded in three practical reasons: Ordovician trilobite cephalic morphology is so extraordinarily diverse that it would have swamped the signal with noise, Zonozoe and Zonoscutum have never seriously been considered trilobite relatives, and the position of the eyes and glabella in the two enigmatic genera differs markedly from any contemporaneous trilobite. Each outline was traced as a black silhouette and converted into a mathematical description using elliptical Fourier analysis, a technique that decomposes a closed shape into a series of harmonic coefficients, capturing its geometry in a form that computers can compare objectively.

The mathematics behind the approach is elegant in its simplicity. Fifteen harmonics were retained, sufficient to capture 99.9 percent of the harmonic power in the dataset, meaning that nearly all of the meaningful shape information was preserved in the analysis. These coefficients were then fed into two complementary statistical frameworks. A principal component analysis compressed the high-dimensional shape data into a visual morphospace, where similar shapes cluster together and dissimilar ones drift apart. A linear discriminant analysis, trained on the known group memberships, tested how well the major groupings, euchelicerates, non-vicissicaudatan artiopodans, and vicissicaudatans, could be told apart on outline shape alone. The first two principal components alone explained 87.1 percent of the variation in the dataset, with PC1 accounting for 67.4 percent and PC2 for 19.7 percent, an unusually clean separation for fossil material this fragmentary.

The results were striking. In the principal component space, Zonozoe plotted squarely within the vicissicaudatan morphospace, nestled between the cheloniellid Neostrabops martini and the aglaspidid Aglaspis barrandei. Zonoscutum landed nearby, close to the cheloniellids Triopus and Drabovaspis complexa and the artiopodan Naraoia, in the lower region of the vicissicaudatan area. Both taxa fell far from the euchelicerate cluster, which occupied its own distinct corner of the morphospace. The discriminant analysis reinforced the pattern: euchelicerates were cleanly separated from all other groups, achieving 77.8 percent classification accuracy in leave-one-out cross-validation, while Zonozoe and Zonoscutum plotted at the edge of the artiopodan space, decisively outside the euchelicerate region. In plain terms, the shapes of these mysterious head shields look like vicissicaudatan artiopodans, and they emphatically do not look like the horseshoe crab relatives that some nineteenth-century workers once imagined.

This matters because the two genera have been dragged through nearly every possible interpretation since Barrande first described Zonozoe as a large ostracod carapace. Novák, in an unpublished 1887 manuscript, considered it a merostomate close to the synziphosurines. Chlupáč assigned it to Aglaspidida in 1963, an assignment he himself flagged as uncertain, and the same tentative label was later applied to Zonoscutum. Part of the confusion stemmed from the aglaspidids’ own turbulent taxonomic history: during the twentieth century they were shuffled between Xiphosura, Merostomata, and positions as sister group to the chelicerates, before modern phylogenies anchored them firmly within Vicissicaudata, a branch of Artiopoda. For much of that period, Aglaspidida functioned as something of a wastebasket taxon, a destination for any Ordovician arthropod too incomplete to place elsewhere, and Zonozoe and Zonoscutum, with their aglaspid-like head shields and their occurrence in the same palaeogeographic region as known aglaspidids, were natural candidates for that fate.

The authors are careful about the limits of their method, and that caution is itself instructive. Both Zonozoe and Zonoscutum plotted closer to cheloniellids than to aglaspidids in the two-dimensional outline space, but the team argues this is likely an artefact of compression: Zonoscutum has a highly vaulted cephalon and cheloniellids extremely flattened ones, and flattening three-dimensional shapes into two-dimensional outlines distorts exactly such extremes. Three-dimensional volume data would address the problem, but such data are difficult to obtain for fossils scattered across collections on multiple continents, and are themselves affected by flattening during fossilisation. The researchers therefore decline to overturn the 2022 conclusion that rejected a close relationship with the coeval and sympatric cheloniellid Triopus. What the analysis does firmly support is the negative result: an euchelicerate affinity is effectively excluded, and the most conservative classification of both genera within Artiopoda gains quantitative backing, with a more specific affinity to Vicissicaudata now considerably strengthened.

There is even a bonus finding buried in the morphospace. The proximity of Zonozoe to Neostrabops martini, a Late Cambrian form whose own classification has long rested on limited evidence, prompted the authors to suggest that Neostrabops itself may deserve re-examination, potentially toward Aglaspidida or, more parsimoniously, toward Xenopoda. Meanwhile, the close placement of Zonozoe beside Aglaspis barrandei is consistent with older qualitative observations, such as the position of the eyes and glabellar furrows behind them, traits that are not strongly diagnostic on their own but now align with an independent line of quantitative evidence. Neither conclusion is presented as definitive, but together they show how a method designed to squeeze information from unpromising material can generate genuinely new hypotheses about specimens that formal phylogenetics cannot touch.

The broader significance of the study extends well beyond two obscure Czech fossils. Mould-preserved specimens, which rarely retain fine anatomical detail, are routinely excluded from evolutionary and palaeoecological analyses precisely because the discrete characters needed for phylogenetic matrices are absent. Outline-based morphometrics offers a reproducible, quantitative alternative: less precise than a full phylogenetic analysis, but capable of admitting specimens that would otherwise sit forever in the too-difficult drawer. In this case, the technique has provided evidence for the presence of non-cheloniellid vicissicaudatans in the Letná Formation based on material that traditional qualitative methods would have overlooked entirely. A 150-year-old puzzle has not been solved with a new specimen or a spectacular discovery, but with a ruler’s worth of geometry applied to the outlines of what little remains, and that may prove to be the study’s most enduring legacy: a demonstration that even the most fragmentary fossils in the world’s museum drawers still have stories their shapes can tell.

Subject of Research: Morphometric reclassification of the enigmatic Ordovician arthropod fossils Zonozoe drabowiensis and Zonoscutum solum from the Czech Republic

Article Title: A morphometric approach to the taxonomic dilemma of Zonozoe drabowiensis Barrande, 1872 and Zonoscutum solum Chlupáč, 1999 (Upper Ordovician, Czech Republic)

Article References: Lustri, L., Laibl, L., Collantes, L., Bruthansová, J., Nohejlová, M., Liu, Y., & Pates, S. (2026). A morphometric approach to the taxonomic dilemma of Zonozoe drabowiensis Barrande, 1872 and Zonoscutum solum Chlupáč, 1999 (Upper Ordovician, Czech Republic). Swiss Journal of Palaeontology, 145, 145-155. https://doi.org/10.3897/sjp.145.179154

Image Credits: AI Generated

DOI: 10.3897/sjp.145.179154

Keywords: palaeontology, Zonozoe drabowiensis, Zonoscutum solum, Ordovician, arthropods, morphometrics, elliptical Fourier analysis, Vicissicaudata, Artiopoda, Aglaspidida, Czech Republic, taxonomy