The morphological variation of Polygnathus s.l. has been quantified using 3D geometric morphometrics in ten levels from the Puech de la Suque section (France) where Neopolygnathus cooccurs with Polygnathus s.s.. Four successive groups of levels sharing similar patterns of morphological variation have been identified. Within these groups, if size-related variation is accounted for, the two proposed genera Neopolygnathus and Polygnathus s.s. do not differ significantly in shape. The degree of expression of the aboral depression varies as a continuous and coherent gradient within each group. The frequency of conodonts with well-expressed depression however varies between the four groups, due to differences in the shape of the platform and in ontogenetic growth patterns. 

The genus Neopolygnathus is therefore not supported by the 3D morphometric analysis. The conodont elements being tooth-like structures involved in occlusion, the functional consequences of the morphological differences observed along the section requires further investigation.

Ankylosaurs are a characteristic group of dinosaurs recognised by their extensive covering of dermal armour (osteoderms) across their bodies. The Middle–Late Jurassic (Bathonian–Oxfordian) Oxford Clay Formation, UK, contains among the earliest known ankylosaur material, including osteoderms assigned to Sarcolestes and a few currently unidentified species. The formation is thus important for understanding early ankylosaur evolution. Here, we describe an osteoderm from the Oxford Clay of Peterborough that exhibits a different morphology to other osteoderms from this formation. The specimen, although incomplete along its transverse axis, measures 43 mm across its anteroposterior axis with a spine length of 52 mm. The osteoderm is subrectangular with a concave ventral surface and a low-lying spine on its dorsal surface that slightly extends beyond the posterior margin of the specimen base. This morphology is superficially more similar to the thoracic osteoderms of more derived Cretaceous ankylosaurs from North America (e.g. Borealopelta, Edmontonia), than to Oxford Clay specimens and other contemporaneous Jurassic ankylosaurs (e.g. Tianchisaurus). Although its isolated nature prevents reliable identification of the taxon and body part to which it belonged, the osteoderm nevertheless indicates a larger morphological diversity in the body armour of the earliest ankylosaurs than currently appreciated.

The fissure fill localities of southwest England and South Wales are well-known for preserving rich assemblages of predominantly small-bodied Late Triassic to Early Jurassic tetrapods, but many aspects of these assemblages remain contentious. The fissures have been hypothesized by some workers to have formed on an archipelago, with island effects invoked to explain aspects of the assemblages such as the abundance of small-bodied species. Procolophonids were a successful group of Triassic parareptiles, best known from Early to early Late Triassic assemblages, but are poorly known from the fissure fills. Here, we describe new procolophonid specimens from the Cromhall fissure that represent at least six individuals of different sizes, with much of the skeleton represented including well-preserved skull material. The Cromhall procolophonid shows strong similarities to Late Triassic procolophonids from Scotland, Brazil and North America, but both autapomorphies and a unique character combination demonstrate that it represents a new species. Phylogenetic analysis places the Cromhall taxon in a derived clade within Leptopleuroninae, together with Leptopleuron, Hypsognathus and Soturnia. The largest specimens of the Cromhall taxon demonstrate a body size that is similar to Leptopleuron and Hypsognathus, supporting other recent work questioning the insular dwarfism hypothesis for the fissure fill assemblages.

The Manda Beds of Tanzania have produced a diverse assemblage of Middle Triassic tetrapods including 6 dicynodont taxa. Recent examination of a death assemblage of multiple dicynodont species collected in 1963 by Charig and Cox and reposited in the Natural History Museum, London has identified a cranium and mandible clearly belonging to a single individual which is substantially different to the other Tanzanian dicynodonts. The presence of hypertrophied tusks, a squared off premaxilla tip, a triangular skull in dorsal view, and the lack of a ridge along the nasals indicate this individual has more similarities with the South American Dinodontosaurus than other taxa. However, it also has several unique features such as a bulbous posterior ridge on the premaxilla, incompletely fused splenials, and an anteroposteriorly short palatal area. This suggests this individual belongs to a novel taxon, and a phylogenetic analysis accompanied with statistical tests further support this hypothesis. Among the associated postcranial elements are strongly curved unguals never before reported in dicynodonts. If these unguals belong to the same taxon as the skull, the unique suite of adaptations would have facilitated a mode of foraging different to that of contemporary dicynodont taxa, allowing them to occupy separate ecological roles.

Plesiosaurs employed a distinctive four-flipper swimming method that granted them remarkable advantages in swimming speed and endurance. Previous investigations primarily focused on elucidating the mechanisms and benefits of this propulsion method using flume tank experiments. However, these experiments had notable limitations, such as the absence of rotational movement around the articular socket, and the exclusion of the plesiosaur body, neck, head, and tail.

In this study, we present recent developments that have significantly advanced our understanding of plesiosaur locomotion. Specifically, we have successfully developed a free-swimming plesiosaur robot that accurately replicates the body morphology and flipper kinematics of these extinct creatures. This innovative robot serves as a valuable experimental tool, allowing us to investigate various flipper shapes, kinematics, and the influence of head, neck, and tail morphologies.

Our novel approach, employing an accurate plesiosaur robot as a test platform, provides unprecedented insights into the evolutionary adaptations and locomotor capabilities of these marine reptiles. By gaining a deeper understanding of the hydrodynamics of plesiosaur swimming, we can acquire valuable knowledge applicable to both biological and engineering contexts. This knowledge holds great potential for advancements in underwater robotics and the development of biomimetic design principles.

Species richness is unevenly distributed across clades of all taxonomic ranks. Based on a body of theoretical work, and our own empirical findings, we propose that uneven species richness may be partially determined by varying morphological complexity between groups. While it is impossible to measure complexity directly, it is possible to derive proxies based on the morphology of particular structures. Specifically, the number of parts comprising a structure, their relative differentiation from one another, and the relative disorder of their arrangement, can be used to derive useful proxies. In this work, we derived an index of complexity for 983 extant species of bird, based on serial differentiation of bones in the limb skeleton. We showed that the mean complexity exhibited by extant bird clades correlates negatively with their species richness. Further, we showed that mean complexity correlates negatively with the ecological niche diversity for each clade. This simple proxy for ecological specialisation is also correlates positively with clade species richness. We suggest that these findings demonstrate complexity-mediated ecological constraint, which in turn limits the ability of clades to diversify. 

The Jurassic radiation of crown mammals has been linked to the acquisition of key physiological innovations, including the evolution of determinate patterns of rapid juvenile growth truncated at sexual maturity. These patterns are intrinsically related to the evolution of mammals’ endothermic physiology, the timing and mechanisms of which remain under considerable debate. We use synchrotron X-ray tomographic imaging of annual growth increments in the dental cementum of Early-to-Late Jurassic mammaliaforms (mammals and their closest ancestors) to map the origin and evolution of mammalian determinate growth. Non-mammalian mammaliaforms exhibited slow growth-rates with relatively little change through life. Early crown mammals developed significantly faster juvenile growth-rates that reduced at the attainment of sexual maturity, showing distinct contrasts in structure between juvenile and adult cementum. All fossils studied retained lower growth-rates, longer estimated maximum lifespans, and delayed sexual maturity relative to comparably sized extant mammals. Estimation of basal-metabolic-rates (BMRs) using lifespan also suggests that non-mammalian mammaliaforms retained low BMRs, while some fossil crown mammals had BMRs approaching the lowest values of extant mammals. These patterns suggest that the mammalian determinate growth strategy first evolved amongst early crown mammals during the mid-Jurassic mammalian adaptive radiation, although growth remained slower than in extant mammals.

Pterosaurs were a group of flying archosauromorph reptiles that appeared in the Late Triassic and became extinct at the end of the Cretaceous. While there have been numerous examinations of pterosaur flight capabilities, their modes of terrestrial locomotion remain poorly constrained. In this study, the terrestrial ecology of pterosaurs is reviewed using a novel methodological approach utilising ungual and claw sheath morphometrics.

Amniote claws are complex structures that are intimately connected to lifestyle and locomotory habits, and therefore can, by extension, yield intriguing data on ecology and function. Claw morphology presents an understudied yet promising model system for the study of ecology in extinct amniotes through comparisons with the ecomorphospace occupied by extant taxa.

To facilitate a comprehensive ecomorphospace comparison, a dataset of pterosaur claw photographs encompassing a large taxonomic diversity has been compiled. This data has revealed a hitherto unrecorded morphological diversity in pterosaur manual and pedal unguals, as well as variable relationships between ungual and claw sheath morphologies in different taxa. These valuable new insights further our understanding of pterosaur ecology and expand our knowledge of the morphological diversity present in amniote claws as a whole.

Cranial kinesis in birds allows the rotation of the upper beak relative to the skull via displacement of the palate. This important mechanism tends to be overlooked in feeding studies, but the cranial kinetic system may provide new insights into the form-function relationships between bird skulls and their ecology. 

Using a simple 2D four-bar linkage model, we modelled cranial kinesis using lateral images of 308 extant bird species. Kinematic Transmission (KT) and gape measurements were compared with feeding categories. We also compared these metrics with link lengths and considered these results in the context of four-bar biological systems as a whole.  

Although KT did not demonstrate strong relationships with feeding ecology, the addition of the beak to the 4-bar system permits significant separation of dietary groups by accommodating gape differences within the models. Additionally, we find that body size appears to constrain the feeding method employed by birds. Analysis of link lengths revealed that the output link (beak depth) is more strongly correlated with KT than the input (quadrate). This is despite the fact that within birds, the output link is not the shortest link, which was the trait previously believed to drive mechanical sensitivity in other biological four-bar systems.  

Eight of the original 37 Crystal Palace Dinosaurs sculptures have vanished in the last 170 years. Most of these constitute mammal reconstructions from the “Tertiary Island” and are poorly documented, frustrating efforts to understand their morphology and the circumstances surrounding their disappearances. An exception is the sculpture of the Eocene equoid Palaeotherium magnum, which was photographed and illustrated in relative detail before it was lost six decades ago. These records have allowed a replica P. magnum to be created in the first effort at replacing a lost Crystal Palace “Dinosaur” since 2003. Initiated by the Friends of Crystal Palace Dinosaurs charity, the replica was funded through public contributions and a grant from the Crystal Palace Park Trust, and was sculpted by Robert Nicholls in his Bristol studio. We estimate that the original P. magnum model exceeded 2 m in length and, instead of the tapir-like form suggested by leading Victorian scholars, its anatomy was primarily informed by African elephant species. Recreated in durable fibreglass, the replica was unveiled alongside the two surviving Crystal Palace palaeothere sculptures in June 2023. Future restorative work includes plans to recreate another lost palaeothere component, the original head of the sitting “Palaeotherium minus”.

Mammals have a distinctive masticatory system, and the distribution of bone in the mandible varies within and between species due to differences in form and function and remodelling in response to mechanical loading. Mass distribution and its functional significance have been well studied in mammalian limbs and locomotory biomechanics, but mandibles and mastication have largely been ignored. I investigated the degree to which material density variation influences centre of mass (CoM) to better understand the determinants of mandibular mass distribution and tested five estimation methods for agreement against an established standard. I estimated CoM for an interspecific sample of 40-adult-specimens (Orders Artiodactyla, Perissodactyla, Proboscidea) and an ontogenetic series of 15-individuals (Diceros bicornis), using analogue and CT-based methods. Mass distribution data estimated with, and without, specification of material density does not significantly differ. CoM may be accurately estimated using surface scans in adult specimens, and in the ontogenetic case, simple linear measurements. That CoM can be reliably approximated from external form alone across a functionally diverse group of taxa implies remodelling of the internal architecture of the mandible does not meaningfully contribute to mass distribution. The tested methods exhibit high agreement, allowing datasets to be composed using a variety of approaches.

The various shapes of birds’ eggs have fascinated scientists for many years. It is now possible to mathematically describe shape accurately, allowing exploration of the physical and ecological factors driving evolution of egg shape. However, there has been relatively little consideration of: 1) how egg shape is established in the oviduct, or 2) how eggs retain their shape, even without an external calcitic layer. Here I postulate a hypothesis that answers these questions. The hypothesis suggests that, as the egg mass (i.e., yolk and albumen) moves from the magnum into the isthmus, it is squeezed by the physical restriction imposed by the isthmus lumen and cannot easily move into the isthmus. As the leading edge of the egg mass enters the isthmus, the egg mass in the distal magnum is forced to bulge outwards, resulting in an asymmetrical shape. The various egg shapes observed in birds are hence, produced by the interaction between the size of the egg mass relative to female body mass, and the degree of the restriction of the isthmus. Thus, a large egg mass, i.e., relative to female body mass, entering a narrow isthmus will produce a pointed egg shape. If the egg mass is relatively small, and the isthmus lumen wide, more of the egg mass could enter the isthmus and the degree of asymmetry is reduced. It is further proposed that egg shape is fixed by the formation of the shell membranes in the isthmus because the constituent protein fibres permanently stick together as they are deposited in the isthmus.  The implications of the hypothesis for the diversity of egg shapes in birds (and reptiles), and for the deposition and characteristics of the calcitic egg, are wide-ranging.

Dinosaur embryos cause a lot of excitement in the scientific literature and are widely reported in the popular press. Well-preserved, articulated oviraptorosaur embryos in eggs are usually interpreted as representing a stage of development close to hatching because of their large size and good level of skeletal ossification. Here we explore how the developmental stage of oviraptorosaur embryos can be estimated, rather than assumed. Using quantitative methods in comparison with modern crocodilian embryos, it was shown that articulated oviraptorosaur embryos are small relative to their egg length which suggests a stage of development equivalent to around 50%–60% of the developmental period rather than being close to hatching. Moreover, many elements of the crocodilian skeleton are well ossified at this point of development. Misunderstandings about the stage of the developmental biology of these and other well-preserved embryos hampers our understanding of the true nature of reproductive biology and development of extinct species. Palaeontologists should adopt a more conservative approach for initial interpretation of new specimens. This is important, because misunderstandings in the minds of the public about dinosaur biology are hard to counter once poorly evidenced ideas have been reported around the world.

Avian flight is powered by a downstroke force generated by the pectoralis (P) muscle and an upstroke force generated by the supracoracoideus (SC) muscle. This analysis explored the allometry of flight muscles to test for isometry with body mass in birds more generally. Data for muscle masses for over 600 species, representing 28 orders, were used in phylogenetically controlled analysis of covariance to test for the effects of order on allometry of flight muscles. The pectoralis scaled isometrically with body mass, but the supracoracoideus muscle exhibited a slight but significant negative allometry. Both muscles showed significant effects of order, but this effect was greatest for the supracoracoideus. As well as wing-propelled diving birds, and hovering hummingbirds, tinamous, gamebirds, and pigeons, which exhibit burst flight, also had had a disproportionately large supracoracoideus. This is needed to generate a powerful upstroke to counter water-borne drag or gravity. Many other orders had a P:SC ratio around 10:1 but values of 20:1, recorded for raptors and owls, were associated with relatively small supracoracoideus muscle mass. Differing flight styles reflect variability in supracoracoideus mass, rather than pectoralis mass. The significance of this result will impact our understanding of how morphology impacts flight action of birds.

All modern kangaroos (Macropodidae) hop. It is likely that some extinct “giant “ (i.e., larger than extant species) kangaroos likely did not hop, or hopped only rarely. Extinct short-faced kangaroos (Sthenurinae) were likely bipedal striders while Protemnodon species (“giant wallabies”, closely related to modern large kangaroos, Macropodinae) were probably more quadrupedal than their extant relatives.

The astragalus, comprising part of the ankle joint, plays a key role in transmitting locomotory forces. Using Finite Element Analysis we investigated astragalar stresses during different simulated types of locomotion to see if different stress patterns could be determined among large kangaroos, extinct and extant. We varied body mass (transmitted over two legs or one, whether hopping [5x body mass], bounding quadrupedally or bipedal striding [both 2x body mass]) and the tibia/astragalus angle (90⁰ during hopping and bounding, 120⁰ during striding) and compared pairs of taxa of similar body masses. Hoppers showed greater stress in striding simulations than hopping simulations; the striders performed well in both simulations but better in striding. The likely more quadrupedal Protemnodon performed poorly all simulations except bounding, where its low stresses were similar to the other kangaroos. Our results thus support prior hypotheses of alternative locomotion in extinct giant kangaroos.

Tetrapods are rare in the early Carboniferous. Until recently, they were represented by a few disarticulated limb and girdle bones from Nova Scotia and the skeleton of Perderpes from Scotland. Discoveries in the Scottish Borders have greatly expanded our knowledge of post-Devonian tetrapods and six new taxa have been named and briefly described so far. One of these, Ossirarus kierani, represented by a single specimen from the coastal section of the Tournaisian Ballagan Formation at Burnmouth, comprises the disarticulated bones of the posterior half of the skull, the anterior portion of the axial skeleton, and parts of the pectoral girdle and forelimbs. Compared with Pederpes it is small, with an estimated skull length of 55 mm. Like Acanthostega, it has a preopercular and a lateral line system represented by pores. It shares with embolomeres, a tabular-parietal suture, an intertemporal and a long tabular horn. The gastrocentrous vertebrae resemble those of Caerorhachis and the brachial foramen pierces the humerus through the posterior edge, as in Mesanerpeton. Preliminary phylogenetic analyses place Ossirarus on the tetrapod stem-group, crownward of some – but not all – Devonian taxa. The topology of the tetrapod stem suggests that numerous lineages of Carboniferous tetrapods extended back into the Devonian.

Traversodontidae, a clade of gomphodont cynodonts, thrived during the Middle and Late Triassic, exhibiting a widespread distribution. Traversodon stahlekeri stands out as one of the earliest-known traversodontids. Discovered by Friedrich von Huene in 1936, the species is based on few remains found in the Chiniquá region, Dinodontosaurus AZ, Ladinian/early Carnian (Brazil). In more recent research, a new specimen (ULBRA PVT-049) was unearthed at the Bortolin Site (Dinodontosaurus AZ), offering invaluable insights into the skull anatomy and paleoneurology of the taxon. This discovery enabled the identification of previously unknown phylogenetic characters, enhancing our understanding of the species' evolutionary history. Additionally, the endocranial anatomy of T. stahleckeri was examined for the first time. Notably, the reconstruction of the cranial endocast revealed paleoneurological features consistent with non-gonfodontosuchine traversodontids, including the presence of an unossified zone and a pineal body. However, distinctively, the parietal foramen was closed in this specimen. The presence/absence of the parietal foramen in some traversodontids has been linked to ontogeny, with older individuals losing it while retaining the pineal body. These recent findings offer valuable contributions to understanding the evolutionary history and cranial characteristics of T. stahleckeri, shedding light on the diversity and adaptations of traversodontids.

Bird wings vary in size and morphology in terms of both size and number of feathers and the underlying skeletal anatomy. The number of primary remiges does not seem to vary much between bird species but, by contrast, the number of secondary remiges ranges between 6–40 depending on bird size. Given that the primaries are attached to the manus and the secondaries are attached to the ulna, it was predicted that as bone lengths increased then feather count would increase. Data were collected for 251 species from 25 different orders and phylogenetically controlled analysis explored the allometry between feather count and bone size. Number of primaries did not vary with manus size but the number of secondaries increased with ulna length, but only in some orders. For example, in Gruiformes, the number of secondary feathers increased concomittantly with ulna length but in the Passeriformes almost all species had nine secondary remiges. It is unclear why birds with an ulna length of 70 mm can have between 9 and 24 secondaries. Further research is needed to explore size dependent variation in the breadth of the feather vane and its ability to withstand aerodynamic forces generated during a wing beat.

Several Pleistocene kangaroo species greatly exceeded the size of the largest kangaroos alive today. With extant large kangaroos already experiencing unusually high stresses in their hindlimbs while hopping, the size of these extinct megafaunal kangaroos has prompted the question: were they able to hop at all? At what body size is a kangaroo too big to feasibly hop? Previous attempts to answer this question have mainly focussed on extrapolating the safety factors of the hindlimb tendons. Here, we use biomechanical calculations to test the assumptions of these studies, by investigating the strength of the bones, muscles, and tendons of the giant kangaroo hindlimb, and testing which is most likely to limit the hopping ability of these species. We also attempt to minimise the extrapolation of scaling patterns beyond extant data, instead referring to fossil measurements wherever possible. We found that the bones and muscles of the hindlimb were likely capable of supporting hopping in giant kangaroos. Meanwhile, the strength of the tendons was indeed the most likely limiting factor, supporting the assumptions of prior studies.

The genus Scutisorex, also known as the Hero Shrew, possesses a unique vertebral morphology; The Transverse processes of its lumbar vertebrae, as well as some of its thoracic vertebrae, are dorsoventrally expanded and covered in numerous tubercles that project along the craniocaudal plane. Despite detailed documentation of Scutisorex’s skeletal and muscular anatomy (at least with regards to the first found species, S. somereni), as well as analyses of trabecular bone and research into Scutisorex's biomechanical properties, the biological function of this extreme morphology remains unknown.

This study attempts to rectify this gap in research through ‘AutoBend’, a novel program that offers an automated approach to estimating the mobility of vertebral joints. The mobility of Scutisorex’s vertebral column is compared to those of Shrew’s with more typical Soricid morphology, and the impact of Scutisorex’s tubercles on mobility is assessed. The two key hypotheses tested are as follows; (1) That vertebral range of motion is lower in Scutisorex than in more typical Soricids and lower in the apparently more derived S. somereni than the apparently less derived S. thori, and (2) that in both species of Scutisorex, joints with higher tubercle counts will be less mobile.

We undertook a phylogenetic analysis of genetic and anatomical data focusing on golden moles (Chrysochloridae) and tenrecs (Tenrecidae). Our results support the now well-resolved topology for extant tenrecids, and the paraphyly of "Chrysochlorinae" and the genera Chrysochloris and Chlorotalpa as traditionally used. The oldest divergence within crown Chrysochloridae is likely the node separating Eremitalpa-Huetia or Eremitalpa alone from the remaining species. A Chrysochloris-Cryptochloris root appears most frequently under equally-weighted parsimony, or with few or no sampled tenrecids, suggesting it is artefactual. The tropical genus Huetia is among the most widely distributed and anatomically polymorphic in our sample. Eremitalpa and Huetia have a relatively unspecialized hyoid apparatus and short angular process of the dentary. These elements in Huetia show a particular resemblance to those of the Namibian fossil Namachloris, which we reconstruct as a stem chrysochlorid. Crown chrysochlorids are geologically younger than crown tenrecids, and likely diversified in the Miocene around the same time as the tenrecid genus Microgale. Fossils of both groups from Eocliff in Namibia are probably late Eocene to early Miocene in age.

The interplay between skull morphology and architecture of jaw muscles remains understudied, despite its importance in identifying functional and developmental constraints shaping head evolution. Combining data on muscular and skeletal anatomy in a phylogenetic context can provide a clearer picture of the integration of the musculoskeletal system and the functional and ecological implications of morphological change. Lepidosaurs show outstanding variation in skull anatomy and jaw adductor configuration, as well as a wide range of dietary habits, representing an ideal study case to investigate the relationship between osteology, myology and ecology. Here, we quantify mandibular disparity across Lepidosauria by applying 3D geometric morphometrics in a sample of over 80 species. The effect and covariation of muscular anatomy on mandibular shape is tested using phylogenetic comparative methods and different muscular parameters (muscle mass, PCSA) obtained from dissected specimens. Finally, we test the relationships between diet, mandibular shape and muscular anatomy. Our results show that mandibular shape is partly explained by phylogenetic relatedness, allometry and diet. Muscle architecture covaries with mandibular morphology, suggesting that the jaw and associated muscles have evolved as an integrated system in Lepidosauria, facilitating the acquisition of the remarkable ecological diversity of the clade.

The Collection at Lincoln has on display a fine specimen of a plesiosaur. It was found at the beginning of the last century in a brick pit within the city at a site now occupied by a primary school, who use it as their logo. It was on display during the 1960s but was  forgotten until it was rediscovered in the museum stores in the late 1990s. It has been identified as a member of the Microclididae from the Pliensbachian Lias and is one of the most complete pleiosaur  specimens from this period. It is partly in a limestone nodue which gives some eviedence for a hstory of predation by a large, torsion-feeding predator.

Another substantially complete plesiosaur, unfortunately (and typically!) missing a skull  in the museum collection is not on display. It is part of a collection passed on from Grantham Museum in the early 20s when they were no longer able to store their geological material. It has not be the subject of any research, and information on provenance is limited. It was found in the early part of the 20th century, and fortunately photographed in situ at the time using a large format camera. The glass plates have deteriorated over time but could still be scanned to give reasonably good images. 

It appears to be from the Middle Lias, and is possibly a rhomaleosaurid plesiosaur.

The diversification of archosauromorph reptiles from the Late Permian to Late Triassic is a classic example of an adaptive radiation. It has received significant attention from phylogenetic, morphological and ecological perspectives, but its spatial signature is understudied. I reconstruct the geographic origins of early archosauromorphs using a taxonomically updated, time-calibrated super tree. I then couple landscape connectivity analysis and high-resolution reconstructions of deep time climate and topography in a novel workflow (TARDIS – traversal and routes of dispersal in spacetime) to infer the phylogeographic structure of their radiation across the ecologically anachronous stage presented by Pangaea. Finally, I quantify their rates and routes of dispersal and rates of climate adaptation to examine the biogeographic constraints on their early evolutionary success. Preliminary results highlight that the deepest archosauromorph divergences took place in European Pangaea but later cladogenetic events were geographically disparate and frequently involved trans-equatorial dispersals. This indicates that that extreme climates across the supercontinent were not as robust biogeographic barriers as previously suspected and demonstrates the role that landscape connectivity analysis can play in reconstructing the spatial dynamics of evolutionary radiations.

Cryptoclidid plesiosaurs were widely distributed across the Northern hemisphere during the Late Jurassic, displaying regional endemism at a species level, with few genera shared between regions. In this study, we present two new specimens that offer new material from Kimmerosaurus, as well as the first recorded presence of this genus from the Boreal Region (Svalbard). The two new specimens are PMO 212.662 from the Slottsmøya Formation of Svalbard (Norway) and K2134 from the Kimmeridge Clay Formation (UK - Etches collection). K2134 includes a disarticulated partial skull and four cervical vertebrae. PMO 212.662 includes a partial skull with partially articulated axial and appendicular elements. Computed tomography of K2134 provides amazing imagery of the specimen – significantly adding details on the rostrum, palate, and cheek region for Kimmerosaurus langhami. K2134 is largely similar to the holotype of K. langhami, with some differences in the atlas-axis and braincase. PMO 212.662 shares the unique Kimmerosaurus trait of a lack of a sagittal crest, as well as aspects of braincase morphology. In addition, this specimen provides previously unknown insights into the morphology of the posterior cervical and dorsal axial skeleton. Phylogenetic analysis supports the close relationship of these two specimens with Kimmerosaurus.

Most jawed vertebrates exhibit lifelong tooth replacement (polyphyodonty), and there is a great drive to understand its developmental basis. Here, surface feature observations and X-ray micro-CT virtual sections are used to identify tooth replacement mechanisms in fossil and modern fish. Tooth replacement requires a ‘dental lamina’, an epithelial connection which enables only one tooth to be replaced by one successor, at any one time, and provides the putative stems cells required for long-term tooth renewal. However, ‘one-for-one’ replacement is not present in the crushing dentitions of an extinct group of fishes, the pycnodonts. Instead, tooth positioning suggests an opportunistic, gap-filling addition, where teeth fill any available space e.g. arising from tooth damage/loss. Contrastingly, in the modern fish specimens, tooth replacement mechanisms are recognisable, although seabream show unusual change in tooth size, shape, and positioning, over one tooth generation. Pycnodont, seabream and other crushing dentitions exhibit a close-packed, near-tessellating patterning. I hypothesise that in pycnodonts, gap-filling occurred by the oral epithelium retaining odontogenic potential throughout life, possibly facilitated by stem cells that generate taste buds. I also hypothesise that tooth patterning in crushing dentitions is an adaptive phenotypic response to mechanical strain at the crushing surface, a known phenomenon in cichlids.

The vast majority of pterosaurs are characterized by large, elongate skulls. Projecting out in front of the body, these large heads must have had an aerodynamic effect. The working hypothesis of the present study is that these oversize heads were used to control the left-right motions of the body during flight. Using digital models of six, long-tailed “rhamphorhyncoids” and six, short-tailed pterodactlyoids, the turning moments associated with the head+neck showed an isometric correspondence with the rotational inertia of the whole body about a vertical axis in both groups.  Turning moments come from calculating the lateral area of the head (plus any crests) and determining the associated lift coefficient as a function of flight speed. Rotational inertias were calculated from the three-dimensional mass distribution of the axial body, the limbs and the flight membranes. Substantial tail fins at the end of the tail are only known from specimens of Rhamphorhynchus muensteri. Unlike other pterosaurs, the head moments of Rhamphorhynchus lagged behind their rotational inertias. However, the tail fins provide additional turning moments in Rhamphorhynchus, and suggest a flight style different from other tailed pterosaurs.