Size and shape heterodonty in the early Permian synapsid Mesenosaurus efremovi.

Paleozoic synapsids represent the first chapter in the evolution of this large clade that includes mammals. These fascinating terrestrial vertebrates were the first amniotes to successfully adapt to a wide range of feeding strategies, reflected by their varied dental morphologies. Evolution of the marginal dentition on the mammalian side of amniotes is characterized by strong, size and shape heterodonty, with the late Permian therapsids showing heterodonty with the presence of incisiform, caniniform, and multicuspid molariform dentition. Rarity of available specimens has previously prevented detailed studies of dental anatomy and evolution in the initial chapter of synapsid evolution, when synapsids were able to evolve dentition for insectivory, herbivory, and carnivory. Numerous teeth, jaw elements, and skulls of the hypercarnivorous varanopid Mesenosaurus efremovi have been recently discovered in the cave systems near Richards Spur, Oklahoma, permitting the first detailed investigation of the dental anatomy of a Paleozoic tetrapod using multiple approaches, including morphometric and histological analyses. As a distant stem mammal, Mesenosaurus is the first member of this large and successful clade to exhibit a type of dental heterodonty that combines size and morphological (shape) variation of the tooth crowns. Here we present the first evidence of functional differentiation in the dentition of this early synapsid, with three distinct dental regions having diverse morphologies and functions. The quality and quantity of preserved materials has allowed us to identify the orientation and curvature of the carinae (cutting edges), and the variation and distribution of the ziphodonty (serrations) along the carinae. The shape-related heterodonty seen in this taxon may have contributed to this taxon's ability to be a successful mid-sized predator in the taxonomically diverse community of early Permian carnivores, but may have also extended the ecological resilience of this clade of mid-sized predators across major faunal and environmental transitions.

Neutron Capture Enhances Dose and Reduces Cancer Cell Viability in and out of Beam During Helium and Carbon Ion Therapy.

PURPOSE: Neutron capture enhanced particle therapy (NCEPT) is a proposed augmentation of charged particle therapy that exploits thermal neutrons generated internally, within the treatment volume via nuclear fragmentation, to deliver a biochemically targeted radiation dose to cancer cells. This work is the first experimental demonstration of NCEPT, performed using both carbon and helium ion beams with 2 different targeted neutron capture agents (NCAs). METHODS AND MATERIALS: Human glioblastoma cells (T98G) were irradiated by carbon and helium ion beams in the presence of NCAs [10B]-BPA and [157Gd]-DOTA-TPP. Cells were positioned within a polymethyl methacrylate phantom either laterally adjacent to or within a 100 × 100 × 60 mm spread out Bragg peak (SOBP). The effect of NCAs and location relative to the SOBP on the cells was measured by cell growth and survival assays in 6 independent experiments. Neutron fluence within the phantom was characterized by quantifying the neutron activation of gold foil. RESULTS: Cells placed inside the treatment volume reached 10% survival by 2 Gy of carbon or 2 to 3 Gy of helium in the presence of NCAs compared with 5 Gy of carbon and 7 Gy of helium with no NCA. Cells placed adjacent to the treatment volume showed a dose-dependent decrease in cell growth when treated with NCAs, reaching 10% survival by 6 Gy of carbon or helium (to the treatment volume), compared with no detectable effect on cells without NCA. The mean thermal neutron fluence at the center of the SOBP was approximately 2.2 × 109 n/cm2/Gy (relative biological effectiveness) for the carbon beam and 5.8 × 109 n/cm2/Gy (relative biological effectiveness) for the helium beam and gradually decreased in all directions. CONCLUSIONS: The addition of NCAs to cancer cells during carbon and helium beam irradiation has a measurable effect on cell survival and growth in vitro. Through the capture of internally generated neutrons, NCEPT introduces the concept of a biochemically targeted radiation dose to charged particle therapy. NCEPT enables the established pharmaceuticals and concepts of neutron capture therapy to be applied to a wider range of deeply situated and diffuse tumors, by targeting this dose to microinfiltrates and cells outside of defined treatment regions. These results also demonstrate the potential for NCEPT to provide an increased dose to tumor tissue within the treatment volume, with a reduction in radiation doses to off-target tissue.

Paleozoic cave system preserves oldest-known evidence of amniote skin.

The richest and most diverse assemblage of early terrestrial tetrapods is preserved within the infilled cave system of Richards Spur, Oklahoma (289-286 Mya1). Some of the oldest-known terrestrial amniotes2,3 are exquisitely preserved here because of early impregnation and encasement of organic material by oil-seep hydrocarbons within rapidly deposited clay-rich cave sediments under toxic anoxic conditions.4 This phenomenon has also afforded the preservation of exceedingly rare integumentary soft tissues, reported here, providing critical first evidence into the anatomical changes marking the transition from the aquatic and semiaquatic lifestyles of anamniotes to the fully terrestrial lifestyles of early amniotes. This is the first record of a skin-cast fossil (3D carbonization of the skin proper) from the Paleozoic Era and the earliest known occurrence of epidermal integumentary structures. We also report on several compression fossils (carbonized skin impressions), all demonstrating similar external morphologies to extant crocodiles. A variety of previously unknown ossifications, as well as what are likely palpebral ossifications of the deeper dermis layer of the skin, are also documented. These fossils also serve as invaluable references for paleontological reconstructions. Chromatographic analysis of extractable hydrocarbons from bone and cave samples indicates that the source rock is the Devonian age Woodford Shale. Hydrocarbons derived from ancient marine organisms interacting with geologically younger terrestrial vertebrates have therefore resulted in the oldest-known preservation of amniote skin proper.

Skeletal anatomy of the early Permian parareptile Delorhynchus with new information provided by neutron tomography.

Detailed description of the holotype skeleton of Delorhynchus cifellii, made possible through the use of neutron tomography, has yielded important new information about the cranial and postcranial anatomy of this early Permian acleistorhinid parareptile. Hitherto unknown features of the skull include a sphenethmoid, paired epipterygoids and a complete neurocranium. In addition, the stapes has been exposed in three dimensions for the first time in an early parareptile. Postcranial material found in articulation with the skull in this holotype allows for the first detailed description of vertebrae, ribs, shoulder girdle and humerus of an acleistorhinid parareptile, allowing for a reevaluation of the phylogenetic relationships of this taxon with other acleistorhinids, and more broadly among parareptiles. Results show that Delorhynchus is recovered as the sister taxon of Colobomycter, and 'acleistorhinids' now include Lanthanosuchus.

Response to comment on "Exceptional preservation of organs in Devonian placoderms from the Gogo largerstätte".

Jensen et al. (1) question evidence presented of a chambered heart within placoderms, citing its small size and apparently ventral atrium. However, they fail to note the belly-up orientation of the placoderm within one nodule, and the variability of heart morphology within extant taxa. Thus, we remain confident in our interpretation of the mineralized organ as the heart.

A nearly complete skull of the sauropod dinosaur Diamantinasaurus matildae from the Upper Cretaceous Winton Formation of Australia and implications for the early evolution of titanosaurs.

Titanosaurian sauropod dinosaurs were diverse and abundant throughout the Cretaceous, with a global distribution. However, few titanosaurian taxa are represented by multiple skeletons, let alone skulls. Diamantinasaurus matildae, from the lower Upper Cretaceous Winton Formation of Queensland, Australia, was heretofore represented by three specimens, including one that preserves a braincase and several other cranial elements. Herein, we describe a fourth specimen of Diamantinasaurus matildae that preserves a more complete skull-including numerous cranial elements not previously known for this taxon-as well as a partial postcranial skeleton. The skull of Diamantinasaurus matildae shows many similarities to that of the coeval Sarmientosaurus musacchioi from Argentina (e.g. quadratojugal with posterior tongue-like process; braincase with more than one ossified exit for cranial nerve V; compressed-cone-chisel-like teeth), providing further support for the inclusion of both taxa within the clade Diamantinasauria. The replacement teeth within the premaxilla of the new specimen are morphologically congruent with teeth previously attributed to Diamantinasaurus matildae, and Diamantinasauria more broadly, corroborating those referrals. Plesiomorphic characters of the new specimen include a sacrum comprising five vertebrae (also newly demonstrated in the holotype of Diamantinasaurus matildae), rather than the six or more that typify other titanosaurs. However, we demonstrate that there have been a number of independent acquisitions of a six-vertebrae sacrum among Somphospondyli and/or that there have been numerous reversals to a five-vertebrae sacrum, suggesting that sacral count is relatively plastic. Other newly identified plesiomorphic features include: the overall skull shape, which is more similar to brachiosaurids than 'derived' titanosaurs; anterior caudal centra that are amphicoelous, rather than procoelous; and a pedal phalangeal formula estimated as 2-2-3-2-0. These features are consistent with either an early-branching position within Titanosauria, or a position just outside the titanosaurian radiation, for Diamantinasauria, as indicated by alternative character weighting approaches applied in our phylogenetic analyses, and help to shed light on the early assembly of titanosaurian anatomy that has until now been obscured by a poor fossil record.

Neurosensory anatomy and function in Seymouria.

Seymouria is among the best-known stem amniotes and holds an important phylogenetic position for discussions of amniote evolution. Previous work has focused primarily on the osteology of Seymouria, with recent interest turning to the application of computed tomography (CT) to study the internal features. We utilized neutron CT to reconstruct the first virtual cranial endocast and the first complete otic endocasts of Seymouria, revealing previously unrecognized details of its palaeoneuroanatomy. The brain and inner ear of Seymouria are largely plesiomorphic relative to later-diverging crown amniotes, showing no indication of increased encephalization or braincase ossification. Our results also clarify the plesiomorphic condition for carotid artery morphology in amniotes, with Seymouria showing a similar condition to basal members of both the synapsid and sauropsid lineages. The reconstructed neuroanatomy also indicates that Seymouria did not possess any particular neuroanatomical specializations, despite the probable presence of an impedance matching hearing system.

New specimens of the early Permian apex predator Varanops brevirostris at Richards Spur, Oklahoma, with histological information about its growth pattern.

An articulated pelvic region and additional isolated material of Varanops brevirostris, which are indistinguishable from those of the generotype from the Cacops bonebed, demonstrate the presence of this large varanopid at the Richards Spur locality. The articulated specimen includes lumbar, sacral, and anterior caudal vertebrae, partial pelvis, femur, and proximal part of tibia, confirming the autapomorphies previously suggested for this species. These include the presence of distinct blade-like shapes of the neural spines in the sacral region, the presence of deeply excavated pubis, and the presence of a distinct transverse ridge on the ventral surface of the femur distal to the intertrochanteric fossa. It has also been found that the transverse ridges and grooves become larger during ontogeny since the juvenile specimen did not exhibit a well-developed ridge. Histological analysis of isolated limb bones and neutron computed tomography (nCT) of the articulated specimen indicate that the latter likely belonged to an adult individual. This is in contrast to the other varanopid at Richards Spur, the significantly smaller, more gracile predator Mesenosaurus efremovi, which also shows the presence of growth lines and the external fundamental system with an estimated minimum age of fourteen.

Endocasts of the basal sauropsid Captorhinus reveal unexpected neurological diversity in early reptiles.

Captorhinids are a group of Paleozoic amniotes that represents one of the earliest-diverging clades of eureptiles. Although captorhinids are one of the best-known and most well-studied clades of early amniotes, their palaeoneuroanatomy has gone largely unexamined. We utilized neutron computed tomography to study the virtual cranial and otic endocasts of two captorhinid specimens. The neurosensory anatomy of captorhinids shows a mixture of traits considered plesiomorphic for sauropsids (no expansions of the cerebrum or olfactory bulbs, low degree of encephalization, low ossification of the otic capsule) and those considered more derived, including moderate cephalic and pontine flexures and a dorsoventrally tall bony labyrinth. The inner ear clearly preserves the elliptical, sub-orthogonal canals and the short, rounded vestibule, along with an unusually enlarged lateral canal and a unique curvature of the posterior canal. The reconstructed neurosensory anatomy indicates that captorhinids were sensitive to slightly higher frequencies than many of their contemporaries, likely reflecting differences in body size across taxa, while the morphology of the maxillary canal suggests a simple, tubular condition as the plesiomorphic state for Sauropsida and contributes to the ongoing discussions regarding the phylogenetic placement of varanopids. This study represents the first detailed tomographic study of the brain and inner ear of any basal eureptile. The new data described here reveal that the neuroanatomy of early sauropsids is far more complex and diverse than previously anticipated, and provide impetus for further exploration of the palaeoneuroanatomy of early amniotes.

An intriguing new diapsid reptile with evidence of mandibulo-dental pathology from the early Permian of Oklahoma revealed by neutron tomography.

The initial stages of diapsid evolution, the clade that includes extant reptiles and the majority of extinct reptilian taxa, is surprisingly poorly known. Notwithstanding the hypothesis that varanopids are diapsids rather than synapsids, there are only four araeoscelidians and one neodiapsid present in the late Carboniferous and early Permian. Here we describe the fragmentary remains of a very unusual new amniote from the famous cave deposits near Richards Spur, Oklahoma, that we recognize as a diapsid reptile, readily distinguishable from all other early amniotes by the unique dentition and lower jaw anatomy. The teeth have an unusual reeding pattern on the crown (long parallel ridges with rounded surfaces), with some teeth posteriorly tilted and strongly recurved, while a ventral protuberance forms the anterior terminus of the dentary. Overall, the lower jaw is unusually slender with a flattened ventral surface formed by the dentary and splenial anteriorly and the angular in the mid-region. The presence of a very slender triradiate jugal revealed through computed tomography confirms the existence of a large lower temporal fenestra, while the medial edge of the maxilla and the anatomy of the palatine confirm the presence of a large suborbital fenestra. Computed tomography of this new taxon reveals maxillary innervation that is characteristically reptile, not synapsid. Although no other definitively identifiable skull roof elements exist, the suborbital fenestra borders preserved on the palatine and maxilla supports the hypothesis that this is a diapsid reptile. Interestingly, the right dentary shows evidence of pathology, a rarely reported occurrence in Paleozoic amniotes, with several empty tooth sockets filled by bone. This small predator with delicate subthecodont implanted dentition provides strong evidence that diapsid reptiles were already diversifying rapidly in the early Permian, but likely were relatively rare members of terrestrial vertebrate assemblages.

Exceptional preservation of organs in Devonian placoderms from the Gogo lagerstätte.

The origin and early diversification of jawed vertebrates involved major changes to skeletal and soft anatomy. Skeletal transformations can be examined directly by studying fossil stem gnathostomes; however, preservation of soft anatomy is rare. We describe the only known example of a three-dimensionally mineralized heart, thick-walled stomach, and bilobed liver from arthrodire placoderms, stem gnathostomes from the Late Devonian Gogo Formation in Western Australia. The application of synchrotron and neutron microtomography to this material shows evidence of a flat S-shaped heart, which is well separated from the liver and other abdominal organs, and the absence of lungs. Arthrodires thus show the earliest phylogenetic evidence for repositioning of the gnathostome heart associated with the evolution of the complex neck region in jawed vertebrates.

Earliest evidence for fruit consumption and potential seed dispersal by birds.

The Early Cretaceous diversification of birds was a major event in the history of terrestrial ecosystems, occurring during the earliest phase of the Cretaceous Terrestrial Revolution, long before the origin of the bird crown-group. Frugivorous birds play an important role in seed dispersal today. However, evidence of fruit consumption in early birds from outside the crown-group has been lacking. Jeholornis is one of the earliest-diverging birds, only slightly more crownward than Archaeopteryx, but its cranial anatomy has been poorly understood, limiting trophic information which may be gleaned from the skull. Originally hypothesised to be granivorous based on seeds preserved as gut contents, this interpretation has become controversial. We conducted high-resolution synchrotron tomography on an exquisitely preserved new skull of Jeholornis, revealing remarkable cranial plesiomorphies combined with a specialised rostrum. We use this to provide a near-complete cranial reconstruction of Jeholornis, and exclude the possibility that Jeholornis was granivorous, based on morphometric analyses of the mandible (3D) and cranium (2D), and comparisons with the 3D alimentary contents of extant birds. We show that Jeholornis provides the earliest evidence for fruit consumption in birds, and indicates that birds may have been recruited for seed dispersal during the earliest stages of the avian radiation. As mobile seed dispersers, early frugivorous birds could have expanded the scope for biotic dispersal in plants, and might therefore explain, at least in part, the subsequent evolutionary expansion of fruits, indicating a potential role of bird-plant interactions in the Cretaceous Terrestrial Revolution.

Birds and plants have a close relationship that has developed over millions of years. Birds became diverse and abundant around 135 million years ago. Shortly after, plants started developing new and different kinds of fruits. Today, fruit-eating birds help plants to reproduce by spreading seeds in their droppings. This suggests that birds and plants have coevolved, changing together over time. But it is not clear exactly how their relationship started. One species that might hold the answers is an early bird species known as Jeholornis. It lived in China in the Early Cretaceous, around 120 million years ago. Palaeontologists have discovered preserved seeds inside its fossilised remains. The question is, how did they get there? Some birds eat seeds directly, cracking them open or grinding them up in the stomach to extract the nutrients inside. Other birds swallow seeds when they are eating fruit. If Jeholornis belonged to this second group, it could represent one of the early steps in plant-bird coevolution. Hu et al. scanned and reconstructed a preserved Jeholornis skull and compared it to the skulls, especially the mandibles, of modern birds, including species that grind seeds, species that crack seeds and species that eat fruits, leaving the seeds whole. The analyses ruled out seed cracking. But it could not distinguish between seed grinding and fruit eating. Hu et al. therefore compared the seed remains found inside Jeholornis fossils to seeds eaten by modern birds. The fossilised seeds were intact and showed no evidence of grinding. This suggests that Jeholornis ate whole fruits for at least part of the year. At around the time Jeholornis was alive, the world was entering a phase called the Cretaceous Terrestrial Revolution, which was characterized by an explosion of new species and an expansion of both flowering plants and birds. This finding opens new avenues for scientists to explore how plant and birds might have evolved together. Similar analyses could unlock new information about how other species interacted with their environments.

An earliest Triassic age for Tasmaniolimulus and comments on synchrotron tomography of Gondwanan horseshoe crabs.

Constraining the timing of morphological innovations within xiphosurid evolution is central for understanding when and how such a long-lived group exploited vacant ecological niches over the majority of the Phanerozoic. To expand the knowledge on the evolution of select xiphosurid forms, we reconsider the four Australian taxa: Austrolimulus fletcheri, Dubbolimulus peetae, Tasmaniolimulus patersoni, and Victalimulus mcqueeni. In revisiting these taxa, we determine that, contrary to previous suggestion, T. patersoni arose after the Permian and the origin of over-developed genal spine structures within Austrolimulidae is exclusive to the Triassic. To increase the availability of morphological data pertaining to these unique forms, we also examined the holotypes of the four xiphosurids using synchrotron radiation X-ray tomography (SRXT). Such non-destructive, in situ imaging of palaeontological specimens can aid in the identification of novel morphological data by obviating the need for potentially extensive preparation of fossils from the surrounding rock matrix. This is particularly important for rare and/or delicate holotypes. Here, SRXT was used to emphasize A. fletcheri and T. patersoni cardiac lobe morphologies and illustrate aspects of the V. mcqueeni thoracetronic doublure, appendage impressions, and moveable spine notches. Unfortunately, the strongly compacted D. peetae precluded the identification of any internal structures, but appendage impressions were observed. The application of computational fluid dynamics to high-resolution 3D reconstructions are proposed to understand the hydrodynamic properties of divergent genal spine morphologies of austrolimulid xiphosurids.

A new Early Cretaceous lizard in Myanmar amber with exceptionally preserved integument.

We here report on a well-preserved juvenile lizard specimen in Albian amber (ca. 110 mya) from the Hkamti site (Myanmar). This new taxon is represented by an articulated skull and the anterior portion of the trunk, including the pectoral girdle and forelimbs. The scleral ossicles and eyelid are also visible, and the specimen exhibits pristine detail of the integument (of both head and body). In a combined molecular and morphological analysis, it was consistently recovered as a scincoid lizard (Scinciformata), as sister to Tepexisaurus + Xantusiidae. However, the phylogenetic position of the new taxon should be interpreted with caution as the holotype is an immature individual. We explored the possibility of miscoding ontogenetically variable characters by running alternative analyses in which these characters were scored as missing data for our taxon. With the exception of one tree, in which it was sister to Amphisbaenia, the specimen was recovered as a Pan-xantusiid. Moreover, we cannot rule out the possibility that it represents a separate lineage of uncertain phylogenetic position, as it is the case for many Jurassic and Cretaceous taxa. Nonetheless, this fossil offers a rare opportunity to glimpse the external appearance of one group of lizards during the Early Cretaceous.

Neurosensory anatomy of Varanopidae and its implications for early synapsid evolution.

Varanopids are a group of Palaeozoic terrestrial amniotes which represent one of the earliest-diverging groups of synapsids, but their palaeoneurology has gone largely unstudied and recent analyses have challenged their traditional placement within synapsids. We utilized computed tomography (CT) to study the virtual cranial and otic endocasts of six varanopids, including representative taxa of both mycterosaurines and varanodontines. Our results show that the varanopid brain is largely plesiomorphic, being tubular in shape and showing no expansion of the cerebrum or olfactory bulbs, but is distinct in showing highly expanded floccular fossae. The housing of the varanopid bony labyrinth is also distinct, in that the labyrinth is bounded almost entirely by the supraoccipital-opisthotic complex, with the prootic only bordering the ventral portion of the vestibule. The bony labyrinth is surprisingly well-ossified, clearly preserving the elliptical, sub-orthogonal canals, prominent ampullae, and the short, undifferentiated vestibule; this high degree of ossification is similar to that seen in therapsid synapsids and supports the traditional placement of varanopids within Synapsida. The enlarged anterior canal, together with the elliptical, orthogonal canals and enlarged floccular fossa, lend support for the fast head movements indicated by the inferred predatory feeding mode of varanopids. Reconstructed neurosensory anatomy indicates that varanopids may have a much lower-frequency hearing range compared to more derived synapsids, suggesting that, despite gaining some active predatory features, varanopids retain plesiomorphic hearing capabilities. As a whole, our data reveal that the neuroanatomy of pelycosaur-grade synapsids is far more complex than previously anticipated.

High-resolution high-throughput thermal neutron tomographic imaging of fossiliferous cave breccias from Sumatra.

We employ high-throughput thermal-neutron tomographic imaging to visualise internal diagnostic features of dense fossiliferous breccia from three Pleistocene cave localities in Sumatra, Indonesia. We demonstrate that these seemingly homogeneous breccias are an excellent source of data to aid in determining taphonomic and depositional histories of complex depositional sites such as tropical caves. X-ray Computed Tomographic (CT) imaging is gaining importance amongst palaeontologists as a non-destructive approach to studying fossil remains. Traditional methods of fossil preparation risk damage to the specimen and may destroy contextual evidence in the surrounding matrix. CT imaging can reveal the internal composition and structure of fossils contained within consolidated sediment/rock matrices prior to any destructive mechanical or chemical preparation. Neutron computed tomography (NCT) provides an alternative contrast to X-rays, and in some circumstances, is capable of discerning denser matrices impenetrable to or yielding no contrast with CT imaging. High-throughput neutron imaging reduces neutron fluence during scanning which means there is less residual neutron-induced radioactivation in geological samples; allowing for earlier subsequent analyses. However, this approach remains unutilised in palaeontology, archaeology or geological surveys. Results suggest that the primary agents in the formation of the breccias and concentration of incorporated vertebrate remains are several rapid depositional phases of water and sediment gravity flow. This study highlights the potential for future analyses of breccia deposits in palaeontological studies in caves around the world.

Unusual morphology in the mid-Cretaceous lizard Oculudentavis.

Oculudentavis khaungraae was described based on a tiny skull trapped in amber. The slender tapering rostrum with retracted narial openings, large eyes, and short vaulted braincase led to its identification as the smallest avian dinosaur on record, comparable to the smallest living hummingbirds. Despite its bird-like appearance, Oculudentavis showed several features inconsistent with its original phylogenetic placement. Here, we describe a more complete specimen that demonstrates Oculudentavis is actually a bizarre lizard of uncertain position. The new specimen is described as a new species within the genus Oculudentavis. The new interpretation and phylogenetic placement highlight a rare case of convergent evolution in skull proportions but apparently not in morphological characters. Our results re-affirm the importance of Myanmar amber in yielding unusual taxa from a forest ecosystem rarely represented in the fossil record.

Enigmatic amphibians in mid-Cretaceous amber were chameleon-like ballistic feeders.

Albanerpetontids are tiny, enigmatic fossil amphibians with a distinctive suite of characteristics, including scales and specialized jaw and neck joints. Here we describe a new genus and species of albanerpetontid, represented by fully articulated and three-dimensional specimens preserved in amber. These specimens preserve skeletal and soft tissues, including an elongated median hyoid element, the tip of which remains embedded in a distal tongue pad. This arrangement is very similar to the long, rapidly projecting tongue of chameleons. Our results thus suggest that albanerpetontids were sit-and-wait ballistic tongue feeders, extending the record of this specialized feeding mode by around 100 million years.

Characterizing concrete corrosion below sewer tidal levels at chemically dosed locations.

Unexplainable concrete softening below the water line has been observed by Sydney Water in their gravity sewer network, some of which is subjected to corrosion control methods using chemical ferrous chloride (FeCl2) dosing of the wastewater. We applied a combination of physical and chemical tools to determine the properties of the top 20 mm of concrete cores recovered from sewer pipes. These techniques consist of neutron tomographic imaging, scanning electron microscopy, hardness mapping, and pH profiling. Concrete cores were collected from roof (crown), tidal (wall) and below flow regions of gravity sewer pipes of Sydney Water's wastewater system from locations that received no treatment as well as locations dosed with FeCl2. All samples showed a degree of softening of the surface exposed to the sewerage with an associated depletion in calcium concentration and reduced pH in the same regions.

Thecodont tooth attachment and replacement in bolosaurid parareptiles.

Permian bolosaurid parareptiles are well-known for having complex tooth crowns and complete tooth rows in the jaws, in contrast to the comparatively simple teeth and frequent replacement gaps in all other Paleozoic amniotes. Analysis of the specialized dentition of the bolosaurid parareptiles Bolosaurus from North America and Belebey from Russia, utilizing a combination of histological and tomographic data, reveals unusual patterns of tooth development and replacement. The data confirm that bolosaurid teeth have thecodont implantation with deep roots, the oldest known such example among amniotes, and independently evolved among much younger archosauromorphs (including dinosaurs and crocodilians) and among synapsids (including mammals). High-resolution CT scans were able to detect the density boundary between the alveolar bone and the jawbone, as confirmed by histology, and revealed the location and size of developing replacement teeth in the pulp cavity of functional teeth. Evidence provided by the paratype dentary of Belebey chengi indicates that replacement teeth are present along the whole tooth row at slightly different stages of development, with the ontogenetically more developed teeth anteriorly, suggesting that tooth replacement was highly synchronized. CT data also show tooth replacement is directly related to the presence of lingual pits in the jaw, and that migration of tooth buds occurs initially close to these resorption pits to a position immediately below the functional tooth within its pulp cavity. The size and complex shape of the replacement teeth in the holotype of Bolosaurus grandis indicate that the replacement teeth can develop within the pulp cavity to an advanced stage while the previous generation remains functional for an extended time, reminiscent of the condition seen in other amniotes with occluding dentitions, including mammals.