PALEONTOLOGY NEWS

ABSTRACT

Dimetrodon is an early non-mammalian synapsid from the early Permian of Europe and North America best known for its elongated neural spines, which in life formed an interconnected sail, and an early occurrence of heterodonty in the fossil record. Previous literature has identified multiple pathologies in the genus, including fractured and healed neural spines and fractured and calloused limb bone midshafts, but no cranial pathologies have been described. We describe the first occurrence of cranial pathology in the genus in a specimen of Dimetrodon limbatus (AMNH FARB 4081) and hypothesize its causation. The pathology is a lesion on the anterior lateral surface of the right dentary directly ventral to the largest caniniform tooth that exhibits a filigree texture and margins of raised cortical surface anteriorly, posteriorly, and ventrally. The absence of a dorsal margin, other abscesses or puncture marks on the specimen characteristic of inter- or intraspecific combat, and the lesion’s location directly ventral to the upper caniniform tooth suggest that the lesion is the result of an accidental self-caused injury, perhaps during prey processing or hunting, in which the upper caniniform punctured the dentary.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2683596

ABSTRACT

Troodon formosus (T. formosus) is a theropod dinosaur from the Late Cretaceous of North America. T. formosus, like many theropods, are speculated to have used their forelimbs to hunt, and the complexity of their preserved egg clutches suggests T. formosus may have also used its forelimbs to move its eggs. Understanding the morphology and range of movement of T. formosus’s forelimb could help shed light onto these hypotheses. However, no complete forelimb material has yet been found for T. formosus, and a 3D reconstruction and range of motion (ROM) estimate has not been attempted. This study aims to address this gap by leveraging digital modelling technology to create the first forelimb reconstruction and ROM for T. formosus. Surface scans from multiple T. formosus fossils housed in the Museum of the Rockies (Bozeman, Montana) were digitally combined to reconstruct a nearly complete forelimb. Digital articulations based on this assembled model were compared with physical ROM using 3D printed copies. Results show higher ranges of flexion than extension in T. formosus’s joints, consistent with closely related species. However, T. formosus shows higher manual extension than close relatives. The humerus also shows anatomy convergent with more basal theropod species. These differences may imply a divergent morphology and function of the manus, as well as a deviation from avian ancestor forelimb morphology. ROM results cannot confirm whether T. formosus was able to grasp objects single-handed, but two-handed apprehension of objects, including eggs, remains feasible.

LINK(S)

https://peerj.com/articles/20987/

https://peerj.com/articles/20987.pdf

ABSTRACT

In this study, we report a partial skeleton of a small (ca. 7 m) sauropod dinosaur from the ?upper Lower Jurassic (Pliensbachian) to Bajocian strata of the Kaladongar Formation (Khadir Uplift), Kachchh Basin, India. The partial skeleton is described and established as the holotype of a new taxon, Ceratocaudia antiqua gen. et sp. nov., diagnosed by a notch on the cervical postzygapophysis, a horn-like crest on the anterior caudal neural spine, progressive shift from platycoelous to procoelous articular facets in the posterior caudal vertebrae, anterior chevron with split articular facets (local autapomorphy), a deeply concave (notched) anterior surface of the distal tibia, and a well-developed anteromedial crest and subtriangular distal epiphyses in the fibula (local autapomorphies). Additional fragmentary remains from the same strata at a nearby locality are referred to the new taxon. Phylogenetic analyses best support the recovery of the new taxon as an early-branching, non-titanosauriform macronarian. The long bone histology and non-traumatic, non-contagious pathology indicate senescence in the holotype. The possibility of dwarfism in C. antiqua, based on size and ontogenetic stage of the holotype, is discussed. A hypothetical caudal musculoskeletal reconstruction of C. antiqua, generated using retrodeformed and reconstructed elements of the holotype, is used to determine tentative functional morphological implications, including the use of the tail as a mild deterrent to predators. Time-calibrated phylogeny of macronarian taxa suggests a pre-Bajocian global distribution, supporting recent hypotheses on neosauropod paleobiogeography. Ceratocaudia antiqua is the earliest diagnosable macronarian neosauropod from India and represents one of its earliest global occurrences.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2677749

ABSTRACT

Liopleurodon ferox is a macropredatory pliosaurid plesiosaur from the Callovian (Middle Jurassic) of Europe. Several near-complete skeletons are known from the Peterborough Member of the Oxford Clay Formation of eastern England and approximately equivalent strata in north France. Disparate total lengths between 5.7 and 25 m have been reported for L. ferox, influencing paleoecological interpretations and length estimates for large pliosaurs. An updated model of Liopleurodon proportions and measurements is presented here, reconstructed from a near-complete skull and two well-preserved specimens with extensive postcranial remains. The skull comprises a larger proportion of the total skeletal length (24%) than a previously reported skull:body ratio of 1:5, and greater than the skull:body ratio of sympatric pliosaurs, indicating an ability to capture relatively larger prey. Intervertebral spacing (set at 10% based on other well-preserved plesiosaurians) was included in the final length determinations. By isometrically scaling a dataset of 37 specimens attributed to L. ferox, a total length range of 2.46–8.09 m is calculated. Liopleurodon is the largest aquatic tetrapod and apex predator of the Oxford Clay Formation paleoecosystem. Applying the new model to a range of indeterminate Oxford Clay pliosaurids as well as some Late Jurassic taxa, pliosaurs are calculated to reach total lengths up to 12.2 m, evolving gigantism by the Middle Jurassic and maintaining their position as apex predators for ∼80 my until they were superseded by mosasaurs in the late Turonian of the Upper Cretaceous.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2691149

https://www.tandfonline.com/doi/epub/10.1080/02724634.2026.2691149?needAccess=true

ABSTRACT

Resin production is a major innovation in land plants, signaling the evolution of specialized secretory systems, complex terpenoid biosynthesis, and defensive and wound-sealing functions. Yet its origin remains poorly constrained because fossilized resin (amber) is exceedingly rare in Paleozoic deposits, with the earliest widely accepted amber record from the Late Carboniferous. Here we report the earliest known amber from the Middle Devonian of China (~385 million years old), extending the geological record of amber by ~65 million years. Fourier transform infrared spectroscopy and gas chromatography–triple quadrupole mass spectrometry reveal chemical signatures comparable to conifer-type amber. These data indicate that some Middle Devonian vascular plants—most plausibly progymnosperms or arborescent lycopsids—had already evolved biosynthetic capacity consistent with terpene synthase. The early emergence of resin production may have promoted the ecological success of Devonian-Carboniferous terrestrial floras by enhancing protection and wound sealing.

LINK(S)

https://www.science.org/doi/10.1126/sciadv.aeh1266

ABSTRACT

Enchodus is a diverse and widespread genus of teleost fish known from the Late Cretaceous. Many North American species of Enchodus were erected based on isolated remains, including Enchodus dirus Leidy, 1857, which is named for a fragmentary dentary. We redescribe this holotype and find it to be nondiagnostic, lacking any defining characters to separate it from other species of Enchodus. A complete skull from the Niobrara Chalk, which was previously referred to E. dirus, is designated as the holotype of a new taxon, Enchodus machairus sp. nov. Enchodus machairus has a unique character suite, including: sigmoidal palatine teeth lacking postapical barbs, palatine teeth with a symmetrical cross-section and a single cutting edge, no marginal row of teeth on the mandible, no ornamentation on the mandible, and a rostrodermethmoid that is wider than long with lateral wings. The dentary teeth of the holotype of E. machairus lack prominent posterior ridges, unlike the holotype of E. dirus, and the two specimens are stratigraphically separated by 10 million years. Previous specimens referred to E. dirus are reviewed, and two additional specimens from the Niobrara Formation are referred to Enchodus machairus. Some Enchodus specimens from the Fox Hills Formation, including the holotype of E. dirus, may be better referred to Enchodus gladiolus, although none are complete enough to be certain. A nearly complete skull from Greece, which was previously identified as E. cf. E. dirus, is not conspecific with E. machairus.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2676733

ABSTRACT

Lambeosaurines are abundant in the Dinosaur Park Formation of Alberta, but are poorly known from the underlying Oldman Formation (Upper Cretaceous: Campanian). A new partial skull roof and braincase from the Comrey Sandstone Zone (middle Oldman) at the Milk River Ridge Reservoir locality in southern Alberta represents the first diagnostic material of an adult lambeosaurine from this formation. Derived characters of the frontal platform and braincase (including the steeply inclined frontal platform, boomerang-shaped dorsal surface of the frontals, and pendent alar processes of the basisphenoid) support the referral of this specimen to Parasaurolophini, as the stratigraphically lowest specimen with the skull roof and braincase preserved. The recognition of a new taxon is supported by a unique combination of characters, some resembling the inferred plesiomorphic condition for corythosaurians, including a triangular plateau on the parietal separating the interfrontal process from the sagittal crest, and the anterolaterodorsal orientation of the postorbital process of the laterosphenoid. Despite the large size and fused interfrontal contact, the prefrontal–postorbital contact is not strongly elevated, and the posterior margin of the frontal platform does not overhang the parietal, resembling the condition described in an immature Parasaurolophus from Dinosaur Provincial Park, and providing support for heterochrony in the evolution of the parasaurolophin skull roof. As one of relatively few diagnostic Albertan hadrosaurids older than the Dinosaur Park Formation, the new taxon provides significant new data on the diversification of Corythosauria, and the evolution of hadrosaurid communities in Laramidia.

LINK(S)

https://cdnsciencepub.com/doi/10.1139/cjes-2026-0013

ABSTRACT

The one-day field trip to the Lavini di Marco tracksite (Trentino-Alto Adige/Südtirol, NE Italy) offers the opportunity to appreciate one of the most extensive and interesting European dinosaur tracksites. The ichnoassemblage, Hettangian in age, is constituted by numerous quadrupedal trackways, referred to medium-sized sauropodomorphs, and hundreds of tridactyl footprints, produced by small- to large-sized theropods. The itinerary, developed in six stops, will focus on the most significant occurrences of the tracksite, highlighting the theropod biodiversity revealed by numerous tridactyl tracks, such as ROLM 198, ROLM 137 and ROLM 219, and the most spectacular and relevant quadrupedal trackways, such as ROLM 26, known as the "rock-climbing dinosaur" trackway, and ROLM 577, holotype of the ichnospecies Lavinipes cheminii.

LINK(S)

https://www.geologicalfieldtripsandmaps.com/296/issue-101/the-dinosaur-rise-in-the-southern-alps-field-trip-to-the-lavini-di-marco-tracksite-early-jurassic-ne-italy.html

ABSTRACT

The North American cheetah-like cat (Miracinonyx trumani) is a Late Pleistocene felid currently known from a handful of sites in North America. Its close relative, the mountain lion (Puma concolor), is much more widespread in the fossil record. However, owing to their close morphological similarity and the relatively recent description of M. trumani compared to many historical fossil accounts of P. concolor, it is likely that some latter specimens are misattributed. In this study, we examined fossil material attributed to P. concolor, which, based on original descriptions, may instead represent M. trumani specimens. We took linear measurements of cranial, dental, and postcranial material of known M. trumani and P. concolor specimens and compared them with these putative specimens of uncertain affinity. In order to differentiate between species, we performed discriminant function analyses (DFA) on ln transformed measurements. We also performed principal component analyses (PCA) in order to determine which characters drive variation between species. We found that postcranial material, particularly distal limb elements, reliably separate M. trumani from P. concolor. Cranial material fared worse overall at statistically distinguishing the species, though several cranial and dental characters could significantly separate the two. From the uncertain material we identified numerous previously unrecognized M. trumani specimens from three new localities in the U.S.A. and one in Mexico. This study greatly expands the known occurrences of M. trumani in North America and hints that many additional misidentified specimens may still be lurking in museum collections.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2687611

ABSTRACT

The Upper Cretaceous Guichón Formation (northwestern Uruguay) has yielded remains of notosuchian crocodyliforms, iguanodontian ornithopods, and saltasauroid titanosaurs. Two well-preserved sauropod caudal vertebrae from this unit are described herein from a new locality, Meseta de Artigas. The combination of synapomorphies allows the erection of a new taxon, Mesetasaurus protector gen. et sp. nov. It shares characters with members of the clade Aeolosaurini, such as strongly anteriorly inclined anterior face, neural arch placed at the level of the anterior border, anteriorly inclined neural spine, and long prezygapophyses. A phylogenetic analysis retrieves the new taxon deeply nested within Aeolosaurini. Given that Aeolosaurini is a Coniacian–Maastrichtian clade, this new sauropod provides additional evidence that suggests this age for the Guichón Formation. This is the second record of Aeolosaurini in Uruguay, and the second lineage of titanosaurian sauropods from the unit.

LINK(S)

https://www.ameghiniana.org.ar/index.php/ameghiniana/libraryFiles/downloadPublic/170

ABSTRACT

Mamenchisauridae is a group of long-necked non-neosauropodan eusauropod dinosaurs that were abundant in East Asia during the Middle to Late Jurassic, but their diversity and geographic distribution outside China remain poorly documented. Here we describe Uragasaurus kalasinensis gen. et sp. nov., a new sauropod dinosaur from the Phu Kradung Formation of northeastern Thailand. The new taxon is based on a well-preserved anterior dorsal vertebra exhibiting a distinctive combination of characters, including a unique Y-shaped configuration formed by the intraprezygapophyseal and single intraprezygapophyseal laminae and a camellate internal pneumatic structure within the centrum revealed by computed tomography (CT). Phylogenetic analyses recover the new taxon as an early-diverging member of Mamenchisauridae. This discovery represents the first formally named mamenchisaurid from Thailand and expands the known geographic distribution of the clade in Southeast Asia. The occurrence of this taxon in the Lower part of the Phu Kradung Formation also contributes to understanding faunal succession within the unit, supports an Upper Jurassic age for the lower part of the formation, and improves understanding of sauropod diversity in Southeast Asia during the Jurassic-Cretaceous transition.

LINK(S)

https://www.nature.com/articles/s41598-026-49822-3

https://www.nature.com/articles/s41598-026-49822-3.pdf

ABSTRACT

Here we provide Smilodon populator tooth mark patterning on their megaherbivore preys. Mark morphology demonstrates that Smilodon canines penetrated and processed cortical bone, refuting interpretations that considered them functionally fragile. These tooth marks have been compared with other carnivores and saber-toothed felid fossil sites. This spatial and chronological control provides direct evidence of predatory activity and constrains its temporal span, enabling evaluation of the ecological role of this hypercarnivore.

LINK(S)

https://link.springer.com/article/10.1186/s12862-026-02551-7

ABSTRACT

Tyrannosaurs were giant predatory dinosaurs that occupied the apex of Late Cretaceous food chains. Little is known about the early life and reproductive ecology of tyrannosaurs due to the extreme rarity of hatchling and juvenile fossils. We report bones of hatchlings (<1 yr) for Tyrannosaurus rex and Gorgosaurus libratus, weighing ~2.5 kg and ~2.4 kg, respectively, i.e., <0.1% of adult mass. Clutches were likely large. We conservatively estimate ~20 eggs in a small adult T. rex versus ~30 eggs in the largest T. rex, and clutches of ~15 eggs in G. libratus; larger clutches of 50 or even 100 eggs are not impossible. This suggests an r-selected reproductive strategy. Synchrotron scans reveal Haversian bone remodeling, suggesting that tyrannosaurs moved soon after hatching. Hatchling tyrannosaurs’ small size and precociality suggest limited parental care; teeth of hatchlings show wear suggesting that they fed on relatively large vertebrates. Tyrannosaurs had proportionately larger offspring than most reptiles, but relatively smaller hatchlings than Eumaniraptora and birds, suggesting retention of a primitive reproductive strategy intermediate between that of basal diapsids and birds. Multiple dinosaur lineages evolved large eggs independently, suggesting an evolutionary trend towards increased parental investment.

LINK(S)

https://www.mdpi.com/2079-7737/15/13/1090

ABSTRACT

Saber-toothed cats, representatives of the extinct subfamily Machairodontinae within Felidae, emerged in the early Miocene. Having established themselves across Africa, Eurasia, and the Americas, they played a key role over a long period in mammalian communities as dominant apex predators. In Africa, saber-toothed cats persisted until sometime between the Early and early Middle Pleistocene. The Americas housed the last representatives of the subfamily, Smilodon and Homotherium, up to the end of the Pleistocene Epoch. The fate of the subfamily in the Palearctic during its concluding phase remains uncertain. Prevailing views have long suggested that Homotherium, the last saber-toothed genus known in Eurasia, was no longer present there in the Late Pleistocene. However, recent, albeit isolated, discoveries revive the long-standing idea of a later persistence within Europe. This underscores the need for further investigation into the genus's late history across Eurasia. Northern Asia appears particularly important in this context, not only because of its underexplored fossil record, but also due to its likely role as a biogeographic link between European and North American populations during the Late Pleistocene.

We present two exceptionally well-preserved Homotherium upper canines recently discovered at widely separated Late Pleistocene localities in northeastern Siberia (Bolshoy Lyakhovsky Island, Arctic Ocean; and the Suruktakh, Kolyma River basin). Radiocarbon dating of bone collagen, combined with stratigraphic context, conclusively demonstrates that Homotherium occupied the northernmost regions of eastern Asia around 41,500–37,500 years ago. Together with the recent discovery of a 36,000-year-old Homotherium cub mummy from a locality situated between the two sites discussed here, our findings confirm the presence of saber-toothed cats in Asia until the terminal phase of the Pleistocene, expanding their known geographic range and supporting the hypothesis of a Holarctic distribution during this epoch. The study also raises questions regarding the taxonomic proximity of Late Pleistocene Homotherium specimens across Beringia and beyond.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0277379126002118

ABSTRACT

Since its discovery, Homo floresiensis—an extinct, short-statured, and small-brained hominin species from Flores, Indonesia—has often been ascribed unexpectedly advanced behaviors, such as hunting large game and using fire. Here, we report the results of a systematic taphonomic study sampling the proboscidean bone assemblage at Liang Bua where the frequency and locations of predatory marks, along with skeletal part profiles, show that Komodo dragons likely had primary access to these remains leaving behind only low-utility elements for H. floresiensis to scavenge. Moreover, no signs of intentional use of fire are present in the stratigraphic units associated with H. floresiensis. Together, these results suggest that H. floresiensis was not as behaviorally advanced as originally suggested and provides critical insights into the behavioral repertoire of H. floresiensis, raising important questions about its ancestry.

LINK(S)

https://www.science.org/doi/10.1126/sciadv.aeb7219

ABSTRACT

Elasmosaurids represent the most diverse clade of plesiosaurians during the Campanian-Maastrichtian. We report a new specimen with a well-preserved cranium and postcranium from the Maastrichtian levels of the Lefipán Formation, Chubut Province, Argentina, referred to Tuarangisaurus keyesi. This species was previously known only from Campanian-Maastrichtian deposits of New Zealand. Phylogenetic analysis recovers Tuarangisaurus keyesi as the basalmost member of Weddellonectia. The hyoid apparatus is preserved and consists of a single ossified element identified as ceratobranchial I, comparable to the condition observed in other plesiosaurians. The morphology of this element is consistent with a ram-feeding strategy.

LINK(S)

https://palaeo-electronica.org/content/2026/5903-first-record-of-tuarangisaurus-from-argentina

https://palaeo-electronica.org/content/pdfs/1531.pdf

ABSTRACT

Ontogenetic change is a major source of phenotypic variation among members of a species and is often of greater magnitude than the anatomical differences that distinguish closely related species. Ontogeny has therefore become a problematic confounding variable in vertebrate paleontology, especially in study systems distant from extant crown clades, rendering taxonomic hypothesis testing (a fundamental process in evolutionary biology) rife with difficulty. Paleontologists have adopted quantitative methods to compensate for the perception that juvenile specimens lack diagnostic apomorphies seen in their adult conspecifics. Here, I critically evaluate these methods and the assumptions that guide their interpretation using a μCT dataset comprising growth series of American and Chinese alligator. I find that several widespread assumptions are scientifically unjustifiable and that two popular methods—geometric morphometrics and cladistic analysis of ontogeny—have unacceptably high rates of type II error and present numerous procedural difficulties. However, I also identify a suite of ontogenetically invariant characters that differentiate the living species of Alligator throughout ontogeny. These characters overwhelmingly correspond to anatomical systems that develop before (and play a signaling role in) the development of the cranial skeleton itself, suggesting that their ontogenetic invariance is a consequence of the widely conserved vertebrate developmental program. These observations suggest that the architecture of the cranium is fixed early in embryonic development and that ontogenetic remodeling does not alter the topological relationships of the cranial bones or the soft tissue structures they house. I propose a general model for future taxonomic hypothesis tests in the fossil record, in which the hypothesis that two specimens are different ontogenetic stages of a single species can be falsified by the discovery of character differences that cannot be attributed plausibly to ontogenetic variation.

LINK(S)

https://www.cambridge.org/core/journals/paleobiology/article/resolving-the-ontogeny-problem-in-vertebrate-paleontology/2AFB934899437F2196EAA838D6CF5C22

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/2AFB934899437F2196EAA838D6CF5C22/S0094837326101055a.pdf/div-class-title-resolving-the-ontogeny-problem-in-vertebrate-paleontology-div.pdf

ABSTRACT

The top predators of arthropods, such as scorpions, spiders, and centipedes, are less commonly discovered in Mesozoic terrestrial Lagerstätten. Scorpiones belong to the class Arachnida within Arthropoda, with relatively few fossil records. The earliest scor- pions come from the mid Silurian, and at least some of them have been interpreted as transitional forms from sea to land. Despite being among the earliest terrestrial arthropods, fossil and living scorpions retain a largely conservative body plan. Mesozoic scorpions are mainly from mid-Cretaceous Burmese amber, whereas compression fossils of scorpions normally deposited in the strata are relatively rare except in the Late Triassic Keuper Sandstone Formation of England and the Early Cretaceous Crato Formation of Brazil.

Three fossil scorpions have been reported from China, including a Miocene scorpion Sinoscorpius shandongensis Hong from Shan- dong Province, a Devonian scorpion Hubeiscorpio gracilitarsis Walossek et al. from Hubei Province, and a Permian scorpion Eoscorpius sp. from Wuda, Nei Mongol. The Early Cretaceous Jehol Biota is internationally famous thanks to discoveries of exceptional fossils, including feathered dinosaurs, early birds, diverse mammals and pterosaurs, as well as some arthropod fossils which are mainly represented by insects and a few crustacean spe- cies. Here, we document the first scorpion, Jeholia longchengi gen. et sp. nov., from the Yixian Formation of Nei Mongol, uncover- ing a new member for this terrestrial ecosystem and the first Meso- zoic scorpion form China. This scorpion is unusually large among fossil taxa. We tentatively infer the potential predation relation- ships of the new fossil scorpion and reconstruct the trophic dynamics of Early Cretaceous Jehol palaeo-food webs.

The scorpion fossil studied here is housed at the Fossil Valley Museum in Chaoyang, China. It is preserved in dark grey mud- stones of the Yixian Formation from Heishangou Village, Chifeng City, Nei Mongol, but the precise geographical coordinates of the fossil locality remain unclear. The specimen was carefully prepared using a sharp knife. The photos were taken using a Canon EOS 5D Mark II camera with a Canon 100 mm macro lens attached and a Zeiss Stereo Discovery V20 stereo microscope. All images were stacked in Helicon Focus 7.0 and figure plates were arranged in Adobe Photoshop 2020. Measurements were taken using ImageJ. The guild-level palaeo-food web, including our fossil scorpion, was reconstructed based on the extrapolated diet dataset from the Jehol Biota by Matsukawa et al.. The predation relationships were identified by previous observations of abdominal contents from the Jehol fossils, along with inferences derived from ecologi- cal characteristics (Table S1 online). We calculated the Between- ness Centrality of each guild within the Jehol palaeo-food web. This metric measures how often species i falls on the shortest paths connecting all other species pairs. A species with high Betweenness Centrality is important because it mediates numerous indirect interactions between other species.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S2095927325000908#metrics

https://www.sciencedirect.com/sdfe/pdf/download/eid/1-s2.0-S2095927325000908/first-page-pdf

ABSTRACT

The evolutionary assembly of the flight-adapted bird body plan encompasses some of the most profound morphological changes in terrestrial vertebrate history. Beyond feathered wings, the short pygostyle-bearing tail has been pivotal to the clade’s ecological success. However, transition from the long bony tail to the short pygostyle-bearing tail remains a mystery, hindered by the scarcity of early branching avialans with transitional morphologies. Here, we report on a new avialan, Zhengheornis buyu, gen. et sp. nov., from the Upper Jurassic of southeastern China, suggesting that the vertebral reduction and shortening preceded pygostyle fusion in early avialan evolution, providing critical evidence for the stepwise evolution of the bird tail. Z. buyu is smaller than all known non-pygostylian paravians, expanding the species and body size diversity of stemward taxa.

LINK(S)

https://www.science.org/doi/10.1126/sciadv.aeb5202

ABSTRACT

The early Palaeocene Conflicto antarcticus reveals a mosaic pattern of brain and skull evolution relative to other Anseriformes. Despite its hyperinflated brain and ventrally displaced optic lobes, Conflicto lacks the Wulst, an absence shared with the Eocene Presbyornis and interpreted as a primitive trait for Neornithes. Enlarged olfactory bulbs suggest enhanced olfactory capabilities uncommon in modern birds, possibly compensating for the reduced visual and tactile specializations typically associated with filter feeding. The morphology of its straight, non-spatulate beak and the relatively undeveloped trigeminal system suggest a foraging strategy based more on ground-pecking than filtering. These findings provide critical insight into the early stages of anseriform evolution, indicating that key neural adaptations for filter feeding seen in modern taxa were absent or incipient in Conflicto. Moreover, Conflicto’s brain morphology suggests that several features evolved convergently across Neornithes.

LINK(S)

https://royalsocietypublishing.org/rsos/article/13/7/252544/482368/Unlocking-the-early-evolution-of-brain-and-feeding